tag:blogger.com,1999:blog-69262661861476557092024-02-07T16:58:30.900-08:00Basic Computersqnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.comBlogger15125tag:blogger.com,1999:blog-6926266186147655709.post-74515297899038372892008-10-14T18:45:00.000-07:002008-10-14T18:58:07.389-07:00<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgID2lGuFzSU0DrqCdsPYYteeRX3FTBDOCcx5b-OTq1m1RbiSblozbaUlEW3uCROfOM3wZ8H6t49OuRDWRGLkMBjME8l_S4vsPw5V2f63xcpdE_3yl-CxwtH2Opjg6bPuWCkJ4r6I57t5AX/s1600-h/hdd0.gif"><img style="margin: 0pt 10px 10px 0pt; float: left; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgID2lGuFzSU0DrqCdsPYYteeRX3FTBDOCcx5b-OTq1m1RbiSblozbaUlEW3uCROfOM3wZ8H6t49OuRDWRGLkMBjME8l_S4vsPw5V2f63xcpdE_3yl-CxwtH2Opjg6bPuWCkJ4r6I57t5AX/s320/hdd0.gif" alt="" id="BLOGGER_PHOTO_ID_5257191602607535138" border="0" /></a>Hard disk drive ABCs <p>The <a href="http://www.blogger.com/jargon/h/harddriv.htm">hard disk drive</a> is the primary storage location where data is permanently stored. Below is an illustration of what the inside of the hard disk drive may look like. The four main components of a hard disk drive are the <a href="http://www.blogger.com/jargon/p/platter.htm">platters</a>, <a href="http://www.blogger.com/jargon/a/aarm.htm">head arm</a>, <a href="http://www.blogger.com/jargon/c/chassis.htm">chassis</a>, and the <a href="http://www.blogger.com/jargon/a/actuator.htm">head actuator</a>.</p> <p align="center"><br /></p> <p>The majority of computer hard disk drives are permanently stored in an <a href="http://www.blogger.com/jargon/i/internal.htm">internal</a> <a href="http://www.blogger.com/jargon/d/drivebay.htm">drive bay</a> at the front of the computer and are connected with one <a href="http://www.blogger.com/jargon/a/ata.htm">ATA</a> / <a href="http://www.blogger.com/jargon/s/scsi.htm">SCSI</a> cable and power cable. Unlike other drives, the hard disk drive is the only drive that is not physically accessed by the user like the <a href="http://www.blogger.com/floppy.htm">floppy disk drive</a> or the <a href="http://www.blogger.com/cdrom.htm">CD-ROM drive</a>.</p><br /><p class="nb"><a name="02"></a>Size information</p> <p>The capacity of a computer hard disk drives and the files it contains can be confusing. Below is a listing of the standards in different size values. It is important to realize that not all manufacturers and developers use these values. For example, a manufacturer may consider a gigabyte as the value of a gibibyte.</p> <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tbody> <tr> <td><small><b><a href="http://www.blogger.com/jargon/b/bit.htm">Bit</a></b></small></td> <td><small> Value of 0 or 1</small></td></tr> <tr> <td><small><b><a href="http://www.blogger.com/jargon/n/nibble.htm">Nibble</a></b></small></td> <td><small> 4 Bits</small></td></tr> <tr> <td><small><b><a href="http://www.blogger.com/jargon/b/byte.htm">Byte</a></b></small></td> <td><small> 8 Bits</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/k/kilobit.htm"><b>Kilobit</b></a></small></td> <td><small>1,000 bits</small></td></tr> <tr> <td><small><b><a href="http://www.blogger.com/jargon/k/kilobyte.htm">Kilobyte</a></b></small></td> <td><small>1,000 bytes</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/k/kibibit.htm"><b>Kibibit</b> </a></small></td> <td><small>1,024 bits</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/k/kibibyte.htm"><b>Kibibyte</b> </a></small></td> <td><small>1,024 bytes</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/m/mebibit.htm"><b>Mebibit</b> </a></small></td> <td><small>1,048,576 bits</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/m/mebibyte.htm"><b>Mebibyte</b> </a></small></td> <td><small>1,048,576 bytes</small></td></tr> <tr> <td><small><b><a href="http://www.blogger.com/jargon/m/mb.htm">Megabit</a></b></small></td> <td><small>1,000,000 bits</small></td></tr> <tr> <td><small><b><a href="http://www.blogger.com/jargon/m/mb.htm">Megabyte</a></b></small></td> <td><small>1,000,000 bytes</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/g/gibibit.htm"><b>Gibibit</b></a></small></td> <td><small>1,073,741,824 bits</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/g/gibibyte.htm"><b>Gibibyte</b> </a></small></td> <td><small>1,073,741,824 bytes</small></td></tr> <tr> <td><small><b><a href="http://www.blogger.com/jargon/g/gb.htm">Gigabyte</a></b></small></td> <td><small>1,000,000,000 bytes</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/g/gigabit.htm"><b>Gigabit</b></a></small></td> <td><small>1,000,000,000 bits</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/t/tebibit.htm"><b>Tebibit</b></a></small></td> <td><small>1,099,511,627,776 bits</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/t/tebibyte.htm"><b>Tebibyte</b> </a></small></td> <td><small>1,099,511,627,776 bytes</small></td></tr> <tr> <td><small><b><a href="http://www.blogger.com/jargon/t/tb.htm">Terabyte</a></b></small></td> <td><small>1,000,000,000,000 bytes </small></td></tr> <tr> <td><small><b><a href="http://www.blogger.com/jargon/t/terabit.htm">Terabit</a></b></small></td> <td><small>1,000,000,000,000 bits </small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/p/pebibit.htm"><b>Pebibit</b></a></small></td> <td><small>1,125,899,906,842,624 bits</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/p/pebibyte.htm"><b>Pebibyte</b> </a></small></td> <td><small>1,125,899,906,842,624 bytes</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/p/petabit.htm"><b>Petabit</b> </a></small></td> <td><small>1,000,000,000,000,000 bits</small></td></tr> <tr> <td><small><b><a href="http://www.blogger.com/jargon/p/petabyte.htm">Petabyte</a></b></small></td> <td><small>1,000,000,000,000,000 bytes</small></td></tr> <tr> <td><small><b><a href="http://www.blogger.com/jargon/e/eb.htm">Exabyte</a></b></small></td> <td><small>10<sup>18</sup> bytes</small></td></tr> <tr> <td><small><b><a href="http://www.blogger.com/jargon/e/exabit.htm">Exabit</a></b></small></td> <td><small>10<sup>18</sup> bits</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/e/exbibit.htm"><b>Exbibit</b></a></small></td> <td><small>2<sup>60</sup> bits</small></td></tr> <tr> <td><small><a href="http://www.blogger.com/jargon/e/exbibyte.htm"><b>Exbibyte</b> </a></small></td> <td><small>2<sup>60</sup> bytes</small></td></tr> <tr> <td><small><b><a href="http://www.blogger.com/jargon/z/zettabyt.htm">Zettabyte</a></b></small></td> <td><small>10<sup>21 </sup>bytes</small></td></tr> <tr> <td><small><b><a href="http://www.blogger.com/jargon/y/yottabyt.htm">Yottabyte</a></b></small></td> <td><small>10<sup>24 </sup>bytes</small></td></tr></tbody></table><p><br /></p>qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0tag:blogger.com,1999:blog-6926266186147655709.post-45315735654172318822008-07-02T03:21:00.000-07:002008-07-02T04:22:23.029-07:00<div style="text-align: center;"><span style="font-size:130%;"><span style="color: rgb(0, 102, 0);">An </span></span><span style="color: rgb(0, 102, 0);font-family:trebuchet ms;font-size:130%;" >Illustrated History of Computers </span> <span style="color: rgb(0, 102, 0); font-weight: bold;">Part 4</span></div><div style="text-align: center;"><span style=";font-family:trebuchet ms;font-size:130%;" > </span></div><div style="text-align: center; color: rgb(0, 102, 0);"><span style="font-size:130%;"> </span></div><div style="font-family: trebuchet ms; text-align: center;">
<br /></div><div style="text-align: center;"><span style="font-family:trebuchet ms;">___________________________________ </span> </div><div style="text-align: justify;font-family:trebuchet ms;">
<br /><span style="font-size:130%;"><span style="color: rgb(0, 102, 0);">T</span></span>he title of forefather of today's all-electronic digital computers is usually awarded to ENIAC, which stood for Electronic Numerical Integrator and Calculator. ENIAC was built at the University of Pennsylvania between 1943 and 1945 by two professors, John Mauchly and the 24 year old J. Presper Eckert, who got funding from the war department after promising they could build a machine that would replace all the "computers", meaning the women who were employed calculating the firing tables for the army's artillery guns. The day that Mauchly and Eckert saw the first small piece of ENIAC work, the persons they ran to bring to their lab to show off their progress were some of these female computers (one of whom remarked, "I was astounded that it took all this equipment to multiply 5 by 1000").
<br />
<br />ENIAC filled a 20 by 40 foot room, weighed 30 tons, and used more than 18,000 vacuum tubes. Like the Mark I, ENIAC employed paper card readers obtained from IBM (these were a regular product for IBM, as they were a long established part of business accounting machines, IBM's forte). When operating, the ENIAC was silent but you knew it was on as the 18,000 vacuum tubes each generated waste heat like a light bulb and all this heat (174,000 watts of heat) meant that the computer could only be operated in a specially designed room with its own heavy duty air conditioning system. Only the left half of ENIAC is visible in the first picture, the right half was basically a mirror image of what's visible.
<br />
<br /><div style="text-align: center;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3EsinR1jxJ3Sz43GWHltmb83mt-cKK4aK6l3TnbbcNJnVaSj5yno4tODcLdPtMm0sd3Ml2am8bpBdDolRwqsfOgUOe4zpKOWaRtbjisiypyc1oQAcv25RoXel7Nyrw2aH6oJtAVA6tamu/s1600-h/eniac1.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3EsinR1jxJ3Sz43GWHltmb83mt-cKK4aK6l3TnbbcNJnVaSj5yno4tODcLdPtMm0sd3Ml2am8bpBdDolRwqsfOgUOe4zpKOWaRtbjisiypyc1oQAcv25RoXel7Nyrw2aH6oJtAVA6tamu/s320/eniac1.jpeg" alt="" id="BLOGGER_PHOTO_ID_5218361174729618850" border="0" /></a><span style="font-size:85%;"><span style="font-weight: bold; color: rgb(0, 102, 0);">Two views of ENIAC: the "Electronic Numerical Integrator and Calculator" (note that it wasn't even given the name of computer since "computers" were people) [U.S. Army photo]</span></span>
<br /></div><div style="text-align: center;">
<br /></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhI4zmbKFZnUwP6DSM-oas9Z7TrzCoK2O2l-XNvyA9qYM11qSPXdYAbytkwXwTDApYvZhzBMqVNrQsL33oL3X0quGW-7cfdgcZbx-LEb8k1ONhuE03jicSDgvaxBs5B_FzKVRfiloDeTWct/s1600-h/ENIAC02.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhI4zmbKFZnUwP6DSM-oas9Z7TrzCoK2O2l-XNvyA9qYM11qSPXdYAbytkwXwTDApYvZhzBMqVNrQsL33oL3X0quGW-7cfdgcZbx-LEb8k1ONhuE03jicSDgvaxBs5B_FzKVRfiloDeTWct/s320/ENIAC02.jpeg" alt="" id="BLOGGER_PHOTO_ID_5218361251334480706" border="0" /></a>
<br />
<br />To reprogram the ENIAC you had to rearrange the patch cords that you can observe on the left in the prior photo, and the settings of 3000 switches that you can observe on the right. To program a modern computer, you type out a program with statements like:
<br />
<br />
<br />Circumference = 3.14 * diameter
<br />
<br />
<br />To perform this computation on ENIAC you had to rearrange a large number of patch cords and then locate three particular knobs on that vast wall of knobs and set them to 3, 1, and 4.
<br />
<br /><div style="text-align: center;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjjY-9IzePHBmpRKscLBckyZUhd2lvVvrNvGOCvi2WH2iuOviq436xtsJAQo2H47S-0A2oyO_h6X6vjG7RnNYFl12qDikifGXQjvugmdiuLMa-800od4xTX61QtO7Tx22Hk7-rjTqCS7Qcb/s1600-h/eniac4.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjjY-9IzePHBmpRKscLBckyZUhd2lvVvrNvGOCvi2WH2iuOviq436xtsJAQo2H47S-0A2oyO_h6X6vjG7RnNYFl12qDikifGXQjvugmdiuLMa-800od4xTX61QtO7Tx22Hk7-rjTqCS7Qcb/s320/eniac4.gif" alt="" id="BLOGGER_PHOTO_ID_5218361719972342898" border="0" /></a><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >Reprogramming ENIAC involved a hike [U.S. Army photo]</span>
<br /></div>
<br />
<br />Once the army agreed to fund ENIAC, Mauchly and Eckert worked around the clock, seven days a week, hoping to complete the machine in time to contribute to the war. Their war-time effort was so intense that most days they ate all 3 meals in the company of the army Captain who was their liaison with their military sponsors. They were allowed a small staff but soon observed that they could hire only the most junior members of the University of Pennsylvania staff because the more experienced faculty members knew that their proposed machine would never work.
<br />
<br />One of the most obvious problems was that the design would require 18,000 vacuum tubes to all work simultaneously. Vacuum tubes were so notoriously unreliable that even twenty years later many neighborhood drug stores provided a "tube tester" that allowed homeowners to bring in the vacuum tubes from their television sets and determine which one of the tubes was causing their TV to fail. And television sets only incorporated about 30 vacuum tubes. The device that used the largest number of vacuum tubes was an electronic organ: it incorporated 160 tubes. The idea that 18,000 tubes could function together was considered so unlikely that the dominant vacuum tube supplier of the day, RCA, refused to join the project (but did supply tubes in the interest of "wartime cooperation"). Eckert solved the tube reliability problem through extremely careful circuit design. He was so thorough that before he chose the type of wire cabling he would employ in ENIAC he first ran an experiment where he starved lab rats for a few days and then gave them samples of all the available types of cable to determine which they least liked to eat. Here's a look at a small number of the vacuum tubes in ENIAC:
<br />
<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEs6fWArUTso7UeFUpqvsM4VHcf8ELaSQfuQ9l2FnWUQwi3Jidz3IW9AhQf5eZwFa0hFUGErj-qhY690WztEw49VPqTZ7GFokz00k-hlBLezcXDmHsfGKP-0rD-fBsgxFe1rf4TAuH6Tmt/s1600-h/eniac3.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEs6fWArUTso7UeFUpqvsM4VHcf8ELaSQfuQ9l2FnWUQwi3Jidz3IW9AhQf5eZwFa0hFUGErj-qhY690WztEw49VPqTZ7GFokz00k-hlBLezcXDmHsfGKP-0rD-fBsgxFe1rf4TAuH6Tmt/s320/eniac3.gif" alt="" id="BLOGGER_PHOTO_ID_5218361344625120322" border="0" /></a>
<br />
<br />Even with 18,000 vacuum tubes, ENIAC could only hold 20 numbers at a time. However, thanks to the elimination of moving parts it ran much faster than the Mark I: a multiplication that required 6 seconds on the Mark I could be performed on ENIAC in 2.8 thousandths of a second. ENIAC's basic clock speed was 100,000 cycles per second. Today's home computers employ clock speeds of 1,000,000,000 cycles per second. Built with $500,000 from the U.S. Army, ENIAC's first task was to compute whether or not it was possible to build a hydrogen bomb (the atomic bomb was completed during the war and hence is older than ENIAC). The very first problem run on ENIAC required only 20 seconds and was checked against an answer obtained after forty hours of work with a mechanical calculator. After chewing on half a million punch cards for six weeks, ENIAC did humanity no favor when it declared the hydrogen bomb feasible. This first ENIAC program remains classified even today.
<br />
<br />Once ENIAC was finished and proved worthy of the cost of its development, its designers set about to eliminate the obnoxious fact that reprogramming the computer required a physical modification of all the patch cords and switches. It took days to change ENIAC's program. Eckert and Mauchly's next teamed up with the mathematician John von Neumann to design EDVAC, which pioneered the stored program. Because he was the first to publish a description of this new computer, von Neumann is often wrongly credited with the realization that the program (that is, the sequence of computation steps) could be represented electronically just as the data was. But this major breakthrough can be found in Eckert's notes long before he ever started working with von Neumann. Eckert was no slouch: while in high school Eckert had scored the second highest math SAT score in the entire country.
<br />
<br />After ENIAC and EDVAC came other computers with humorous names such as ILLIAC, JOHNNIAC, and, of course, MANIAC. ILLIAC was built at the University of Illinois at Champaign-Urbana, which is probably why the science fiction author Arthur C. Clarke chose to have the HAL computer of his famous book "2001: A Space Odyssey" born at Champaign-Urbana. Have you ever noticed that you can shift each of the letters of IBM backward by one alphabet position and get HAL?
<br />
<br />
<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDvdW4LLhI6kU9C54m7webBYjKSLzj7AbX-BhcJwZmnNYWW94Cclo8o7BtwVUz9vziqoupVrlWSW_ZDQPVtD-qSuVluyd8YgtJZyFpbjZb8nWDOql5c0K2iNi6hrlnzomt-DGNJjo8e6qZ/s1600-h/ILLIAC2.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDvdW4LLhI6kU9C54m7webBYjKSLzj7AbX-BhcJwZmnNYWW94Cclo8o7BtwVUz9vziqoupVrlWSW_ZDQPVtD-qSuVluyd8YgtJZyFpbjZb8nWDOql5c0K2iNi6hrlnzomt-DGNJjo8e6qZ/s320/ILLIAC2.jpeg" alt="" id="BLOGGER_PHOTO_ID_5218362166892496498" border="0" /></a><span style="color: rgb(0, 102, 0);font-size:85%;" >
<br /></span><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >ILLIAC II built at the University of Illinois (it is a good thing computers were one-of-a-kind creations in these days, can you imagine being asked to duplicate this?)</span>
<br /></div>
<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5rInHigTWDVwHBdInT41sP20WKc6EWUjEP8wKLwfijzjJMZRgZcyPWb7ujzhLHJdYAZSY2R2-3cT_2hM7v1r10zAeYbgR_GOvj7dHlqCJdVzIT1Tkao3ia4a1bJU27ZaIK7MudwozoApA/s1600-h/HAL.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5rInHigTWDVwHBdInT41sP20WKc6EWUjEP8wKLwfijzjJMZRgZcyPWb7ujzhLHJdYAZSY2R2-3cT_2hM7v1r10zAeYbgR_GOvj7dHlqCJdVzIT1Tkao3ia4a1bJU27ZaIK7MudwozoApA/s320/HAL.gif" alt="" id="BLOGGER_PHOTO_ID_5218368010107161698" border="0" /></a><span style="font-weight: bold;font-size:85%;" >
<br /></span><div style="text-align: center;"><span style="font-weight: bold;font-size:85%;" ><span style="color: rgb(0, 102, 0);">HAL from the movie "2001: A Space Odyssey". Look at the previous picture to understand why the movie makers in 1968 assumed computers of the future would be things you walk into.</span></span>
<br /></div>
<br />
<br />JOHNNIAC was a reference to John von Neumann, who was unquestionably a genius. At age 6 he could tell jokes in classical Greek. By 8 he was doing calculus. He could recite books he had read years earlier word for word. He could read a page of the phone directory and then recite it backwards. On one occasion it took von Neumann only 6 minutes to solve a problem in his head that another professor had spent hours on using a mechanical calculator. Von Neumann is perhaps most famous (infamous?) as the man who worked out the complicated method needed to detonate an atomic bomb.
<br />
<br />Once the computer's program was represented electronically, modifications to that program could happen as fast as the computer could compute. In fact, computer programs could now modify themselves while they ran (such programs are called self-modifying programs). This introduced a new way for a program to fail: faulty logic in the program could cause it to damage itself. This is one source of the general protection fault famous in MS-DOS and the blue screen of death famous in Windows.
<br />
<br />Today, one of the most notable characteristics of a computer is the fact that its ability to be reprogrammed allows it to contribute to a wide variety of endeavors, such as the following completely unrelated fields:
<br />
<br />the creation of special effects for movies,
<br />the compression of music to allow more minutes of music to fit within the limited memory of an MP3 player,
<br />the observation of car tire rotation to detect and prevent skids in an anti-lock braking system (ABS),
<br />the analysis of the writing style in Shakespeare's work with the goal of proving whether a single individual really was responsible for all these pieces.
<br />By the end of the 1950's computers were no longer one-of-a-kind hand built devices owned only by universities and government research labs. Eckert and Mauchly left the University of Pennsylvania over a dispute about who owned the patents for their invention. They decided to set up their own company. Their first product was the famous UNIVAC computer, the first commercial (that is, mass produced) computer. In the 50's, UNIVAC (a contraction of "Universal Automatic Computer") was the household word for "computer" just as "Kleenex" is for "tissue". The first UNIVAC was sold, appropriately enough, to the Census bureau. UNIVAC was also the first computer to employ magnetic tape. Many people still confuse a picture of a reel-to-reel tape recorder with a picture of a mainframe computer.
<br />
<br />
<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgArhnMfAhyphenhyphenEa-mDGWRSZjOEp00scGErgUVlCckaoGOAvvgYHcnaSVcJHPPcrxsvZt3cWaa7gbfLK26Wt1Pms4FconTqjgrEKrgmbBohpB1bdYZKEXZ0dPKriJVHbfkFYmGn6uCICwAl9Ht/s1600-h/TapeDrive.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgArhnMfAhyphenhyphenEa-mDGWRSZjOEp00scGErgUVlCckaoGOAvvgYHcnaSVcJHPPcrxsvZt3cWaa7gbfLK26Wt1Pms4FconTqjgrEKrgmbBohpB1bdYZKEXZ0dPKriJVHbfkFYmGn6uCICwAl9Ht/s320/TapeDrive.jpeg" alt="" id="BLOGGER_PHOTO_ID_5218363482303880306" border="0" /></a> <div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >A reel-to-reel tape drive [photo courtesy of The Computer Museum]</span>
<br /></div>
<br />ENIAC was unquestionably the origin of the U.S. commercial computer industry, but its inventors, Mauchly and Eckert, never achieved fortune from their work and their company fell into financial problems and was sold at a loss. By 1955 IBM was selling more computers than UNIVAC and by the 1960's the group of eight companies selling computers was known as "IBM and the seven dwarfs". IBM grew so dominant that the federal government pursued anti-trust proceedings against them from 1969 to 1982 (notice the pace of our country's legal system). You might wonder what type of event is required to dislodge an industry heavyweight. In IBM's case it was their own decision to hire an unknown but aggressive firm called Microsoft to provide the software for their personal computer (PC). This lucrative contract allowed Microsoft to grow so dominant that by the year 2000 their market capitalization (the total value of their stock) was twice that of IBM and they were convicted in Federal Court of running an illegal monopoly.
<br />
<br />If you learned computer programming in the 1970's, you dealt with what today are called mainframe computers, such as the IBM 7090 (shown below), IBM 360, or IBM 370.
<br />
<br />
<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxQp619WPv6C6EaEeBF8f7Nbv4Iwgimt4baE40sInQrtNLM1ePXICXTs6_MZCRjYcMRsSp0GCGMmupS_7uCV4oJuhUe7d6MGxBTRP8ZrO1UpS5VsdGT7p_PVfa_3d3u-MlU7S73k-MtH_E/s1600-h/IBM7094.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxQp619WPv6C6EaEeBF8f7Nbv4Iwgimt4baE40sInQrtNLM1ePXICXTs6_MZCRjYcMRsSp0GCGMmupS_7uCV4oJuhUe7d6MGxBTRP8ZrO1UpS5VsdGT7p_PVfa_3d3u-MlU7S73k-MtH_E/s320/IBM7094.jpeg" alt="" id="BLOGGER_PHOTO_ID_5218362007345642914" border="0" /></a>
<br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >The IBM 7094, a typical mainframe computer [photo courtesy of IBM]</span>
<br /></div>
<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_KjyRAr8bF3Nti_FTyqclYpovAXFfPRgVl_2_0cLUc1nL_1AqZWMfoGccBBZco7lku2H7hyphenhyphen2RAeEctBAfPM7ydd5I6wgjIQ0UbxDRZPClguWfhJakXPF3ifddDIwg_3_ONOVOHMgI62xy/s1600-h/Mainframe.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_KjyRAr8bF3Nti_FTyqclYpovAXFfPRgVl_2_0cLUc1nL_1AqZWMfoGccBBZco7lku2H7hyphenhyphen2RAeEctBAfPM7ydd5I6wgjIQ0UbxDRZPClguWfhJakXPF3ifddDIwg_3_ONOVOHMgI62xy/s320/Mainframe.gif" alt="" id="BLOGGER_PHOTO_ID_5218362337569014050" border="0" /></a>
<br />There were 2 ways to interact with a mainframe. The first was called time sharing because the computer gave each user a tiny sliver of time in a round-robin fashion. Perhaps 100 users would be simultaneously logged on, each typing on a teletype such as the following:
<br />
<br />
<br /><div style="text-align: center;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOoYM9KU1jqoMKd9nJt6GFtJbkU_QZFVFO-D1_ADciKHNjMRwXpWRrnw_Dpfg76It4UOCpBsr9UUfpERJNF6glGfIDOc_WMV5ARMCgl2x0DlPM2ICHddYBpNI2jNmjZLQMppxg57AQf-4j/s1600-h/TeletypeASR33.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOoYM9KU1jqoMKd9nJt6GFtJbkU_QZFVFO-D1_ADciKHNjMRwXpWRrnw_Dpfg76It4UOCpBsr9UUfpERJNF6glGfIDOc_WMV5ARMCgl2x0DlPM2ICHddYBpNI2jNmjZLQMppxg57AQf-4j/s320/TeletypeASR33.jpeg" alt="" id="BLOGGER_PHOTO_ID_5218363560644733842" border="0" /></a><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >The Teletype was the standard mechanism used to interact with a time-sharing computer</span>
<br /></div>
<br />A teletype was a motorized typewriter that could transmit your keystrokes to the mainframe and then print the computer's response on its roll of paper. You typed a single line of text, hit the carriage return button, and waited for the teletype to begin noisily printing the computer's response (at a whopping 10 characters per second). On the left-hand side of the teletype in the prior picture you can observe a paper tape reader and writer (i.e., puncher). Here's a close-up of paper tape:
<br />
<br />
<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_RUrgAFFIy66QwluZqNBzCyrziBNysUDSmU7quMVmIW-Ti2WMq6F3hmCcApgtReSXrJw5Jwf5Urp9EsrTq3_aLIZyFBPJ5NKIsPPBFFnEpZET_nQ1qIn8vCpPOjwhsSG42_9K4cH80WE8/s1600-h/PaperTape.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_RUrgAFFIy66QwluZqNBzCyrziBNysUDSmU7quMVmIW-Ti2WMq6F3hmCcApgtReSXrJw5Jwf5Urp9EsrTq3_aLIZyFBPJ5NKIsPPBFFnEpZET_nQ1qIn8vCpPOjwhsSG42_9K4cH80WE8/s320/PaperTape.gif" alt="" id="BLOGGER_PHOTO_ID_5218363383166005634" border="0" /></a>
<br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >Three views of paper tape</span>
<br /></div>
<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEia5VzMVTDyHU2atuD4gwudqqzcCj7icuDGCQw2lOQR4iCQ2FP9g8Vk_7rYtFqVYlnUSEu5fMLkKx4lpWAX1IfI-EjKyOK_nxk0aCOMjUI9KlqV6nyvGrsuqslRzSTksRaAHQZMrgTkFqzQ/s1600-h/PaperTape2.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEia5VzMVTDyHU2atuD4gwudqqzcCj7icuDGCQw2lOQR4iCQ2FP9g8Vk_7rYtFqVYlnUSEu5fMLkKx4lpWAX1IfI-EjKyOK_nxk0aCOMjUI9KlqV6nyvGrsuqslRzSTksRaAHQZMrgTkFqzQ/s320/PaperTape2.jpeg" alt="" id="BLOGGER_PHOTO_ID_5218363140632339938" border="0" /></a>
<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGTyZyV-sfzpEESnXukjJk_aplfwQK8VjC3SlCd7tTHPCDng3t8FMJL60BUEzLbMoUb5Yt-EyWal0eDfkAGC8uqxsPhXNyGMrfedngKTaAo8AIghfjSJVJnaspqFSg7L-ZGlIacw-iT4tl/s1600-h/PaperTape3.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGTyZyV-sfzpEESnXukjJk_aplfwQK8VjC3SlCd7tTHPCDng3t8FMJL60BUEzLbMoUb5Yt-EyWal0eDfkAGC8uqxsPhXNyGMrfedngKTaAo8AIghfjSJVJnaspqFSg7L-ZGlIacw-iT4tl/s320/PaperTape3.gif" alt="" id="BLOGGER_PHOTO_ID_5218363226342169010" border="0" /></a>
<br />
<br />After observing the holes in paper tape it is perhaps obvious why all computers use binary numbers to represent data: a binary bit (that is, one digit of a binary number) can only have the value of 0 or 1 (just as a decimal digit can only have the value of 0 thru 9). Something which can only take two states is very easy to manufacture, control, and sense. In the case of paper tape, the hole has either been punched or it has not. Electro-mechanical computers such as the Mark I used relays to represent data because a relay (which is just a motor driven switch) can only be open or closed. The earliest all-electronic computers used vacuum tubes as switches: they too were either open or closed. Transistors replaced vacuum tubes because they too could act as switches but were smaller, cheaper, and consumed less power.
<br />
<br />Paper tape has a long history as well. It was first used as an information storage medium by Sir Charles Wheatstone, who used it to store Morse code that was arriving via the newly invented telegraph (incidentally, Wheatstone was also the inventor of the accordion).
<br />
<br />The alternative to time sharing was batch mode processing, where the computer gives its full attention to your program. In exchange for getting the computer's full attention at run-time, you had to agree to prepare your program off-line on a key punch machine which generated punch cards.
<br />
<br /><div style="text-align: center;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7dNl29dDbtRLaNCKZsGRFUj5emEvvsTpDxmA9Fvp5yCleb32FNCFcGGMNXK1BLDfxEr8tfE-NM2Wr-7YzTGp810lgQCra-6S5vkEADz4IfsiHV9RWvTbcQpOLDIFrG-BH-HlGQ3Kvi39L/s1600-h/Keypunch.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7dNl29dDbtRLaNCKZsGRFUj5emEvvsTpDxmA9Fvp5yCleb32FNCFcGGMNXK1BLDfxEr8tfE-NM2Wr-7YzTGp810lgQCra-6S5vkEADz4IfsiHV9RWvTbcQpOLDIFrG-BH-HlGQ3Kvi39L/s320/Keypunch.jpeg" alt="" id="BLOGGER_PHOTO_ID_5218362263585319058" border="0" /></a><span style="font-weight: bold; color: rgb(0, 102, 0);font-size:85%;" >An IBM Key Punch machine which operates like a typewriter except it produces punched cards rather than a printed sheet of paper</span><span style="font-size:85%;">
<br /></span></div>
<br />
<br />University students in the 1970's bought blank cards a linear foot at a time from the university bookstore. Each card could hold only 1 program statement. To submit your program to the mainframe, you placed your stack of cards in the hopper of a card reader. Your program would be run whenever the computer made it that far. You often submitted your deck and then went to dinner or to bed and came back later hoping to see a successful printout showing your results. Obviously, a program run in batch mode could not be interactive.
<br />
<br />But things changed fast. By the 1990's a university student would typically own his own computer and have exclusive use of it in his dorm room.
<br />
<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEihjSSKTixlFdyqTidsstgmcuh4iobx5Q8tEI2a22sCZZ5lNGljnwp3H2EoNlfjlqknzwBbb6JOe-tZf_krRMBKz6CuolPlTuFwfWYcW5JZVLKMa0d768Vz4b40wJNgq5mXsOXKHFyGsYmk/s1600-h/IBM_PC.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEihjSSKTixlFdyqTidsstgmcuh4iobx5Q8tEI2a22sCZZ5lNGljnwp3H2EoNlfjlqknzwBbb6JOe-tZf_krRMBKz6CuolPlTuFwfWYcW5JZVLKMa0d768Vz4b40wJNgq5mXsOXKHFyGsYmk/s320/IBM_PC.jpeg" alt="" id="BLOGGER_PHOTO_ID_5218368967909751714" border="0" /></a>
<br /><div style="text-align: center;"><span style="font-size:85%;"><span style="font-weight: bold; color: rgb(0, 102, 0);">The original IBM Personal Computer (PC)</span></span>
<br /></div>
<br />This transformation was a result of the invention of the microprocessor. A microprocessor (uP) is a computer that is fabricated on an integrated circuit (IC). Computers had been around for 20 years before the first microprocessor was developed at Intel in 1971. The micro in the name microprocessor refers to the physical size. Intel didn't invent the electronic computer. But they were the first to succeed in cramming an entire computer on a single chip (IC). Intel was started in 1968 and initially produced only semiconductor memory (Intel invented both the DRAM and the EPROM, two memory technologies that are still going strong today). In 1969 they were approached by Busicom, a Japanese manufacturer of high performance calculators (these were typewriter sized units, the first shirt-pocket sized scientific calculator was the Hewlett-Packard HP35 introduced in 1972). Busicom wanted Intel to produce 12 custom calculator chips: one chip dedicated to the keyboard, another chip dedicated to the display, another for the printer, etc. But integrated circuits were (and are) expensive to design and this approach would have required Busicom to bear the full expense of developing 12 new chips since these 12 chips would only be of use to them.
<br />
<br />
<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghyAGpEs1ByOQEXfiGe9v1DZH_k8_z2zPnI22n0q_wVa28lUEifgGCJVCplXiRKmkHAULdvrQKA2U9KWq_BISoOG-qjLe7ehfQYgXROr49_hXbp-HMBzHEtHmiltwMtj3MFn88XZejjEvf/s1600-h/busicom.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghyAGpEs1ByOQEXfiGe9v1DZH_k8_z2zPnI22n0q_wVa28lUEifgGCJVCplXiRKmkHAULdvrQKA2U9KWq_BISoOG-qjLe7ehfQYgXROr49_hXbp-HMBzHEtHmiltwMtj3MFn88XZejjEvf/s320/busicom.jpeg" alt="" id="BLOGGER_PHOTO_ID_5218361112387426722" border="0" /></a>
<br /><div style="text-align: center;"><span style="font-size:85%;"><span style="font-weight: bold; color: rgb(0, 102, 0);">A typical Busicom desk calculator</span></span>
<br /></div>
<br />But a new Intel employee (Ted Hoff) convinced Busicom to instead accept a general purpose computer chip which, like all computers, could be reprogrammed for many different tasks (like controlling a keyboard, a display, a printer, etc.). Intel argued that since the chip could be reprogrammed for alternative purposes, the cost of developing it could be spread out over more users and hence would be less expensive to each user. The general purpose computer is adapted to each new purpose by writing a program which is a sequence of instructions stored in memory (which happened to be Intel's forte). Busicom agreed to pay Intel to design a general purpose chip and to get a price break since it would allow Intel to sell the resulting chip to others. But development of the chip took longer than expected and Busicom pulled out of the project. Intel knew it had a winner by that point and gladly refunded all of Busicom's investment just to gain sole rights to the device which they finished on their own.
<br />
<br />Thus became the Intel 4004, the first microprocessor (uP). The 4004 consisted of 2300 transistors and was clocked at 108 kHz (i.e., 108,000 times per second). Compare this to the 42 million transistors and the 2 GHz clock rate (i.e., 2,000,000,000 times per second) used in a Pentium 4. One of Intel's 4004 chips still functions aboard the Pioneer 10 spacecraft, which is now the man-made object farthest from the earth. Curiously, Busicom went bankrupt and never ended up using the ground-breaking microprocessor.
<br />
<br />Intel followed the 4004 with the 8008 and 8080. Intel priced the 8080 microprocessor at $360 dollars as an insult to IBM's famous 360 mainframe which cost millions of dollars. The 8080 was employed in the MITS Altair computer, which was the world's first personal computer (PC). It was personal all right: you had to build it yourself from a kit of parts that arrived in the mail. This kit didn't even include an enclosure and that is the reason the unit shown below doesn't match the picture on the magazine cover.
<br />
<br />
<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgr_KYtahoC1VSfmQ6csbCk0lAg1TWffTe9rrySiS8d5RPoPZSXTCyef_Ueozot8HYp1dU1bKwn35GKk2FW-VF6yeGncbxlsmE-gADIPmg1gUNXyU1yT1ljYLUGFYapqo9ptQUiX9eRUsTb/s1600-h/Altair.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgr_KYtahoC1VSfmQ6csbCk0lAg1TWffTe9rrySiS8d5RPoPZSXTCyef_Ueozot8HYp1dU1bKwn35GKk2FW-VF6yeGncbxlsmE-gADIPmg1gUNXyU1yT1ljYLUGFYapqo9ptQUiX9eRUsTb/s320/Altair.jpeg" alt="" id="BLOGGER_PHOTO_ID_5218361041078724706" border="0" /></a>
<br /><div style="text-align: center;"><span style="font-size:85%;"><span style="color: rgb(0, 102, 0); font-weight: bold;">The Altair 8800, the first PC</span></span>
<br /></div>
<br />A Harvard freshman by the name of Bill Gates decided to drop out of college so he could concentrate all his time writing programs for this computer. This early experienced put Bill Gates in the right place at the right time once IBM decided to standardize on the Intel microprocessors for their line of PCs in 1981. The Intel Pentium 4 used in today's PCs is still compatible with the Intel 8088 used in IBM's first PC.
<br /><basefont></div><p style="text-align: justify;font-family:trebuchet ms;">If you've enjoyed this history of computers, I encourage you to try your own hand at programming a computer. That is the only way you will really come to understand the concepts of looping, subroutines, high and low-level languages, bits and bytes, etc. I have written a number of Windows programs which teach computer programming in a fun, visually-engaging setting. I start my students on a programmable RPN calculator where we learn about programs, statements, program and data memory, subroutines, logic and syntax errors, stacks, etc. Then we move on to an 8051 microprocessor (which happens to be the most widespread microprocessor on earth) where we learn about microprocessors, bits and bytes, assembly language, addressing modes, etc. Finally, we graduate to the most powerful language in use today: C++ (pronounced "C plus plus"). These Windows programs are accompanied by a book's worth of on-line documentation which serves as a self-study guide, allowing you to teach yourself computer programming! The home page (URL) for this collection of software is <span style="font-size:85%;"><a href="http://www.computersciencelab.com/">www.computersciencelab.com</a></span>. </p><p style="text-align: justify;font-family:trebuchet ms;">
<br /><span style="font-style: italic;">Bibliography:</span> </p><p style="text-align: justify;font-family:trebuchet ms;"><span style="font-size:85%;">"ENIAC: The Triumphs and Tragedies of the World's First Computer" by Scott McCartney.</span></p><p style="text-align: justify;font-family:trebuchet ms;"><span style="font-style: italic;">
<br /></span></p><p style="text-align: justify;font-family:trebuchet ms;"><span style="font-style: italic;"></span><span style="font-size:85%;">by: http://www.computersciencelab.com/</span></p><span style="font-style: italic;font-size:85%;" ></span><p style="text-align: justify;">
<br /></p><div style="text-align: justify;">
<br /></div>
<br />qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0tag:blogger.com,1999:blog-6926266186147655709.post-39890423099527594332008-07-01T05:25:00.000-07:002008-07-02T04:21:28.055-07:00<div style="text-align: justify;"><div style="text-align: center;"><span style="font-size:130%;"><span style="color: rgb(0, 102, 0);">An Illustrated History of Computers</span> <span style="color: rgb(0, 102, 0);">Part 3</span><br /></span></div><br /><div style="text-align: center;">___________________________________<br /></div><br /><br /><span style="font-weight: bold;font-size:130%;" >I</span>BM continued to develop mechanical calculators for sale to businesses to help with financial accounting and inventory accounting. One characteristic of both financial accounting and inventory accounting is that although you need to subtract, you don't need negative numbers and you really don't have to multiply since multiplication can be accomplished via repeated addition.<br /><br />But the U.S. military desired a mechanical calculator more optimized for scientific computation. By World War II the U.S. had battleships that could lob shells weighing as much as a small car over distances up to 25 miles. Physicists could write the equations that described how atmospheric drag, wind, gravity, muzzle velocity, etc. would determine the trajectory of the shell. But solving such equations was extremely laborious. This was the work performed by the human computers. Their results would be published in ballistic "firing tables" published in gunnery manuals. During World War II the U.S. military scoured the country looking for (generally female) math majors to hire for the job of computing these tables. But not enough humans could be found to keep up with the need for new tables. Sometimes artillery pieces had to be delivered to the battlefield without the necessary firing tables and this meant they were close to useless because they couldn't be aimed properly. Faced with this situation, the U.S. military was willing to invest in even hair-brained schemes to automate this type of computation.<br /><br />One early success was the Harvard Mark I computer which was built as a partnership between Harvard and IBM in 1944. This was the first programmable digital computer made in the U.S. But it was not a purely electronic computer. Instead the Mark I was constructed out of switches, relays, rotating shafts, and clutches. The machine weighed 5 tons, incorporated 500 miles of wire, was 8 feet tall and 51 feet long, and had a 50 ft rotating shaft running its length, turned by a 5 horsepower electric motor. The Mark I ran non-stop for 15 years, sounding like a roomful of ladies knitting. To appreciate the scale of this machine note the four typewriters in the foreground of the following photo.<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTxTHSwZFZOBbfbJdI0pGJtLZj2xa0z5Ie2JGVdFvxr2ULUjosQbex_vutYcrQFDrRePf-eA4qjRlyyq2cy_hgthpfQqNETCzuF05CzHZFAFGfMyMt0Ne8nW4Ku-SrNigxcS0fqVHqQA-3/s1600-h/mark1.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTxTHSwZFZOBbfbJdI0pGJtLZj2xa0z5Ie2JGVdFvxr2ULUjosQbex_vutYcrQFDrRePf-eA4qjRlyyq2cy_hgthpfQqNETCzuF05CzHZFAFGfMyMt0Ne8nW4Ku-SrNigxcS0fqVHqQA-3/s320/mark1.jpg" alt="" id="BLOGGER_PHOTO_ID_5218022400276179442" border="0" /></a><br /></div><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >The Harvard Mark I: an electro-mechanical computer</span><br /></div><br /><div style="text-align: justify;"><br />You can see the 50 ft rotating shaft in the bottom of the prior photo. This shaft was a central power source for the entire machine. This design feature was reminiscent of the days when waterpower was used to run a machine shop and each lathe or other tool was driven by a belt connected to a single overhead shaft which was turned by an outside waterwheel.<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigHrhDebKP6xISYMIdrXuqVHhA7KiEGcWpfYYGgSb3wXp5HiLQWE0CJmT_yjtVWSLaOkNlc28H2XEucLGkQVuIR_gNRHYkHMlt9-O8PJYhuVipFyM-DCRr2JpGFWDQp9LDAnr6FIqPDeDA/s1600-h/OverheadBelt.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigHrhDebKP6xISYMIdrXuqVHhA7KiEGcWpfYYGgSb3wXp5HiLQWE0CJmT_yjtVWSLaOkNlc28H2XEucLGkQVuIR_gNRHYkHMlt9-O8PJYhuVipFyM-DCRr2JpGFWDQp9LDAnr6FIqPDeDA/s320/OverheadBelt.gif" alt="" id="BLOGGER_PHOTO_ID_5218022226302135938" border="0" /></a><br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >A central shaft driven by an outside waterwheel and connected to each machine by overhead belts was the customary power source for all the machines in a factory</span><br /></div><br />Here's a close-up of one of the Mark I's four paper tape readers. A paper tape was an improvement over a box of punched cards as anyone who has ever dropped -- and thus shuffled -- his "stack" knows.<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjhwLEJOQ0Xs9-G2qxTMclUz2yNh_Ojge0zcMJxRqeJdwvNU_zuQRyFqRo1HTgIH0hZphHG5eCrBXB3ZqM8GJIrGgko4HWyNpLQXq1kEF8s-w9RUHERyn35TOSqlby3JCFB_uoYjjo2OraY/s1600-h/MarkITapeReader.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjhwLEJOQ0Xs9-G2qxTMclUz2yNh_Ojge0zcMJxRqeJdwvNU_zuQRyFqRo1HTgIH0hZphHG5eCrBXB3ZqM8GJIrGgko4HWyNpLQXq1kEF8s-w9RUHERyn35TOSqlby3JCFB_uoYjjo2OraY/s320/MarkITapeReader.jpg" alt="" id="BLOGGER_PHOTO_ID_5218022330687194066" border="0" /></a> <div style="text-align: center; font-weight: bold;"><span style="color: rgb(0, 102, 0);font-size:85%;" >One of the four paper tape readers on the Harvard Mark I (you can observe the punched paper</span><span style="color: rgb(0, 102, 0);"> roll emerging from the bottom)</span> </div><br />One of the primary programmers for the Mark I was a woman, Grace Hopper. Hopper found the first computer "bug": a dead moth that had gotten into the Mark I and whose wings were blocking the reading of the holes in the paper tape. The word "bug" had been used to describe a defect since at least 1889 but Hopper is credited with coining the word "debugging" to describe the work to eliminate program faults.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8HXuD72uTudqcDhCAwHOEgcEuTolEmp_-WxbewqPM8ueeZmZi7RyaUhT0q5Bc9ZvWcDN6LzzNHRmvIfcjVvzRNca9cK7CcLDVCOi5hresNQeH-8e3Fe4kDJsujbTEif7RgrxWduzwWTqK/s1600-h/FirstBug.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8HXuD72uTudqcDhCAwHOEgcEuTolEmp_-WxbewqPM8ueeZmZi7RyaUhT0q5Bc9ZvWcDN6LzzNHRmvIfcjVvzRNca9cK7CcLDVCOi5hresNQeH-8e3Fe4kDJsujbTEif7RgrxWduzwWTqK/s320/FirstBug.jpg" alt="" id="BLOGGER_PHOTO_ID_5218022706968318818" border="0" /></a><br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >The first computer bug [photo © 2002 IEEE]</span><br /></div><br />In 1953 Grace Hopper invented the first high-level language, "Flow-matic". This language eventually became COBOL which was the language most affected by the infamous Y2K problem. A high-level language is designed to be more understandable by humans than is the binary language understood by the computing machinery. A high-level language is worthless without a program -- known as a compiler -- to translate it into the binary language of the computer and hence Grace Hopper also constructed the world's first compiler. Grace remained active as a Rear Admiral in the Navy Reserves until she was 79 (another record).<br /><br />The Mark I operated on numbers that were 23 digits wide. It could add or subtract two of these numbers in three-tenths of a second, multiply them in four seconds, and divide them in ten seconds. Forty-five years later computers could perform an addition in a billionth of a second! Even though the Mark I had three quarters of a million components, it could only store 72 numbers! Today, home computers can store 30 million numbers in RAM and another 10 billion numbers on their hard disk. Today, a number can be pulled from RAM after a delay of only a few billionths of a second, and from a hard disk after a delay of only a few thousandths of a second. This kind of speed is obviously impossible for a machine which must move a rotating shaft and that is why electronic computers killed off their mechanical predecessors.<br /><br />On a humorous note, the principal designer of the Mark I, Howard Aiken of Harvard, estimated in 1947 that six electronic digital computers would be sufficient to satisfy the computing needs of the entire United States. IBM had commissioned this study to determine whether it should bother developing this new invention into one of its standard products (up until then computers were one-of-a-kind items built by special arrangement). Aiken's prediction wasn't actually so bad as there were very few institutions (principally, the government and military) that could afford the cost of what was called a computer in 1947. He just didn't foresee the micro-electronics revolution which would allow something like an IBM Stretch computer of 1959:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhzNFcK6bMHiFXeh-dSPGJVikC907MXqfWk_GdIgKndSErAcD_gt0vujypzpcPWQMYNzzOxZf_0eTxREN_tQdLLAZ7MfhHGW1PBoViLf4ZOcbXaokfwDEwNz9MmtWcLY52VXad-NJ1WkZTA/s1600-h/IBMStretch.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhzNFcK6bMHiFXeh-dSPGJVikC907MXqfWk_GdIgKndSErAcD_gt0vujypzpcPWQMYNzzOxZf_0eTxREN_tQdLLAZ7MfhHGW1PBoViLf4ZOcbXaokfwDEwNz9MmtWcLY52VXad-NJ1WkZTA/s320/IBMStretch.jpg" alt="" id="BLOGGER_PHOTO_ID_5218022554158529954" border="0" /></a><br /><span style="color: rgb(0, 102, 0);">(that's just the operator's console, here's the rest of its 33 foot length:)</span><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi49igL-qhi_0r4jVvIoMkfSNEgtm-ptlbTc5olVMxDt-neNVzKw-_EPM_fWS1ojvKbQhiaIPFSRTHmCvCYvKZlbvjxN70vS5EiNG2L6oFH3fL5G81UuFJZZ1j2hCNKRh8YB4ZJGCAxpN6W/s1600-h/IBMStretch2.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi49igL-qhi_0r4jVvIoMkfSNEgtm-ptlbTc5olVMxDt-neNVzKw-_EPM_fWS1ojvKbQhiaIPFSRTHmCvCYvKZlbvjxN70vS5EiNG2L6oFH3fL5G81UuFJZZ1j2hCNKRh8YB4ZJGCAxpN6W/s320/IBMStretch2.jpg" alt="" id="BLOGGER_PHOTO_ID_5218022619298803506" border="0" /></a><br /><span style="color: rgb(0, 102, 0);">to be bested by a home computer of 1976 such as this Apple I which sold for only $600:</span><br /><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilDCkwte7mTujz_eiZdhuyCROoepkSZXFF-zid2A3PM1rkMFP0IMlm1sEQmaKTJL6MkVdsnfCTiBY-nbHrL7sK4tFvk29IIkC9SoceJGWavYC7EexvnULrwa8-ADqxPj4-sKaHb_2epMnr/s1600-h/Apple1.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilDCkwte7mTujz_eiZdhuyCROoepkSZXFF-zid2A3PM1rkMFP0IMlm1sEQmaKTJL6MkVdsnfCTiBY-nbHrL7sK4tFvk29IIkC9SoceJGWavYC7EexvnULrwa8-ADqxPj4-sKaHb_2epMnr/s320/Apple1.jpg" alt="" id="BLOGGER_PHOTO_ID_5218023121923579746" border="0" /></a><br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >The Apple 1 which was sold as a do-it-yourself kit (without the lovely case seen here)</span><br /></div><br />Computers had been incredibly expensive because they required so much hand assembly, such as the wiring seen in this CDC 7600:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmBWjOBsVl_dEf7WHvm22XUlU83p8KrIjmzeuljrtp-iTqEXXKSJmBqyrGN-XOZ3jUxk3pzNMAymmHVMyaYKupILWYpVDyWVYXeppDCJ-3Ig1Oo_iB4tGabIOfMNuaL-t71HSZlF-WPTFC/s1600-h/CDC7600.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmBWjOBsVl_dEf7WHvm22XUlU83p8KrIjmzeuljrtp-iTqEXXKSJmBqyrGN-XOZ3jUxk3pzNMAymmHVMyaYKupILWYpVDyWVYXeppDCJ-3Ig1Oo_iB4tGabIOfMNuaL-t71HSZlF-WPTFC/s320/CDC7600.jpg" alt="" id="BLOGGER_PHOTO_ID_5218023045020614290" border="0" /></a><br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >Typical wiring in an early mainframe computer [photo courtesy The Computer Museum]</span><br /></div><br />The microelectronics revolution is what allowed the amount of hand-crafted wiring seen in the prior photo to be mass-produced as an integrated circuit which is a small sliver of silicon the size of your thumbnail .<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIXnpG4veFe1Gm7VSn_5CAUEonzrwQuvoW96SdQBgDEGOwrJjZf2wa2TGL8sfbjAcYFEpvnnEsFoE5xBcY8XSDewP6ggyNUmAlq8nNnsis_b5GgB7-Cse1k9oLUdhInL4CbfIwj9ez4593/s1600-h/IC.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIXnpG4veFe1Gm7VSn_5CAUEonzrwQuvoW96SdQBgDEGOwrJjZf2wa2TGL8sfbjAcYFEpvnnEsFoE5xBcY8XSDewP6ggyNUmAlq8nNnsis_b5GgB7-Cse1k9oLUdhInL4CbfIwj9ez4593/s320/IC.jpg" alt="" id="BLOGGER_PHOTO_ID_5218022471140894930" border="0" /></a><br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >An integrated circuit ("silicon chip") [photo courtesy of IBM]</span><br /></div><br />The primary advantage of an integrated circuit is not that the transistors (switches) are miniscule (that's the secondary advantage), but rather that millions of transistors can be created and interconnected in a mass-production process. All the elements on the integrated circuit are fabricated simultaneously via a small number (maybe 12) of optical masks that define the geometry of each layer. This speeds up the process of fabricating the computer -- and hence reduces its cost -- just as Gutenberg's printing press sped up the fabrication of books and thereby made them affordable to all.<br /><br />The IBM Stretch computer of 1959 needed its 33 foot length to hold the 150,000 transistors it contained. These transistors were tremendously smaller than the vacuum tubes they replaced, but they were still individual elements requiring individual assembly. By the early 1980s this many transistors could be simultaneously fabricated on an integrated circuit. Today's Pentium 4 microprocessor contains 42,000,000 transistors in this same thumbnail sized piece of silicon.<br /><br />It's humorous to remember that in between the Stretch machine (which would be called a mainframe today) and the Apple I (a desktop computer) there was an entire industry segment referred to as mini-computers such as the following PDP-12 computer of 1969:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuvaC3KESBs0Q6wF8CmEYlh0TKgOzyz0lVPqm5plmZv_0MlEFiS27ou8paV5kzBj3rBaldVCdvRNBjKTR8VzTPQkKe4SmsD7I4EmBpyR6ngtKPcEPkd4WRduOez3NzFUcRLSOJ9JxOm1JI/s1600-h/decpdp12.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuvaC3KESBs0Q6wF8CmEYlh0TKgOzyz0lVPqm5plmZv_0MlEFiS27ou8paV5kzBj3rBaldVCdvRNBjKTR8VzTPQkKe4SmsD7I4EmBpyR6ngtKPcEPkd4WRduOez3NzFUcRLSOJ9JxOm1JI/s320/decpdp12.jpg" alt="" id="BLOGGER_PHOTO_ID_5218022768495171378" border="0" /></a><br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >The DEC PDP-12</span><br /></div><br />Sure looks "mini", huh? But we're getting ahead of our story.<br /><br />One of the earliest attempts to build an all-electronic (that is, no gears, cams, belts, shafts, etc.) digital computer occurred in 1937 by J. V. Atanasoff, a professor of physics and mathematics at Iowa State University. By 1941 he and his graduate student, Clifford Berry, had succeeded in building a machine that could solve 29 simultaneous equations with 29 unknowns. This machine was the first to store data as a charge on a capacitor, which is how today's computers store information in their main memory (DRAM or dynamic RAM). As far as its inventors were aware, it was also the first to employ binary arithmetic. However, the machine was not programmable, it lacked a conditional branch, its design was appropriate for only one type of mathematical problem, and it was not further pursued after World War II. It's inventors didn't even bother to preserve the machine and it was dismantled by those who moved into the room where it lay abandoned.<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhon0qENkishqVCa-o6WaHoItsPeHp9DST66H6rRpiq5DnpuCbyyQJGqbzu5W4ai-DWJqOaqgSb8FmlNyP5Ghi84u6x4gSJM8nbc7tKt_HNAajBmPwUTKe1rBY18mIPR9VlLX_0TFKEk8fS/s1600-h/ABC.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhon0qENkishqVCa-o6WaHoItsPeHp9DST66H6rRpiq5DnpuCbyyQJGqbzu5W4ai-DWJqOaqgSb8FmlNyP5Ghi84u6x4gSJM8nbc7tKt_HNAajBmPwUTKe1rBY18mIPR9VlLX_0TFKEk8fS/s320/ABC.jpg" alt="" id="BLOGGER_PHOTO_ID_5218023207314401346" border="0" /></a><br /></div><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >The Atanasoff-Berry Computer [photo © 2002 IEEE]</span><br /></div><div style="text-align: justify;"><br />Another candidate for granddaddy of the modern computer was Colossus, built during World War II by Britain for the purpose of breaking the cryptographic codes used by Germany. Britain led the world in designing and building electronic machines dedicated to code breaking, and was routinely able to read coded Germany radio transmissions. But Colossus was definitely not a general purpose, reprogrammable machine. Note the presence of pulleys in the two photos of Colossus below:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3XMnkU7eet55uFk53b2OQmcaydfNwrUAmd1S4BkHPZejtDAmofQ2a9p6-hnePJiLSHEcAKGYvQ_UsqHGi-Y0StvH2mQZtWd-jVBp0wF24_kZh4nRUohKaop2wjxoVaMOEZfvRPPbmt2dd/s1600-h/Colossus.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3XMnkU7eet55uFk53b2OQmcaydfNwrUAmd1S4BkHPZejtDAmofQ2a9p6-hnePJiLSHEcAKGYvQ_UsqHGi-Y0StvH2mQZtWd-jVBp0wF24_kZh4nRUohKaop2wjxoVaMOEZfvRPPbmt2dd/s320/Colossus.gif" alt="" id="BLOGGER_PHOTO_ID_5218022846324220482" border="0" /></a><br /></div><div style="text-align: center; font-weight: bold;"><span style="color: rgb(0, 102, 0);font-size:85%;" >Two views of the code-breaking Colossus of Great Britain</span><span style="font-size:85%;"><br /></span></div><br /><br /><div style="text-align: justify;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVrihyphenhyphencw1gFXAg9kWodepAgptYaqh4o3Lr7GUL8Anc-7ZPuby3l9lOd0XHeUGnXKBWwgsfmRqEPJm2Tlqm2zNnD3eawHDfkmBlKAiLzdv1Tye-KIE7N5zd6qGazbjfrXdmQW000LpNoPLZ/s1600-h/Colossus2.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVrihyphenhyphencw1gFXAg9kWodepAgptYaqh4o3Lr7GUL8Anc-7ZPuby3l9lOd0XHeUGnXKBWwgsfmRqEPJm2Tlqm2zNnD3eawHDfkmBlKAiLzdv1Tye-KIE7N5zd6qGazbjfrXdmQW000LpNoPLZ/s320/Colossus2.jpg" alt="" id="BLOGGER_PHOTO_ID_5218022976439051490" border="0" /></a><br /></div><div style="text-align: justify;">The Harvard Mark I, the Atanasoff-Berry computer, and the British Colossus all made important contributions. American and British computer pioneers were still arguing over who was first to do what, when in 1965 the work of the German Konrad Zuse was published for the first time in English. Scooped! Zuse had built a sequence of general purpose computers in Nazi Germany. The first, the Z1, was built between 1936 and 1938 in the parlor of his parent's home.<br /></div><div style="text-align: justify;"><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5Lvrf3MYYEyArcjNx-Q0zJkWiYMBe7soUVg5A6svxbh0kwuP0kxV-T9ZW8lsV4D4m1xP20bbtuuiv3P-UVHFFknMJwfAd-EQ795wNiRSycLnCOuSXSyy3HzFaa-Rm9RDLZ8slktpxIycw/s1600-h/Zuse_Z1.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5Lvrf3MYYEyArcjNx-Q0zJkWiYMBe7soUVg5A6svxbh0kwuP0kxV-T9ZW8lsV4D4m1xP20bbtuuiv3P-UVHFFknMJwfAd-EQ795wNiRSycLnCOuSXSyy3HzFaa-Rm9RDLZ8slktpxIycw/s320/Zuse_Z1.jpg" alt="" id="BLOGGER_PHOTO_ID_5218022153419720498" border="0" /></a><br /></div><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >The Zuse Z1 in its residential setting</span><br /></div><div style="text-align: justify;"><br />Zuse's third machine, the Z3, built in 1941, was probably the first operational, general-purpose, programmable (that is, software controlled) digital computer. Without knowledge of any calculating machine inventors since Leibniz (who lived in the 1600's), Zuse reinvented Babbage's concept of programming and decided on his own to employ binary representation for numbers (Babbage had advocated decimal). The Z3 was destroyed by an Allied bombing raid. The Z1 and Z2 met the same fate and the Z4 survived only because Zuse hauled it in a wagon up into the mountains. Zuse's accomplishments are all the more incredible given the context of the material and manpower shortages in Germany during World War II. Zuse couldn't even obtain paper tape so he had to make his own by punching holes in discarded movie film. Because these machines were unknown outside Germany, they did not influence the path of computing in America. But their architecture is identical to that still in use today: an arithmetic unit to do the calculations, a memory for storing numbers, a control system to supervise operations, and input and output devices to connect to the external world. Zuse also invented what might be the first high-level computer language, "Plankalkul", though it too was unknown outside Germany.<br /><br /><br /><span style="font-style: italic;font-size:85%;" ><br />by: http://www.computersciencelab.com/</span><br /><br /></div>qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0tag:blogger.com,1999:blog-6926266186147655709.post-52180679204272979942008-07-01T05:00:00.000-07:002008-07-02T04:21:04.791-07:00<div style="text-align: center; color: rgb(0, 102, 0);"><span style="font-size:130%;">An Illustrated History of Computers<br /></span></div><div style="text-align: justify;"><div style="text-align: center;"><span style="color: rgb(0, 102, 0);font-size:130%;" >Part 2</span><br /></div><br /><div style="text-align: center;">___________________________________<br /></div><div style="text-align: center;"><br /></div><span style="color: rgb(0, 102, 0);font-size:130%;" >J</span>ust a few years after Pascal, the German Gottfried Wilhelm Leibniz (co-inventor with Newton of calculus) managed to build a four-function (addition, subtraction, multiplication, and division) calculator that he called the stepped reckoner because, instead of gears, it employed fluted drums having ten flutes arranged around their circumference in a stair-step fashion. Although the stepped reckoner employed the decimal number system (each drum had 10 flutes), Leibniz was the first to advocate use of the binary number system which is fundamental to the operation of modern computers. Leibniz is considered one of the greatest of the philosophers but he died poor and alone.<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAWb5KbywWDMyCJFuzY8Vi0kvZmvSHluyQKQt2MFMg6qfX-GfCkiyBcgxyUwg135T551kcSXTmKkZpnRNwH7Y4FFonWGF4hpZ2QdK8QfQCkKim8TVrwKEYa-zM3ec3biEZEZWzs0VkhLig/s1600-h/SteppedReckoner.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAWb5KbywWDMyCJFuzY8Vi0kvZmvSHluyQKQt2MFMg6qfX-GfCkiyBcgxyUwg135T551kcSXTmKkZpnRNwH7Y4FFonWGF4hpZ2QdK8QfQCkKim8TVrwKEYa-zM3ec3biEZEZWzs0VkhLig/s320/SteppedReckoner.gif" alt="" id="BLOGGER_PHOTO_ID_5218017586623992050" border="0" /></a><br /><div style="text-align: center;"><span style="font-weight: bold;font-size:85%;" ><span style="color: rgb(0, 102, 0);">Leibniz's Stepped Reckoner (have you ever heard "calculating" referred to as "reckoning"?)</span></span><br /></div><br />In 1801 the Frenchman Joseph Marie Jacquard invented a power loom that could base its weave (and hence the design on the fabric) upon a pattern automatically read from punched wooden cards, held together in a long row by rope. Descendents of these punched cards have been in use ever since (remember the "hanging chad" from the Florida presidential ballots of the year 2000?).<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh45-kiCfuJLePkpW6AyM2_uCSUil1LAPTUnROmZuflUWg9doo_VpHakxfXpcg9c8zueBUQbDgo1UWRylZDAM8hMA6mdyBteg8mqBh4ISp8TOcWV9VqW_v54VgSsOPm8lj3Pl0kAJxsPx94/s1600-h/JacquardLoom.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh45-kiCfuJLePkpW6AyM2_uCSUil1LAPTUnROmZuflUWg9doo_VpHakxfXpcg9c8zueBUQbDgo1UWRylZDAM8hMA6mdyBteg8mqBh4ISp8TOcWV9VqW_v54VgSsOPm8lj3Pl0kAJxsPx94/s320/JacquardLoom.jpg" alt="" id="BLOGGER_PHOTO_ID_5218017250637214706" border="0" /></a><br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0);"><span style="font-weight: bold;font-size:85%;" >Jacquard's Loom showing the threads and the punched card</span>s</span><br /></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-m8mtGGwwrcHw2QTkHXvhZV4QV8NijEmp7TUxMrZ1iVgJqnm-dkbz2Up8dO2D09hu3BhsiIOiHnPAP8ChIRZmi39qk_xwUnLuF11nuM7TQO96tvgmhjXqKAjNx7OkpxDAkYbwNJk7rLZt/s1600-h/JacquardCard.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-m8mtGGwwrcHw2QTkHXvhZV4QV8NijEmp7TUxMrZ1iVgJqnm-dkbz2Up8dO2D09hu3BhsiIOiHnPAP8ChIRZmi39qk_xwUnLuF11nuM7TQO96tvgmhjXqKAjNx7OkpxDAkYbwNJk7rLZt/s320/JacquardCard.jpg" alt="" id="BLOGGER_PHOTO_ID_5218017059418073314" border="0" /></a> <div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >By selecting particular cards for Jacquard's loom you defined the woven pattern [photo © 2002 IEEE]</span><br /><br /></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxRO34xoS8zhVcziYLahzk6MyPIHOPssYQ1P9ACLKn8aCZhH3LQg6jxz4_j7EDjXFA7m2c194A4-lxwTnsMFs0VchSnRVbxb9iwsVnsQJtQtBWfildktLcHbRLmdCyB0BOJzFHw3A4E_x-/s1600-h/jacquardcard.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxRO34xoS8zhVcziYLahzk6MyPIHOPssYQ1P9ACLKn8aCZhH3LQg6jxz4_j7EDjXFA7m2c194A4-lxwTnsMFs0VchSnRVbxb9iwsVnsQJtQtBWfildktLcHbRLmdCyB0BOJzFHw3A4E_x-/s320/jacquardcard.gif" alt="" id="BLOGGER_PHOTO_ID_5218016872061592354" border="0" /></a><br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >A close-up of a Jacquard card</span><br /><br /></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtvXE7uAJY8O8Pc8Bl9mO1xSv-6BRca1ofI5-Oq6eidk2yVuWSbnCoxccKlxZ6fpLWw5bFOLIci4kVVbrt5-DGiIJ2VZeuOnwLlKjEHJPCLjQ3HWVZvL2Fq0GXYZBZBFvkhHOS-RJSbQbU/s1600-h/jacquard.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtvXE7uAJY8O8Pc8Bl9mO1xSv-6BRca1ofI5-Oq6eidk2yVuWSbnCoxccKlxZ6fpLWw5bFOLIci4kVVbrt5-DGiIJ2VZeuOnwLlKjEHJPCLjQ3HWVZvL2Fq0GXYZBZBFvkhHOS-RJSbQbU/s320/jacquard.jpg" alt="" id="BLOGGER_PHOTO_ID_5218016743392239378" border="0" /></a><br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0);"><span style="font-weight: bold;font-size:85%;" >This tapestry was woven by a Jacquard loo</span>m</span><br /></div><br />Jacquard's technology was a real boon to mill owners, but put many loom operators out of work. Angry mobs smashed Jacquard looms and once attacked Jacquard himself. History is full of examples of labor unrest following technological innovation yet most studies show that, overall, technology has actually increased the number of jobs.<br /><br />By 1822 the English mathematician Charles Babbage was proposing a steam driven calculating machine the size of a room, which he called the Difference Engine. This machine would be able to compute tables of numbers, such as logarithm tables. He obtained government funding for this project due to the importance of numeric tables in ocean navigation. By promoting their commercial and military navies, the British government had managed to become the earth's greatest empire. But in that time frame the British government was publishing a seven volume set of navigation tables which came with a companion volume of corrections which showed that the set had over 1000 numerical errors. It was hoped that Babbage's machine could eliminate errors in these types of tables. But construction of Babbage's Difference Engine proved exceedingly difficult and the project soon became the most expensive government funded project up to that point in English history. Ten years later the device was still nowhere near complete, acrimony abounded between all involved, and funding dried up. The device was never finished.<br /><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYR8DugE79njgJrqgkxaNGIg4ZnuP5wYOrjro5WcQPm48bQFIjq19uFGlQ5reLoVDUWNVo26gPI35EEZCF3dd2J963OXXeNMMzpNjuguFLYDxDxILRVowl5pnBA2YsSUzPzICqOJJYt9_S/s1600-h/DifferenceEngine.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYR8DugE79njgJrqgkxaNGIg4ZnuP5wYOrjro5WcQPm48bQFIjq19uFGlQ5reLoVDUWNVo26gPI35EEZCF3dd2J963OXXeNMMzpNjuguFLYDxDxILRVowl5pnBA2YsSUzPzICqOJJYt9_S/s320/DifferenceEngine.jpg" alt="" id="BLOGGER_PHOTO_ID_5218016472884759122" border="0" /></a><br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >A small section of the type of mechanism employed in Babbage's Difference Engine [photo © 2002 IEEE]</span><br /></div><br />Babbage was not deterred, and by then was on to his next brainstorm, which he called the Analytic Engine. This device, large as a house and powered by 6 steam engines, would be more general purpose in nature because it would be programmable, thanks to the punched card technology of Jacquard. But it was Babbage who made an important intellectual leap regarding the punched cards. In the Jacquard loom, the presence or absence of each hole in the card physically allows a colored thread to pass or stops that thread (you can see this clearly in the earlier photo). Babbage saw that the pattern of holes could be used to represent an abstract idea such as a problem statement or the raw data required for that problem's solution. Babbage saw that there was no requirement that the problem matter itself physically pass thru the holes.<br /><br />Furthermore, Babbage realized that punched paper could be employed as a storage mechanism, holding computed numbers for future reference. Because of the connection to the Jacquard loom, Babbage called the two main parts of his Analytic Engine the "Store" and the "Mill", as both terms are used in the weaving industry. The Store was where numbers were held and the Mill was where they were "woven" into new results. In a modern computer these same parts are called the memory unit and the central processing unit (CPU).<br /><br />The Analytic Engine also had a key function that distinguishes computers from calculators: the conditional statement. A conditional statement allows a program to achieve different results each time it is run. Based on the conditional statement, the path of the program (that is, what statements are executed next) can be determined based upon a condition or situation that is detected at the very moment the program is running.<br /><br />You have probably observed that a modern stoplight at an intersection between a busy street and a less busy street will leave the green light on the busy street until a car approaches on the less busy street. This type of street light is controlled by a computer program that can sense the approach of cars on the less busy street. That moment when the light changes from green to red is not fixed in the program but rather varies with each traffic situation. The conditional statement in the stoplight program would be something like, "if a car approaches on the less busy street and the more busy street has already enjoyed the green light for at least a minute then move the green light to the less busy street". The conditional statement also allows a program to react to the results of its own calculations. An example would be the program that the I.R.S uses to detect tax fraud. This program first computes a person's tax liability and then decides whether to alert the police based upon how that person's tax payments compare to his obligations.<br /><br />Babbage befriended Ada Byron, the daughter of the famous poet Lord Byron (Ada would later become the Countess Lady Lovelace by marriage). Though she was only 19, she was fascinated by Babbage's ideas and thru letters and meetings with Babbage she learned enough about the design of the Analytic Engine to begin fashioning programs for the still unbuilt machine. While Babbage refused to publish his knowledge for another 30 years, Ada wrote a series of "Notes" wherein she detailed sequences of instructions she had prepared for the Analytic Engine. The Analytic Engine remained unbuilt (the British government refused to get involved with this one) but Ada earned her spot in history as the first computer programmer. Ada invented the subroutine and was the first to recognize the importance of looping. Babbage himself went on to invent the modern postal system, cowcatchers on trains, and the ophthalmoscope, which is still used today to treat the eye.<br /><br />The next breakthrough occurred in America. The U.S. Constitution states that a census should be taken of all U.S. citizens every 10 years in order to determine the representation of the states in Congress. While the very first census of 1790 had only required 9 months, by 1880 the U.S. population had grown so much that the count for the 1880 census took 7.5 years. Automation was clearly needed for the next census. The census bureau offered a prize for an inventor to help with the 1890 census and this prize was won by Herman Hollerith, who proposed and then successfully adopted Jacquard's punched cards for the purpose of computation.<br /><br />Hollerith's invention, known as the Hollerith desk, consisted of a card reader which sensed the holes in the cards, a gear driven mechanism which could count (using Pascal's mechanism which we still see in car odometers), and a large wall of dial indicators (a car speedometer is a dial indicator) to display the results of the count.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcxR5U1So63ipUk7YBVdSkmKhpTRYYCdbvkY_UdrC6Hj1ibtFZxkEFyYLTK6kDl-CLAwvZY4iFx1KXy91KQVvdeeWEiKe7ndwK5jvKy-e5c4JJjkS9L2NsWvypk2gCKwJId5MgGDU-vSAE/s1600-h/HollerithOperator.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcxR5U1So63ipUk7YBVdSkmKhpTRYYCdbvkY_UdrC6Hj1ibtFZxkEFyYLTK6kDl-CLAwvZY4iFx1KXy91KQVvdeeWEiKe7ndwK5jvKy-e5c4JJjkS9L2NsWvypk2gCKwJId5MgGDU-vSAE/s320/HollerithOperator.jpg" alt="" id="BLOGGER_PHOTO_ID_5218016664297737554" border="0" /></a><br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >An operator working at a Hollerith Desk like the one below</span><br /><br /><br /></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKoSGwBnX15yaMVHp86CPtV7GKko0bslnJKqp3CRPGBDSKbz1qZ-kvaskrI5nzJlOCiqfu9eFTup_5g3Gso9-ec5TD3LEKyg8d0dyBsql4L_o3nTPfdNr6EZPJeW98UNwrsQsHoq5ALCaX/s1600-h/Hollerith.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKoSGwBnX15yaMVHp86CPtV7GKko0bslnJKqp3CRPGBDSKbz1qZ-kvaskrI5nzJlOCiqfu9eFTup_5g3Gso9-ec5TD3LEKyg8d0dyBsql4L_o3nTPfdNr6EZPJeW98UNwrsQsHoq5ALCaX/s320/Hollerith.jpg" alt="" id="BLOGGER_PHOTO_ID_5218016535703637586" border="0" /></a><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEho3lqE-qHWKLOvuCdchYMOWGN2PMQ-uUPW15Bjyxu8PMGyKcoZzctNmuE-oV3NDkmc1Kln1-TcNCuNqe_FVtTfqjctnC0rJfhkfbaY5f7C8WAnaKBCOA2Ww7lVqig0JGnIgTimmZNdH4tW/s1600-h/Census01.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEho3lqE-qHWKLOvuCdchYMOWGN2PMQ-uUPW15Bjyxu8PMGyKcoZzctNmuE-oV3NDkmc1Kln1-TcNCuNqe_FVtTfqjctnC0rJfhkfbaY5f7C8WAnaKBCOA2Ww7lVqig0JGnIgTimmZNdH4tW/s320/Census01.jpg" alt="" id="BLOGGER_PHOTO_ID_5218016391916494370" border="0" /></a><br /><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >Preparation of punched cards for the U.S. census</span><span style="font-weight: bold;font-size:85%;" ><br /></span><br /><br /><br /></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlUL6vYxBnKOdDKrVPpzH4YM3VIVQ5T7UarkGBn1LjQSucq5HjMvzXAzpQoYlEWmKxig6os-QZGzCHvvfJMzSdmI1zxwTFqoywSntf5qSpl84WPwg-zDf7bXGrO-QwepEjj_H3GK7Aqpf4/s1600-h/HollerithDesk.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlUL6vYxBnKOdDKrVPpzH4YM3VIVQ5T7UarkGBn1LjQSucq5HjMvzXAzpQoYlEWmKxig6os-QZGzCHvvfJMzSdmI1zxwTFqoywSntf5qSpl84WPwg-zDf7bXGrO-QwepEjj_H3GK7Aqpf4/s320/HollerithDesk.jpg" alt="" id="BLOGGER_PHOTO_ID_5218016604028322962" border="0" /></a><span style="font-weight: bold;font-size:85%;" ><br /></span><div style="text-align: center;"><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:85%;" >A few Hollerith desks still exist today [photo courtesy The Computer Museum]</span><br /></div><br />The patterns on Jacquard's cards were determined when a tapestry was designed and then were not changed. Today, we would call this a read-only form of information storage. Hollerith had the insight to convert punched cards to what is today called a read/write technology. While riding a train, he observed that the conductor didn't merely punch each ticket, but rather punched a particular pattern of holes whose positions indicated the approximate height, weight, eye color, etc. of the ticket owner. This was done to keep anyone else from picking up a discarded ticket and claiming it was his own (a train ticket did not lose all value when it was punched because the same ticket was used for each leg of a trip). Hollerith realized how useful it would be to punch (write) new cards based upon an analysis (reading) of some other set of cards. Complicated analyses, too involved to be accomplished during a single pass thru the cards, could be accomplished via multiple passes thru the cards using newly printed cards to remember the intermediate results. Unknown to Hollerith, Babbage had proposed this long before.<br /><br />Hollerith's technique was successful and the 1890 census was completed in only 3 years at a savings of 5 million dollars. Interesting aside: the reason that a person who removes inappropriate content from a book or movie is called a censor, as is a person who conducts a census, is that in Roman society the public official called the "censor" had both of these jobs.<br /><br />Hollerith built a company, the Tabulating Machine Company which, after a few buyouts, eventually became International Business Machines, known today as IBM. IBM grew rapidly and punched cards became ubiquitous. Your gas bill would arrive each month with a punch card you had to return with your payment. This punch card recorded the particulars of your account: your name, address, gas usage, etc. (I imagine there were some "hackers" in these days who would alter the punch cards to change their bill). As another example, when you entered a toll way (a highway that collects a fee from each driver) you were given a punch card that recorded where you started and then when you exited from the toll way your fee was computed based upon the miles you drove. When you voted in an election the ballot you were handed was a punch card. The little pieces of paper that are punched out of the card are called "chad" and were thrown as confetti at weddings. Until recently all Social Security and other checks issued by the Federal government were actually punch cards. The check-out slip inside a library book was a punch card. Written on all these cards was a phrase as common as "close cover before striking": "do not fold, spindle, or mutilate". A spindle was an upright spike on the desk of an accounting clerk. As he completed processing each receipt he would impale it on this spike. When the spindle was full, he'd run a piece of string through the holes, tie up the bundle, and ship it off to the archives. You occasionally still see spindles at restaurant cash registers.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvvV7EXlkEa-AwSxXcZuSVzPxhLVGf67dfdFOJL2FaGer3f77SkYYwJ4EobZd3wKUgoPVdv81ly7yFAXXQ1t8mmmj8splbacaTcmFdkq_63EbpomnAWTzRfnHs91rFybqe8TZO2jeGadRX/s1600-h/UnivacCard.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvvV7EXlkEa-AwSxXcZuSVzPxhLVGf67dfdFOJL2FaGer3f77SkYYwJ4EobZd3wKUgoPVdv81ly7yFAXXQ1t8mmmj8splbacaTcmFdkq_63EbpomnAWTzRfnHs91rFybqe8TZO2jeGadRX/s320/UnivacCard.gif" alt="" id="BLOGGER_PHOTO_ID_5218017646575560162" border="0" /></a><br /><div style="text-align: center;"><span style="font-weight: bold;font-size:85%;" ><span style="color: rgb(0, 102, 0);">Two types of computer punch cards</span></span><br /><br /><br /></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi-TvKb6fuhtbPzbsC9GXF1KDHl9U1hkZ9vWoK6ZC2Bt8WNz1fLkb-FxhO0A3Gh4Oy8JzTW_uNeslPtwNs5sRXGLfUS5cemtWARDimlpJDiaehvwVn_3bA29IagDR8j88PyYuaMLhb3fFH1/s1600-h/PunchCard.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi-TvKb6fuhtbPzbsC9GXF1KDHl9U1hkZ9vWoK6ZC2Bt8WNz1fLkb-FxhO0A3Gh4Oy8JzTW_uNeslPtwNs5sRXGLfUS5cemtWARDimlpJDiaehvwVn_3bA29IagDR8j88PyYuaMLhb3fFH1/s320/PunchCard.jpg" alt="" id="BLOGGER_PHOTO_ID_5218017387148547618" border="0" /></a><br /><div style="text-align: center;"><div style="text-align: left;">Incidentally, the Hollerith census machine was the first machine to ever be featured on a magazine cover.<br /></div><br /><br /></div></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_V7BBHA_PNQjH4Xb9-bBf_I7II-H1jw12yIQPn8wM30t4KAMn1V2YAGjglQIevVIzEV1oY6WxeUZDtbU-6xsVshr8QPVGsQmdYE7aUvyp5MeKNfW1_TVMSzHR1JZ0Ga3caplhCN2M137R/s1600-h/ScientificAmericanCover.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_V7BBHA_PNQjH4Xb9-bBf_I7II-H1jw12yIQPn8wM30t4KAMn1V2YAGjglQIevVIzEV1oY6WxeUZDtbU-6xsVshr8QPVGsQmdYE7aUvyp5MeKNfW1_TVMSzHR1JZ0Ga3caplhCN2M137R/s320/ScientificAmericanCover.jpg" alt="" id="BLOGGER_PHOTO_ID_5218017480710147074" border="0" /></a>qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0tag:blogger.com,1999:blog-6926266186147655709.post-76410377051052298272008-06-16T04:32:00.000-07:002008-07-01T04:15:11.079-07:00Networking<b style="font-family: trebuchet ms;">What is a Network?</b> <blockquote style="font-family: trebuchet ms;"> <p>A network is the interconnection of computers for the sharing of information and resources.</p> </blockquote> <p face="trebuchet ms"> <b>Why Network Computers?</b></p> <blockquote style="font-family: trebuchet ms;"> <p>Allow people to share information, software, and any resources, including hardware, more efficiently.</p> </blockquote> <p face="trebuchet ms"> <b>What Networking Can Do?</b></p> <ul style="font-family: trebuchet ms;"><li>Printer sharing </li><li>Printer spooling </li><li>Disk sharing </li><li>File sharing</li></ul> <p face="trebuchet ms"> <b>Why Network Classroom Computers?</b></p> <ul style="font-family: trebuchet ms;"><li>Program security </li><li>Personal work files are much more secure </li><li>Reduced need for floppy disks </li><li>Shared files </li><li>Shared printers </li><li>Shared resources </li><li>Easy maintenance</li></ul><div style="text-align: center;font-family:trebuchet ms;"><span style="font-size:180%;">Administrative networks</span><br /></div><b style="font-family: trebuchet ms;"><br /><br />Using Computers for School Administration</b> <ul style="font-family: trebuchet ms;"><li>Storing student demographic information </li><li>Scheduling students </li><li>Storing school-wide attendance records and generating daily attendance reports </li><li>Storing student achievement records and generating reports for parents </li><li>Generating reports for the State Department of Education<br /></li></ul> <p style="font-family: trebuchet ms;"> <b>Major Benefits of Administrative Networks</b></p> <ul style="font-family: trebuchet ms;"><li>Many people can simultaneously view and edit student records</li><li>Data entry can be more efficient </li><li>Centralized storage of student information </li><li>Backing-up copies of all critical information files is centralized </li><li>Access to productivity software is shared </li><li>Access to expensive peripheral equipment is shared<br /></li></ul> <p style="font-family: trebuchet ms;"> <b>Major Concerns of Using Administrative Networks</b></p> <ul style="font-family: trebuchet ms;"><li>The security of the system </li><li>Input errors are much more difficult to prevent </li><li>Considerable cost </li><li>In-service training for network users<br /></li></ul> <p style="font-family: trebuchet ms;"> <b>Approaches to Implementing an Administrative Network</b></p> <blockquote style="font-family: trebuchet ms;"> <p><i><b>Install an "administration only" network</b></i></p> <ul><li>limited to a relatively small number of people </li><li>security of the information on the network </li><li>user of the network by new users can be phased in </li></ul> <p><b><i>Install a School-Wide network </i></b></p> <ul><li>both administrative and instructional programs will coexist </li><li>allow student performance results to be integrated into the administrative system for record keeping and reporting </li><li>attendance can be viewed and updated from anywhere in the school </li><li>allow electronic communication to everyone in the school </li><li>provide an excellent infrastructure for individualized instruction </li><li>entail a significant leap in sophistication and complexity, and require a great deal of planning<br /> </li></ul> <p>One of the most common mistakes school administrators make is to spend considerable amounts of money on the hardware and software for computerized administration packages, but not to budget for staff training. Training is the key component in the successful implementation of computers in school offices.</p> </blockquote> <div style="text-align: center;font-family:trebuchet ms;"><span style="font-size:180%;"><b>School-Wide Networks</b></span></div><p style="font-family: trebuchet ms;"> </p> <p style="font-family: trebuchet ms;"><br /><b>Why Consider School-Wide Networking?</b></p> <blockquote style="font-family: trebuchet ms;"> <p>A school-wide network can be defined as a network connecting computers throughout the school, providing communication between those computers, and giving each computer access to all of the resources on the network.</p> <ul><li>Access for everyone -- any time, anywhere</li><li>Security and control </li><li>Ease of maintenance </li></ul> </blockquote> <p style="font-family: trebuchet ms;"> <b>Uses for a School-Wide Network</b></p> <ul style="font-family: trebuchet ms;"><li>Networks for student learning </li><li>Network access to the Internet </li><li>Networks for school administration<br /></li></ul> <p style="font-family: trebuchet ms;"> <b>Keys to successful School-Wide Networks</b></p> <ul style="font-family: trebuchet ms;"><li>develop long-term and short-term plans </li><li>involve the school staff </li><li>has a realistic vision </li><li>define goals and objectives </li><li>determine the needs of the users </li><li>focus what should be done, not the technology </li><li>allow future flexibility while meeting present needs </li><li>learn from those who have designed school networks before </li><li>plan for the support for teachers and students, office staff and administrators, and technical support for hardware and software<br /></li></ul> <p style="font-family: trebuchet ms;"> Required Resources for a School-Wide Network</p> <ul style="font-family: trebuchet ms;"><li>hardware </li><li>software </li><li>physical facilities </li><li>furniture </li><li>supplies </li></ul> <div style="text-align: center;font-family:trebuchet ms;"><span style="font-size:180%;"><b>Why do we use networks in school</b></span></div><p style="font-family: trebuchet ms;"> </p> <p style="font-family: trebuchet ms;">Computers have become an important part of today's classrooms. They are an important tool for both teachers and students. An effective way to connect these computers, and everyone using them, is to set up a network. Networks have many uses in an academic setting. </p> <p style="font-family: trebuchet ms;"><b> Shared resources </b> </p> <blockquote style="font-family: trebuchet ms;"> <p>Local connections such as a directly connected printer or resources like printers or file servers<br /> shared over a small LANs </p> </blockquote> <p style="font-family: trebuchet ms;"><b> Inter-Computer Communication </b> </p> <blockquote style="font-family: trebuchet ms;"> <p> Some services such as Usenet News involve communications between computers where no<br /> human operator is involved. </p> </blockquote> <p style="font-family: trebuchet ms;"><b> File transfer and Archives </b> </p> <blockquote style="font-family: trebuchet ms;"> <p> Freeware, shareware, etc. </p> </blockquote> <p style="font-family: trebuchet ms;"><b> Inter-Personal Communication </b> </p> <blockquote style="font-family: trebuchet ms;"> <p> E-mail </p> </blockquote> <p style="font-family: trebuchet ms;"><b> Interactive Communications </b> </p> <span style="font-family:trebuchet ms;"> Chat software: MUDS, MOOs, graphic and 3-D environments, collaborative computing</span> <div style="text-align: center;font-family:trebuchet ms;"><span style="font-size:100%;"><b><br /><span style="font-size:180%;">Advantages of networks</span></b></span></div><p style="font-family: trebuchet ms;"> </p> <p style="font-family: trebuchet ms;">No matter what type of computer equipment you are using, installing a network will make your life as an educator run more smoothly. Current networking software provides many advantages for the educational environment.<br /></p> <p style="font-family: trebuchet ms;"> <b>Program Security </b></p> <ul style="font-family: trebuchet ms;"><li> Store copies of programs in locked, read-only spaces on the server </li><li>Protect program files from unauthorized copying </li><li>Prevent tampering with programs </li></ul> <p style="font-family: trebuchet ms;"> <b>More Secure Personal Work Files </b></p> <ul style="font-family: trebuchet ms;"><li> Save personal work in private spaces on hard disk </li><li>Password protected from inadvertent or malicious copying and/or deletion </li><li>No loss of information from damaged or lost floppy disks </li></ul> <p style="font-family: trebuchet ms;"> <b>Reduced Need for Floppy Disks </b></p> <ul style="font-family: trebuchet ms;"><li> Floppy disks are needed only for archiving old files </li><li>Boot disks may be needed to start up workstations (Remote booting removes the need for boot disks.) </li></ul> <p style="font-family: trebuchet ms;"> <b>Shared Files </b></p> <ul style="font-family: trebuchet ms;"><li> Share data and program files to all network users </li><li>Publicly accessible area to store assignments, tests, clipart, and other files </li><li>No copying of entire class sets of data disks </li></ul> <p style="font-family: trebuchet ms;"> <b>Shared Printers </b></p> <ul style="font-family: trebuchet ms;"><li> Share the cost of printers among all users </li><li>Gain access to different types of printers </li><li>Current networking software has built-in print spooling capabilities </li></ul> <p style="font-family: trebuchet ms;"> <b>Shared Resources </b></p> <ul style="font-family: trebuchet ms;"><li> Share peripheral devices </li><li>Access powerful information resources (CD-ROM drives) </li><li>Network modems to access outside resources <ul><li>Library card catalogues </li><li>Databases from all over the world </li><li>Wire services (newspapers, radio stations, television stations) </li></ul> </li></ul> <p style="font-family: trebuchet ms;"> <b>Easy Maintenance </b></p> <ul style="font-family: trebuchet ms;"><li> Well-planned network meets needs for several years </li><li>Single major task of maintenance of boot disks for workstations</li></ul><br /><div style="text-align: center;"><span style="font-size:180%;"><b><br />Network Media</b></span><br /></div><p style="font-family: trebuchet ms;"> </p> <p style="font-family: trebuchet ms;" align="left"><b>Unshielded Twisted Pair (UTP) Cable</b></p> <p style="font-family: trebuchet ms;" align="center"><img src="http://dragon.ep.usm.edu/%7Eit365/module/Networking/Image/twistpr.gif" height="147" width="217" /></p> <ul style="font-family: trebuchet ms;"><li>consist of two insulated copper wires arranged in a regular spiral pattern to minimize the</li><li>electromagnetic interference between adjacent pairs </li><li>low frequency transmission medium </li><li>low cost, small size, and ease of installation </li><li>limited distance, usually less than 100 meters </li><li>the most popular and is generally the best option for school networks <p>Categories of UTP Cable</p> </li></ul> <blockquote style="font-family: trebuchet ms;"> <blockquote> <p>Category 1 Voice Only (Telephone Wire)<br /> Category 2 Data to 4 Mbps (LocalTalk)<br /> Category 3 Data to 10 Mbps (Ethernet)<br /> Category 4 Data to 20 Mbps (16 Mbps Token Ring)<br /> Category 5 Data to 100 Mbps (Fast Ethernet) </p> </blockquote> </blockquote> <ul style="font-family: trebuchet ms;"><li>Catalog 5 cable is widely used for a 10 Mbps Ethernet network </li><li>10BaseT is the IEEE 802.3i standard specification for 10Mbps Ethernet transmission over UTP (Catalog 3, 4, or 5) cable </li><li>The standard connector for UPT cable is an RJ-45 connector, which looks like a large telephone modular connector </li></ul> <p style="font-family: trebuchet ms;" align="center"><img src="http://dragon.ep.usm.edu/%7Eit365/module/Networking/Image/rj45.gif" height="90" width="80" /><br /></p> <p style="font-family: trebuchet ms;" align="left"> <b>Coaxial (Coax) Cable</b></p> <p style="font-family: trebuchet ms;" align="center"><img src="http://dragon.ep.usm.edu/%7Eit365/module/Networking/Image/coax.gif" height="48" width="244" /></p> <ul style="font-family: trebuchet ms;"><li>like the wire used to connect a TV or VCR </li><li>has an inner conductor surrounded by a braided mesh </li><li>both conductors share a common center axial, hence the term "co-axial" </li><li>bandwidth of up to 400 Mhz </li><li>highly resistant to signal interference </li><li>used for long distance (300-600 meters) </li><li>quite bulky and sometimes difficult to install </li><li>the most common type of connector used with coaxial cables is the BNC (Bayone-Neill-Concelman) connector</li></ul> <p style="font-family: trebuchet ms;" align="center"> <img src="http://dragon.ep.usm.edu/%7Eit365/module/Networking/Image/bnc.gif" height="90" width="80" /></p> <ul style="font-family: trebuchet ms;"><li>has two types of coaxial cable:<br /> <i><b>Thin coaxial cable</b></i> <ul><li>refers to as thinnet </li><li>10Base2 is the IEEE standard for Ethernet running on thin coaxial cable </li><li>the 2 refers to the approximate maximum segment length being 200 meters </li><li>is popular in school networks, especially linear bus networks </li></ul> </li></ul> <blockquote style="font-family: trebuchet ms;"> <p><b><i>Thick coaxial cable </i></b><br /> </p> <ul><li>refers to as thicknet </li><li>10Base5 is the IEEE standard for Ethernet running on thick coaxial cable </li><li>the 5 refers to the approximate maximum segment length being 500 meters </li><li>has an extra protective plastic cover that helps keep moisture away from the center</li><li>conductor </li><li>difficult to bend and install </li><li>used for long distance linear bus networks</li></ul> </blockquote> <p style="font-family: trebuchet ms;"> <b>Fiber Optic</b></p> <p style="font-family: trebuchet ms;" align="center"><img src="http://dragon.ep.usm.edu/%7Eit365/module/Networking/Image/fiber.gif" height="70" width="287" /></p> <ul style="font-family: trebuchet ms;"><li>consist of a center glass core surrounded by several layers of protective materials </li><li>immunity to environmental interference </li><li>greater capacity (bandwidth of up to 2 Gbps) </li><li>used for distances up to 100 kilometers </li><li>carry information at vastly greater speeds </li><li>very expensive </li><li>small size and lighter weight </li><li>difficult to install and modify, require highly skilled installers </li><li>adding additional nodes is difficult </li><li>10BaseF refers to the specifications for fiber optic cable carrying Ethernet signals<br /> </li></ul> <p style="font-family: trebuchet ms;"> <b>Wireless</b><br /></p> <ul><li style="font-family: trebuchet ms;">use high frequency radio signals or infrared light beams to communicate between the workstations and the server </li><li style="font-family: trebuchet ms;">need transciever/antenna to send and receive data </li><li style="font-family: trebuchet ms;">widely used for connecting laptop computers to the LAN </li><li style="font-family: trebuchet ms;">expensive </li><li style="font-family: trebuchet ms;">poor security </li><li style="font-family: trebuchet ms;">slower than LANs using cabling </li><li><span style="font-family:trebuchet ms;">susceptible to electrical interference from lights and radios</span></li></ul><br /><div style="text-align: center;font-family:trebuchet ms;"><span style="font-size:180%;"><b>Topologies</b></span></div><p style="font-family: trebuchet ms;"> </p> <p style="font-family: trebuchet ms;"><span style="font-size:130%;"><b><br /></b></span></p> <p style="font-family: trebuchet ms;" align="left"> <b>Linear Bus (Trunkline)</b></p> <p style="font-family: trebuchet ms;" align="center"><img src="http://dragon.ep.usm.edu/%7Eit365/module/Networking/Image/bus.gif" height="131" width="355" /></p> <ul style="font-family: trebuchet ms;"><li>consist of a main run of cable with a terminator at each end </li><li>the file server, workstations, and peripherals are connected to the linear cable </li><li>easy to connect a node to a linear bus </li><li>less expensive, require less cable </li><li>entire network shuts down if there is a break in the main cable </li><li>difficult to identify the problem if the entire network shuts down<br /> </li></ul> <p style="font-family: trebuchet ms;"> <b>Star</b></p> <p style="font-family: trebuchet ms;" align="center"><img src="http://dragon.ep.usm.edu/%7Eit365/module/Networking/Image/star.gif" height="209" width="360" /></p> <ul style="font-family: trebuchet ms;"><li>each node connected directly to a central network hub or concentrator </li><li>a separate cable connects to each computer, and if one cable breaks, only a single computer should be affected </li><li>the hub or concentrator manages and controls all functions of the network. It also acts as a repeater for the data flow </li><li>easy to install and wire </li><li>no disruptions to the network when connecting or removing devices </li><li>easy to detect network problems </li><li>more expensive, requires a hub and more cable length than a linear bus topology </li><li>all nodes shut down if the hub or concentrator fails </li></ul> <p style="font-family: trebuchet ms;"> <b>Star Wired Ring (Token Ring)</b></p> <p style="font-family: trebuchet ms;" align="center"><img src="http://dragon.ep.usm.edu/%7Eit365/module/Networking/Image/ring.gif" height="229" width="320" /></p> <ul style="font-family: trebuchet ms;"><li>developed by IBM </li><li>employ a special coded message called a token that the operating software passes in sequence to each computer on the network </li><li>created for IBM-compatible computers </li><li>4 or 16 Mbps using twisted pair<br /> </li></ul> <p style="font-family: trebuchet ms;"> <img src="http://dragon.ep.usm.edu/%7Eit365/module/Images/iconround.gif" useimagewidth="" useimageheight="" align="bottom" height="22" width="22" /> <b>Daisy-Chain</b></p> <p style="font-family: trebuchet ms;" align="center"><img src="http://dragon.ep.usm.edu/%7Eit365/module/Networking/Image/daisy.gif" height="120" width="360" /></p> <ul><li style="font-family: trebuchet ms;">similar to a bus, except the electrical signal is routed through each computer as it moves along the line </li><li style="font-family: trebuchet ms;">easy to install </li><li style="font-family: trebuchet ms;">entire network shuts down if there is a problem on a node </li><li style="font-family: trebuchet ms;">mainly used on the Macintosh network </li><li style="font-family: trebuchet ms;">slow </li><li><span style="font-family:trebuchet ms;">not practical in multi-room network installations</span></li></ul><br /><div style="text-align: center;font-family:trebuchet ms;"><span style="font-size:180%;"><b>Network Hardware</b></span></div><p style="font-family: trebuchet ms;"> </p> <p style="font-family: trebuchet ms;"><span style="font-size:130%;"><b><br /></b></span></p> <p style="font-family: trebuchet ms;" align="center"><img src="http://dragon.ep.usm.edu/%7Eit365/module/Networking/Image/hardware.gif" height="236" width="328" /><br /></p> <p style="font-family: trebuchet ms;"> <b>File Server</b><br /></p> <blockquote style="font-family: trebuchet ms;"> <p>A File server is a high capacity computer that provides various resources to the network.<br /> the heart of a network</p> <ul><li>need a very fast computer with a large amount of RAM and storage space, a fast network interface card, and a tape back-up device </li><li>need network operating system such as Novell Netware, Windows NT server, or Apple Share </li><li>control the communication of information between the nodes on a network <br /> </li></ul> </blockquote> <p style="font-family: trebuchet ms;"> <b>Workstations</b><br /></p> <blockquote style="font-family: trebuchet ms;"> <p>A computer in a network is called workstation or client.<br /> </p> <ul><li>a computer connected to a network </li><li>need a network interface card </li><li>not necessarily need floppy disk drives or hard disks since files can be saved on the file server<br /> </li></ul> </blockquote> <p style="font-family: trebuchet ms;"> <b>Network Interface Cards (NICs)</b></p> <p style="font-family: trebuchet ms;" align="center"><img src="http://dragon.ep.usm.edu/%7Eit365/module/Networking/Image/nic.gif" height="127" width="202" /><br /></p> <blockquote style="font-family: trebuchet ms;"> <p>NIC provides the link between your computer and your network.</p> <ul><li>provide the physical connection between the network and the workstation </li><li>most are internal, with the card fitting into an expansion slot inside the computer </li><li>some build on the motherboard </li><li>affect the speed and performance of a network</li><li>three common network interface connections: Ethernet cards, LocalTalk connectors, Token Ring cards</li></ul> </blockquote> <p style="font-family: trebuchet ms;"> <b>Hubs/Concentrators</b><br /></p> <blockquote style="font-family: trebuchet ms;"> <p>A hub is a device whose primary function is to send and receive signals along the network between the nodes connected to it.</p> <ul><li>connect multiple devices to the network </li><li>commonly found in star and star-wired ring topology networks </li><li>entire network shuts down if there is a problem on a hub </li><li>serve as a central meeting place for cables from computers, servers and peripherals </li><li>usually configured with 4, 8, 12, or 24 RJ-45 ports </li></ul> </blockquote> <p style="font-family: trebuchet ms;"> <b>Repeaters</b></p> <blockquote style="font-family: trebuchet ms;"> <p> A repeater is a device that regenerates and amplifies signals to create long-distance networks </p> <ul><li> simply receive, amplify and rebroadcast the signals </li><li>some repeaters provide basic error-checking </li><li>can be separate devices or they can be incorporated into a concentrator </li><li>inexpensive, used to overcome distance limitations<br /> </li></ul> </blockquote> <p style="font-family: trebuchet ms;"> <b>Bridges</b><br /></p> <blockquote style="font-family: trebuchet ms;"> <p>A bridge is a device that links two homogenous packet-broadcast local networks. It accepts all packets from each network addressed to devices on the other, buffers them, and retransmits them to the other network.<br /> </p> <ul><li>connect two or more networks using the same address method or protocol </li><li>can provide some addressing information </li><li>monitor and manage the traffic to maintain optimum performance on both sides of the network</li><li>often used when LANs reach their capacity of nodes</li></ul> </blockquote> <p style="font-family: trebuchet ms;"> <b>Switches<br /> </b> </p> <blockquote style="font-family: trebuchet ms;"> <p>A switch is a high-speed multiport bridge. Today, switches are replacing multiport repeaters or concentrators in a UTP environment. </p> <ul><li>an intelligent hub that maintains a bridging table, keeping track of which hardware addresses are located on which network segment </li><li>more efficient than with any other type of hub</li><li>ability to dedicate bandwidth to each port on the switch</li></ul> </blockquote> <p style="font-family: trebuchet ms;"> <b>Routers</b><br /></p> <p style="font-family: trebuchet ms;">Routers are similar to bridges in that they link two or more physically separate network segments. The network segments linked by a router, however, remain logically separate and can function as independent networks. </p> <ul style="font-family: trebuchet ms;"><li>translate information from one network to another; similar to a super-intelligent bridge </li><li>maintain a map of the network, select the best route for data </li><li>access to more network level knowledge than is available to bridges </li><li>information on source addresses, destination addresses, path distances, and in some cases,</li><li>segment bandwidth and segment status are contained in the router's routing table </li><li>translates local addresses (eg. "spot") into network addresses (eg. 131.44.99.12) </li><li>can translate messages with different addressing methods </li><li>can act as firewalls (many ISP's block traffic at the router level) </li><li>direct signal traffic efficiently </li><li>route messages between any two protocols </li><li>can route messages between linear bus, star, and token ring topologies </li><li>can route messages across fiber optic, coaxial, and twisted-pair cabling</li></ul><br /><div style="text-align: center;"><span style="font-size:180%;"><b>Network Operating System</b></span></div><p style="font-family: trebuchet ms;"> </p> <p style="font-family: trebuchet ms;">A network operating system is a supervisory software program that resides on the server. It controls how the network operates by defining who can use the network and how information and peripherals are shared among users.<br /></p> <p style="font-family: trebuchet ms;"> Novell Netware<br /></p> <ul style="font-family: trebuchet ms;"><li>most popular </li><li>good solution of a PC and Mac network </li></ul> <p style="font-family: trebuchet ms;"> Microsoft Windows NT<br /></p> <ul style="font-family: trebuchet ms;"><li>getting popular </li><li>good solution of PC networks </li><li>easier to set up than Novell Netware<br /> </li></ul> <p style="font-family: trebuchet ms;"> AppleShare<br /></p> <ul style="font-family: trebuchet ms;"><li>Macintosh only </li><li>does not scale to fit a large network<br /> </li></ul><span style="font-family:trebuchet ms;"> UNIX/NFS<br /><br /></span><div style="text-align: center;"><span style="font-size:180%;"><b>Media Access Method</b></span></div><p style="font-family: trebuchet ms;"> </p> <p style="font-family: trebuchet ms;">How computing devices access the network cable and send data is known as the media access method. There are four commonly used media access methods: Ethernet, Token Ring, Local Talk, and FDDI.<br /></p> <p style="font-family: trebuchet ms;"> <b>Ethernet</b><br /></p> <ul style="font-family: trebuchet ms;"><li>most popular media access method </li><li>use access method called CSMA/CD (Carrier Sense Multiple Access/Collision Detection) </li><li>allow for linear bus, star, or tree topologies </li><li>transmit data over UTP, thin-coaxial, thick-coaxial and fiber optic cables at rates of 10 Mbps</li><li>Fast Ethernet supports 100 Mbps, but requires faster hubs and network interface cards </li></ul> <p style="font-family: trebuchet ms;"><b> Token Ring<br /> </b> </p> <ul style="font-family: trebuchet ms;"><li> developed by IBM in the mid 1980s </li><li>use a star-wired ring topology over shielded and unshielded twisted-pair wiring </li><li>a central hub (referred to as a "MAU" Mutlistation Access Unit) is at the center of the ring </li><li>Two versions of Token Ring: 4 Mbps and 16 Mbps </li><li>use a token passing process to circulate packets around the ring. </li><li>more expensive than Ethernet </li><li>good option for PC networks</li></ul> <p style="font-family: trebuchet ms;"> <b>Local Talk</b><br /></p> <ul style="font-family: trebuchet ms;"><li>developed by Apple Computer, Inc. for Macintosh computers </li><li>best suited to small networks of Macs </li><li>allow for linear bus, star, or tree topologies using twisted pair cable </li><li>up to 32 devices (computers, printers, and file server) </li><li>slow, data transmits at only 230 Kbps </li><li>use the CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) process for transmitting data. CSMA/CA is similar to CSMA/CD </li><li>single network can be up to 1,000 feet (305 meters)<br /> </li></ul> <p style="font-family: trebuchet ms;"> <b>FDDI (Fiber Distributed Data Interface)</b><br /></p> <ul style="font-family: trebuchet ms;"><li>ANSI standard </li><li>use fiber optics for speeds of up to 100 Mbps </li><li>use primarily to interconnect two or more LANs, often over long distances </li><li>also employ Token Ring passing process to transmit data; but use a dual counter-rotating ring topology, meaning there are two rings of cable with two tokens circulating in opposite directions </li><li>use a token passing process to circulate packets around the ring </li></ul><br /><div style="text-align: center;"><span style="font-size:180%;"><b>Terminology</b></span></div><p style="font-family: trebuchet ms;"> </p> <p style="font-family: trebuchet ms;"><span style="font-size:130%;"><b><br /></b></span></p> <p style="font-family: trebuchet ms;"><b>10Base2</b> - Ethernet specification for thin coaxial cable, transmits signals at 10 Mbps (megabits per second) with a distance limit of 185 meters per segment. </p> <p style="font-family: trebuchet ms;"><b>10Base5 </b>- Ethernet specification for thick coaxial cable, transmits signals at 10 Mbps (megabits per second) with a distance limit of 500 meters per segment. </p> <p style="font-family: trebuchet ms;"><b>10BaseF</b> - Ethernet specification for fiber optic cable, transmits signals at 10 Mbps (megabits per second) with a distance limit of 1000 meters per segment. <br /><br /> <b>10BaseT</b> - Ethernet specification for unshielded twisted pair cable (category 3, 4, or 5), transmits signals at 10 Mbps (megabits per second) with a distance limit of 100 meters per segment.<br /></p> <p style="font-family: trebuchet ms;"><b>Backbone</b> - A cable to which multiple nodes or workstations are attached. <br /></p> <p style="font-family: trebuchet ms;"><b>Cable</b> - Transmission medium of copper wire or optical fiber wrapped in a protective cover. </p> <p style="font-family: trebuchet ms;"> <b>Coaxial cable</b> - Cable consisting of a single copper conductor in the center surrounded by a plastic layer for insulation and a braided metal outer shield. </p> <p style="font-family: trebuchet ms;"> <b>E-mail</b> - Electronic mail. Messages sent through a computer network; they may also include graphics and files. </p> <p style="font-family: trebuchet ms;"><b>Ethernet</b> - The world's most popular networking system. Designed to run all popular network protocols, Ethernet is used on over 40 million computers worldwide. With a transfer speed of 10 million bits per second. Ethernet is the least expensive high speed LAN alternative. </p> <p style="font-family: trebuchet ms;"><b>FTP</b> - File Transfer Protocol. The Internet protocol (and program) used to transfer files between hosts. </p> <p style="font-family: trebuchet ms;"> <b>Fast ethernet</b> - A new Ethernet standard that supports 100 Mbps using category 5 twisted pair or fiber optic cable. </p> <p style="font-family: trebuchet ms;"><b>Fiber optic cable</b> - A cable, consisting of a center glass core surrounded by layers of plastic, that transmits data using light rather than electricity. It has the ability to carry more information over much longer distances. </p> <p style="font-family: trebuchet ms;"> <b>File server</b> - A computer which contains files that can be used by everyone connected to the network. </p> <p style="font-family: trebuchet ms;"> <b>Hub</b> - A hardware device that contains multiple independent but connected modules of network and internetwork equipment. Hubs can be active (where they repeat signals sent through them) or passive (where they do not repeat but merely split signals sent through them). </p> <p style="font-family: trebuchet ms;"><b>Internet</b> - A global network of networks used to exchange information using the TCP/IP protocol. It allows forelectronic mail and the accessing and retrieval of information from remote sources. </p> <p style="font-family: trebuchet ms;"> <b>LAN</b> - Local Area Network. A network connecting computers in a relatively small area such as a building. </p> <p style="font-family: trebuchet ms;"> <b>mbps </b>- MegaBits per Second. A unit showing the speed of a network. </p> <p style="font-family: trebuchet ms;"> <b>Network interface card (NIC)</b> - A board that provides network communication capabilities to and from a computer. </p> <p style="font-family: trebuchet ms;"> <b>Network operating system (NOS)</b> - Operating system which runs on the file server designed to pass information and communicate between more than one computer. Examples include AppleShare, Novell NetWare, and Windows NT Server. </p> <p style="font-family: trebuchet ms;"><b>Novell</b> - The company which makes Netware, the most commonly used network server software for IBM computers. </p> <p style="font-family: trebuchet ms;"><b>Operating system</b> - the software of a computer which controls the execution of programs. </p> <p style="font-family: trebuchet ms;"><b>Peripheral</b> - A device attached to a computer, I. E. printer, modem, CD-ROM etc. </p> <p style="font-family: trebuchet ms;"> <b>Port </b>- A connection point for a cable. </p> <p style="font-family: trebuchet ms;"><b>RJ-45</b> - Standard connectors used for unshielded twisted-pair cable. </p> <p style="font-family: trebuchet ms;"><b>Repeater </b>- A device used in a network to strengthen a signal as it is passed along the network cable. </p> <p style="font-family: trebuchet ms;"><b>Router</b> - A device which connects two networks and permits packets of information to move between networks only if necessary . </p> <p style="font-family: trebuchet ms;"><b>Server </b>- A computer providing a service to network users. </p> <p style="font-family: trebuchet ms;"><b>Speed of Data Transfer</b> - The rate at which information travels through a network, usually measured in megabits per second.<br /><br /> <b>Terminator </b>- A device that provides electrical resistance at the end of a transmission line. Its function is to absorb signals on the line, thereby keeping them from bouncing back and being received again by the network.<br /><br /> <b>Topology</b> - Physical topology of a network refers to the configuration of cables, computers, and other peripherals. main types of physical topology are: linear bus (backbone), star, star-wired ring, and hybrid. Logical topology is the method used to pass the information betweenworkstations. Examples are: Ethernet, AppleTalk, Token Ring, and TCP/IP.<br /><br /> <b>Twisted pair </b>- Network cabling that consists of four pairs of wires that are manufactured with the wires twisted to certain specifications. Available in shielded and unshielded versions.<br /><br /> <b>WWW </b>- World Wide Web is comprised of millions of documents, stored on computers on the Internet. The documents are all linked together and make up most of the information available on the Internet.<br /><br /> <b>WAN </b>- Wide Area Network. A communications network which connects together a number of local networks.<br /><br /> <b>Workstation</b> - A computer connected to a network which is used by a person to run application programs.<br /></p><span style="font-style: italic;font-size:85%;" ><br /><br />Source: http://dragon.ep.usm.edu/</span>qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0tag:blogger.com,1999:blog-6926266186147655709.post-72716730893582624572008-06-12T05:40:00.000-07:002008-07-01T04:15:26.637-07:00Security, Privacy, and Ethics<p style="font-family:trebuchet ms;"><span style="font-size:100%;"><b>Security</b></span></p> <p style="font-family:trebuchet ms;"><span style="font-size:100%;">Computers can store both public and private data. You ensure that what is stored on your computer is secure you can use a password to protect the material. User names and passwords can also protect the information stored on a computer. When using the Internet, one should use caution when giving out personal information.<br /></span></p> <p style="font-family:trebuchet ms;"><span style="font-size:100%;"><b> </b><b>Information Privacy</b></span> </p> <p style="font-family:trebuchet ms;"><span style="font-size:100%;">Intellectual property is a product someone creates based upon his or her thoughts or ideas. Copyright laws exits to protect those who create an idea or product. When using computers, one must respect the property, rights, and privacy of others.</span> </p><p style="font-family:trebuchet ms;"><span style="font-size:100%;">One of the problems related to privacy is the tendency to regard anything displayed on a computer screen as public information. Although most people, including students, would never pick up and read a document lying on someone else's desk, many people do not hesitate to read someone else's computer screen. As word-processing and other tool software becomes more and more common, we must extend the courtesy of privacy from written documents to material displayed on computer screens or stored on disks.</span> </p><center style="font-family:trebuchet ms;"> <p align="left"><span style="font-size:100%;"><br /></span><span style="font-size:100%;"><b> </b><b>Ethics and the Information Age</b><br /><br /></span></p></center> <p style="font-family:trebuchet ms;"><span style="font-size:100%;">Ethics are the standards of honest, morality, and fairness. These standards relate to using computers. One has a responsibility to respect the property, rights, and privacy of others in the way you use computers. Today in the Information Age, one must follow a code of ethics to respect others properties and others personal information.</span> </p><p style="font-family:trebuchet ms;"><span style="font-size:100%;">The legal aspects of computing are complex and multilayered. Teachers can help society by practicing ethical computer use, avoiding software piracy, and providing direct instruction on ethical computing practices.</span></p><p style="font-family:trebuchet ms;"><span style="font-size:100%;"><br /></span></p><p style="font-family:trebuchet ms;"> </p><center style="font-family:trebuchet ms;"> <p><span style="font-size:100%;"><b>Computer Applications in Education</b></span><!-- #EndEditable --></p> <p><span style="font-size:100%;"><b><br /></b></span></p></center><!-- #BeginEditable "Insert%20text%20here" --> <p style="font-family:trebuchet ms;"><span style="color: rgb(0, 0, 0);font-size:100%;" > <b>Management</b></span><span style="font-size:100%;"><br /></span><span style="font-size:100%;"><br />Computers are used in a variety of ways in the educational field. Computers can be used in school management such as budget, inventory, student records, communications, library circulation, and library public access catalog.<br /><br /></span><span style="color: rgb(0, 0, 0);font-size:100%;" > <b>Learning and Instruction</b></span><span style="font-size:100%;"><br /></span><span style="font-size:100%;"><br />Computer applications can be used in education for learning and for instruction. Instruction and learning can be divided into two major areas, teacher-centered instruction and student-centered learning.</span></p> <p style="font-family:trebuchet ms;"><span style="font-size:100%;">Teacher-centered instruction examined the computer as the object of instruction as well as a tool of instruction and the management of instruction. It is subdivided into the categories of computer literacy, CAI, CMI, and design of teaching materials.</span></p> <p style="font-family:trebuchet ms;"><span style="font-size:100%;">Student-centered learning views the computer as a tool for the student to use to create, access, retrieve, manipulate, and transmit information in order to solve a problem. Understanding the concept of the computer as an information tool relies on accepting the fact that the computer is a productivity tool for the student and the teacher alike.</span></p> <p face="trebuchet ms"><span style="color: rgb(0, 0, 0);font-size:100%;" > <b>Educational Research</b></span><span style="font-size:100%;"><br /><br /></span><span style="font-size:100%;">Computers are used widely in educational research. Educational research includes functions relating to information gathering and processing. The teacher/researcher may examine student performance data in new and revealing ways. Bibliographic citations of studies performed by educators around the world can be acquired and perused from the desktop computer.</span></p><p style="font-family: trebuchet ms;"><span style="font-size:100%;"><br /></span></p><p><span style="font-size:78%;"><br /></span> </p><p><!-- #EndEditable --></p>qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0tag:blogger.com,1999:blog-6926266186147655709.post-55668432067326234562008-06-12T05:38:00.000-07:002008-07-01T04:15:40.435-07:00Maintaining Your Computer System<font style="font-family: trebuchet ms;" size="+3"><b>Maintaining Your Computer System</b></font><br style="font-family: trebuchet ms;"><br style="font-family: trebuchet ms;"><center style="font-family: trebuchet ms;"> <center> <p align="left"><b><font size="+2">General Dos and Don't</font></b> </p></center></center> <blockquote style="font-family: trebuchet ms;"> <p><a name="Do:"></a><b><font size="+1">Do:</font></b> </p></blockquote> <ul style="font-family: trebuchet ms;"><li><font size="+1">Always shut down your computer properly.</font> </li><li><font size="+1">Do regular Scandisk to check the hard disk surface for damage.</font> </li><li><font size="+1">Defragment the hard drive periodically.</font> </li><li><font size="+1">Delete all files and programs you no longer need from your computer.</font> </li><li><font size="+1">Use a anti-virus program to prevent a virus on you computer.</font> </li><li><font size="+1">Back up data to floppy disks or zip disks to ensure you have a copy.</font> <p><a name="Don't:"></a><b><font size="+1">Don't:</font></b> </p> </li><li><font size="+1">Do not eat around the computer.</font> </li><li><font size="+1">Do not drink around the computer.</font> </li><li><font size="+1">Do not use magnets around a computer.</font> </li></ul> <center style="font-family: trebuchet ms;"> <p> </p><center> <center></center> <p align="left"><b><font color="#000000"><font color="#000000"><font size="+1"><img src="http://www.blogger.com/Images/iconround.gif" useimagewidth="" useimageheight="" align="bottom" height="22" width="22"></font></font><font size="+1"> </font></font><font size="+2">Taking Care of disks</font></b> </p></center></center> <blockquote style="font-family: trebuchet ms;"> <p><b><font size="+1">Do:</font></b> </p></blockquote> <center style="font-family: trebuchet ms;"> <div align="left"> <ul><li><font size="+1">Delete all files you no longer need from your disk.</font> </li><li><font size="+1">Use a anti virus program to scan for viruses on a disk.</font> </li><li><font size="+1">Do prevent erasing and recording information on a disk by write-protecting it.</font><br /><br /><center> <div align="left"><b><font size="+1">Don't :</font></b> </div></center></li></ul></div></center> <center style="font-family: trebuchet ms;"> <div align="left"> <ul><li><font size="+1">Do not use magnets around a disk.</font> </li><li><font size="+1">Do not take a disk apart.</font> </li><li><font size="+1">Do not remove the disk while it is in use.</font> </li><li><font size="+1">Do not store in extremely hot or cold locations.</font> </li><li><font size="+1">Do not spill liquids on the disk.</font> </li></ul></div> </center> <div style="font-family: trebuchet ms;" align="left"> <p> </p><center> <center></center> <p align="left"><b><font color="#000000"><font color="#000000"><font size="+1"><img src="http://www.blogger.com/Images/iconround.gif" useimagewidth="" useimageheight="" align="bottom" height="22" width="22"></font></font></font><font size="+2"> Cleaning Hardware </font></b></p></center> <blockquote> <h3><font color="#000000">Follow instructions in the manual or in help files that came with the computer or other hardware devices.</font></h3> <h3><font color="#000000">Before cleaning anything, unplug it from the electrical wall socket.</font></h3> <h3><font color="#000000">When to clean a computer</font></h3> <ol><li><font color="#000000"><font size="+1">Computers do not need to be cleaned too often if they are kept in a clean environment</font></font> </li><li><font color="#000000"><font size="+1">Clean the computer when it looks dirty or when a device (like a mouse) does not work right.</font></font> </li><li><font color="#000000"><font size="+1">The two things that need the most cleaning are the screen and mouse.</font></font> </li></ol></blockquote> <ol><h3><font color="#000000"><font size="+1">Materials needed for cleaning a computer</font></font></h3><ol><li><font color="#000000"><font size="+1">Most cleaning materials can be found in a home or any store</font></font> <ul><li><font color="#000000"><font size="+1">soft lint-free cloths</font></font> </li><li><font color="#000000"><font size="+1">soapy water - a drop or two of dishwashing detergent in a gallon of water</font></font> </li><li><font color="#000000"><font size="+1">cotton swabs</font></font> </li><li><font color="#000000"><font size="+1">eraser</font></font> </li><li><font color="#000000"><font size="+1">water spray bottle to hold the soapy water</font></font> </li><li><font color="#000000"><font size="+1">used fabric softener cloth</font></font> </li></ul> </li><li><font color="#000000"><font size="+1">You may have to buy the following at a computer or office supply store</font></font> <ul><li><font color="#000000"><font size="+1">floppy disk drive cleaner kit </font></font> </li><li><font color="#000000"><font size="+1">CD-ROM drive cleaner kit</font></font> </li><li><font color="#000000"><font size="+1">compressed air<br /><br /></font></font></li></ul></li></ol><h3><font color="#000000"><font size="+1">Cleaning the case and other plastic surfaces</font></font></h3><ol><li><font color="#000000"><font size="+1">Use a damp lint-free cloth to clean the case</font></font> <ul><li><font color="#000000"><font size="+1">Spray the water on the cloth. NEVER SPRAY WATER ON A COMPUTER OR OTHER ELECTRICAL DEVICES!</font></font> </li><li><font color="#000000"><font size="+1">Wipe the surfaces with the damp cloth.</font></font> </li></ul> </li><li><font color="#000000"><font size="+1">For more difficult marks use the eraser. An ink eraser works best.</font></font> </li><li><font color="#000000"><font size="+1">For cracks and tight places, use a slightly damp cotton swab.<br /><br /></font></font></li></ol><h3><font color="#000000"><font size="+1">Cleaning a monitor's screen</font></font></h3><ol><li><font color="#000000"><font size="+1">Wipe the screen with the damp lint-free cloth</font></font> </li><li><font color="#000000"><font size="+1">Use a dry cloth to dry the screen</font></font> </li><li><font color="#000000"><font size="+1">You may want to use a used fabric softener cloth to help remove static charges on the screen</font></font> <ul><li><font color="#000000"><font size="+1">static charges attract dust to the screen</font></font> </li><li><font color="#000000"><font size="+1">a fabric softener cloth has anti-static chemicals on it</font></font> </li><li><font color="#000000"><font size="+1">wipe the screen very lightly with the used fabric softener cloth</font></font> </li><li><font color="#000000"><font size="+1">Do not use a fresh fabric softener cloth. It will leave streaks.<br /><br /></font></font></li></ul></li></ol><h3><font color="#000000"><font size="+1">Cleaning the keyboard</font></font></h3><ol><li><font color="#000000"><font size="+1">Use a slightly damp cotton swab to clean in-between the keys</font></font> </li><li><font color="#000000"><font size="+1">Wipe the outside of the keyboard with a damp cloth</font></font> </li><li><font color="#000000" size="+1">U</font><font color="#000000"><font size="+1">se compressed air to remove paper pieces and dust from under the keys</font></font> </li><li><font color="#000000"><font size="+1">Do not take a keyboard apart to clean it!<b> </b>You may not get it back together again.<br /><br /></font></font></li></ol><h3><font color="#000000"><font size="+1">Cleaning a mouse</font></font></h3><ol><li><font color="#000000"><font size="+1">Clean the outside of the mouse with a damp cloth</font></font> </li><li><font color="#000000"><font size="+1">To clean the inside of the mouse</font></font> <ul><li><font color="#000000"><font size="+1">Take the mouse apart</font></font> <ul><li><font color="#000000"><font size="+1">turn the mouse upside down</font></font> </li><li><font color="#000000"><font size="+1">rotate the retaining ring until it comes free<br /></font></font></li></ul> <ul><li><font color="#000000"><font size="+1">turn the mouse right-side up and catch the ring and ball in your hand</font></font> </li></ul> </li><li><font color="#000000"><font size="+1">Use damp cotton swabs to clean the rollers inside the mouse. Be sure to rotate the rollers to get all of the dirt off of them.</font></font> </li><li><font color="#000000"><font size="+1">Wash the ball in warm soapy water. Wipe dry with a lint-free cloth</font></font> </li><li><font color="#000000"><font size="+1">Blow out the inside of the mouse to remove any dust</font></font> </li><li><font color="#000000"><font size="+1">Put the mouse back together after it has dried<br /><br /></font></font><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBbeHhwkW2vVGUYyB0as_estBXZ6dfWSKBshmq6TeAkN10y_wFRgW9uiRdhRbQYSPCQJVxmJgbV-n_y14X9cynI8c3q8XEkTM3Rivw8yrHSse0bWa17HPdQBz_KFSWtY6TH7Le39axo1zu/s1600-h/mocln.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBbeHhwkW2vVGUYyB0as_estBXZ6dfWSKBshmq6TeAkN10y_wFRgW9uiRdhRbQYSPCQJVxmJgbV-n_y14X9cynI8c3q8XEkTM3Rivw8yrHSse0bWa17HPdQBz_KFSWtY6TH7Le39axo1zu/s320/mocln.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210973794790183010" border="0"></a><font color="#000000"><font size="+1"><br /><br /></font></font></li></ul></li></ol><h3><font color="#000000"><font size="+1">Inside the computer's case</font></font></h3><ol><li><font color="#000000"><font size="+1">The inside of the computer rarely has to be cleaned and it is not recommended that this be done</font></font> </li><li><font color="#000000"><font size="+1">If you must clean inside your computer follow the following precautions</font></font> <ul><li><font color="#000000"><font size="+1">Be very careful. You can easily damage the computer or hurt yourself.</font></font> </li><li><font color="#000000"><font size="+1">Do not touch the chips or other electrical components</font></font> </li><li><font color="#000000"><font size="+1">Use a vacuum cleaner to remove dust carefully</font></font> </li><li><font color="#000000"><font size="+1">Use compressed air or the blower option on a vacuum cleaner to blow out dust and other particles<br /><br /></font></font></li></ul></li></ol><h3><font color="#000000"><font size="+1">Floppy disk drives and other drives with removable media</font></font></h3><ol><li><font color="#000000"><font size="+1">Follow the instructions on the cleaning kit.</font></font> </li><li><font color="#000000"><font size="+1">Do not clean your drives too often, especially the floppy disk drive. The cleaning disk is slightly abrasive and can wear down the drivers read/write heads.</font></font> </li></ol></ol></div><!-- #EndEditable -->qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0tag:blogger.com,1999:blog-6926266186147655709.post-65083263588280320982008-06-12T05:26:00.000-07:002008-07-01T04:15:55.899-07:00Software<span style="font-family: trebuchet ms;color:#000000;" ><span style="font-size:+1;"><b><span style="font-size:+2;">Software -- General Information</span></b></span></span> <p style="font-family: trebuchet ms;"><span style="font-size:+1;"><br />Computer software provides instruction that tell the computer how to operate.</span> </p><ul style="font-family: trebuchet ms;"><ol><li><span style="color:#000000;"><span style="font-size:+1;">Software are also called programs.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Programs are usually created using other software called programming languages.<br /></span></span></li></ol></ul> <h3 style="font-family: trebuchet ms;"><span style="color:#000000;"><span style="font-size:+1;">There are two (2) main types of software</span></span></h3> <ol style="font-family: trebuchet ms;"><li><span style="color:#000000;"><span style="font-size:+1;">System Software</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Used by the computer to accomplish a task.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">What system software does:</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">controls the internal function of the computer</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">controls other devices connected to the CPU<br /><br /></span></span></li></ul></li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Application Software</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Used by people to accomplish a specific task.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Some common kinds of application software</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Word Processor software</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Database software</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Spreadsheet software</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Games</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Web Page Browsers<br /></span></span></li></ul></li></ul></li></ol> <h3 style="font-family: trebuchet ms;"><span style="color:#000000;"><span style="color:#000000;"><span style="font-size:+1;"><b><img src="http://www.blogger.com/Images/iconround.gif" height="22" width="22" /> </b></span><span style="font-size:+1;"><b><span style="font-size:+2;">Kinds of Software</span></b></span></span></span></h3> <ol style="font-family: trebuchet ms;"><li><span style="color:#000000;"><span style="font-size:+1;">Public Domain Software</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Has no copyright - no one owns the right to control who can make copies of the software.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Free to use or make copies of.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Can be copied, used in other programs, or changed by anyone.<br /><br /></span></span></li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Freeware</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Has a copyright - someone owns the right to determine who can make copies of the software.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Free to use and make copies of.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Can only give away exact copies of the software.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Can not be changed or used in another program without the copyright holder's permission.<br /><br /></span></span></li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Shareware</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Has a copyright.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Allowed to use the software before paying for it.</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Can be a demo - which limits some major features like the Save command.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Can set an amount of time you can use the software.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Can trust that you will pay for it if you like the software.</span></span> </li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Can only give away exact copies of the software.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Can not be changed or used in another program without the copyright holder's permission.<br /><br /></span></span></li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Commercial Software</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Has the most resistive copyright.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Have to buy the software before you can use it.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Can usually make one copy of the software as a backup copy.</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">A backup copy is used in case something goes wrong with the original software.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Can not give away or sell the backup copy.</span></span> </li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Can not copy, look at the program's code, change, or use the software in another program without the copyright holder's permission.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Commercial Software is the best software in the world.<br /></span></span></li></ul></li></ol> <h3 style="font-family: trebuchet ms;"><span style="color:#000000;"><span style="color:#000000;"><span style="color:#000000;"><span style="font-size:+1;"><b><img src="http://www.blogger.com/Images/iconround.gif" height="22" width="22" /> </b></span><span style="font-size:+1;"><b><span style="font-size:+2;">How Software is Inputted Into Computer</span></b></span></span></span></span></h3> <ol style="font-family: trebuchet ms;"><li><span style="color:#000000;"><span style="font-size:+1;">Built into the computer's circuits, the ROM chips.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Loaded into the computer from a secondary storage device, like a floppy disk or hard disk drive.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Typed in from the keyboard.</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Usually need to use a programming language to create the software.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Rarely done by most computer users today.</span></span> </li></ul></li></ol> <p style="font-family: trebuchet ms;"><span style="color:#000000;"><span style="color:#000000;"><span style="font-size:+1;"><b><img src="http://www.blogger.com/Images/iconround.gif" height="22" width="22" /> </b></span><span style="font-size:+1;"><b><span style="font-size:+2;">System Software</span></b></span></span></span><br /><br /></p><p style="font-family: trebuchet ms;"><a name="System"></a><span style="font-size:+1;"><b>System software</b> is a type of program that acts like a conductor in an orchestra. It directs all the activities and sets all the rules for how the hardware and software work together. MS DOS and Microsoft Windows are examples of system software or operating system software.</span> </p><p style="font-family: trebuchet ms;" align="center"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgAiWL20k7YVMmIq5XQvu5Gf1u8bdvVkY3GJ0I-WmXNS9Uqke3JpahXg1_umK5BHV3vzW7wl8qlfENE9eYIKSu563W0kj_G7ZTjApCSTk8cPMavXl89yVshC5XhG574DtTOdBsRieiXrGoy/s1600-h/macos9.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 127px; height: 125px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgAiWL20k7YVMmIq5XQvu5Gf1u8bdvVkY3GJ0I-WmXNS9Uqke3JpahXg1_umK5BHV3vzW7wl8qlfENE9eYIKSu563W0kj_G7ZTjApCSTk8cPMavXl89yVshC5XhG574DtTOdBsRieiXrGoy/s320/macos9.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210971276864111634" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhE13cTne-u_a0ozDcJMuTqhsQexY8w4bW_-26Y1OYYIrxdQaKtQfE27GqbgxxvhCeQVMi-8J7roNK3cYca1b6sOizkx_h19CdfMDuZm7Lax5KuR0FGgxpaSfDT4ySDg9rKFBIiHtyv5Tyt/s1600-h/Win2000.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhE13cTne-u_a0ozDcJMuTqhsQexY8w4bW_-26Y1OYYIrxdQaKtQfE27GqbgxxvhCeQVMi-8J7roNK3cYca1b6sOizkx_h19CdfMDuZm7Lax5KuR0FGgxpaSfDT4ySDg9rKFBIiHtyv5Tyt/s320/Win2000.gif" alt="" id="BLOGGER_PHOTO_ID_5210971147309398898" border="0" /></a> </p><blockquote style="font-family: trebuchet ms;"> <h3><span style="color:#000000;">Some System Software is built into the computer.</span></h3> <ol><li><span style="color:#000000;"><span style="font-size:+1;">ROM chips and BIOS.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Helps to setup the computer and start it.</span></span> </li></ol></blockquote> <blockquote style="font-family: trebuchet ms;"> <h3><span style="color:#000000;"><span style="font-size:+1;">Operating Systems</span></span></h3> <ol><li><span style="color:#000000;"><span style="font-size:+1;">The operating system is usually located on a disk.</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Can be on either the hard disk drive, a floppy disk, or CD-ROM disk.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Must be loaded into RAM before it can be used.<br /><br /></span></span></li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Used by the computer's hardware to work with its parts.</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Tells the computer how to:</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">display information on the screen.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">use a printer.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">store information on a secondary storage device.</span></span> </li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">The system software that controls peripherals are called drivers.<br /><br /></span></span></li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">An operating system works with application software.</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Does basic tasks, like printing a document or saving a file</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">The operating system starts (launches) the application software so that it can be used.</span></span> </li></ul></li></ol> <h3><span style="color:#000000;"><span style="font-size:+1;">User Interfaces</span></span></h3> <ol><li><span style="color:#000000;"><span style="font-size:+1;">The user interface is how the computer's operating system presents information to the user and the user gives instructions (commands) to the computer.<br /><br /></span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">There are two kinds of User Interfaces</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Text Interface</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Presents information to the user in the form of text.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Have to type in commands or select commands from a menu displayed as text on the screen.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Hard to use or learn, because the user must memorize and type in commands.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Examples:</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">MS-Dos (MicroSoft Disk Operating System)</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">ProDos (Professional Disk Operating System)</span></span> </li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Many of the Text Interfaces had shells placed over them.</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">A shell was more of a Graphic User Interface.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Made using the Text Interface easier to use.</span></span> </li></ul></li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Graphic User Interface (GUI)</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Presents information to the use in the form of pull-down menus and icons.</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Pull-down menus the user clicks on to display the menu</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Icons are small pictures that stand for something, like a file, volume, trash, or program</span></span> </li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">The user gives commands to the computer by selecting items from a menu or by clicking on an icon when using a pointing device.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">GUIs are easy to learn and use</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Examples:</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Windows 98</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Windows 2000 </span></span> </li><li><span style="font-size:+1;"><span style="color:#000000;">MacOS</span><span style="color:#003399;"> </span></span><br /></li></ul></li></ul></li></ul></li></ol></blockquote> <p style="font-family: trebuchet ms;"><span style="color:#000000;"><span style="color:#000000;"><span style="font-size:+1;"><b><img src="http://www.blogger.com/Images/iconround.gif" height="22" width="22" /> </b></span><span style="font-size:+1;"><b><span style="font-size:+2;">Application Software</span></b></span></span></span> </p><p style="font-family: trebuchet ms;" align="center"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTBKRS4bBjOu-X8a0RAEn1S_HlejoiHmb7pK4mwrDgX1DXnVfCa1URnxsevlMRhux6GcRlB9uVG0Jqd-XHdKerib3lqSUVLa0WgizOfnr60w3GRVB2b0L_Awg1_n8pLPgL2YOyB7VRvrfj/s1600-h/office.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTBKRS4bBjOu-X8a0RAEn1S_HlejoiHmb7pK4mwrDgX1DXnVfCa1URnxsevlMRhux6GcRlB9uVG0Jqd-XHdKerib3lqSUVLa0WgizOfnr60w3GRVB2b0L_Awg1_n8pLPgL2YOyB7VRvrfj/s320/office.gif" alt="" id="BLOGGER_PHOTO_ID_5210973102875208898" border="0" /></a> </p><p style="font-family: trebuchet ms;"><a name="Application"></a><span style="font-size:+1;"><b>Application software</b> programs work with the operating system software to help you use your computer to do specific types of work such as word processing to type a letter.</span> </p><ul style="font-family: trebuchet ms;"><ol><li><span style="color:#000000;"><span style="font-size:+1;">Used by people to solve general problems</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Can be used to do more than one thing - adapted to a wide variety of tasks</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Some common tasks done by general purpose application software</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Planning</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Writing</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Record keeping</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Calculating</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Communicating</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Drawing</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Painting</span></span> </li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">What can be done with general purpose application software is only limited by the imagination of the user.<br /><br /></span></span></li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Examples of general purpose application software</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Word Processing Software </span></span><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgktKouqE_-TbwtnQBreN1Eys-QALPUodCumJLhHgZnkjRkoee2aoYFqIa1pHAXhW7fqSjsRFBfestmi8a5-pJwo67aD5bq2XKLhEBLJZwSS-DxVuLU7GkHlxxsOXqe9dEYpuv7SYgHk5O3/s1600-h/word.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 98px; height: 122px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgktKouqE_-TbwtnQBreN1Eys-QALPUodCumJLhHgZnkjRkoee2aoYFqIa1pHAXhW7fqSjsRFBfestmi8a5-pJwo67aD5bq2XKLhEBLJZwSS-DxVuLU7GkHlxxsOXqe9dEYpuv7SYgHk5O3/s320/word.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210971436842905810" border="0" /></a><br /></li><li><span style="color:#000000;"><span style="font-size:+1;">Database Software<br /></span></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6MQ3VMyKlpQXNet9u_Jb294KaEh0uFlpypO4GbjO-M4xa52d3HrAGt0p_VSX_a6bTjGnWaDbeO9WN0EhDJgYuDZFjpggWqzcL1jgCLMaX7IqvbfGf3AJU_G5RXdqBBGvz3myS8lqAZEuA/s1600-h/filemaker.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6MQ3VMyKlpQXNet9u_Jb294KaEh0uFlpypO4GbjO-M4xa52d3HrAGt0p_VSX_a6bTjGnWaDbeO9WN0EhDJgYuDZFjpggWqzcL1jgCLMaX7IqvbfGf3AJU_G5RXdqBBGvz3myS8lqAZEuA/s320/filemaker.gif" alt="" id="BLOGGER_PHOTO_ID_5210971834998388306" border="0" /></a><br /></li><li><span style="color:#000000;"><span style="font-size:+1;">Spreadsheet Software<br /></span></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTs9Ky069TBucOb5yzIEu64iDT4FhyIJqEwNNkYiLqwBbOihS2mZQaVKvJDVxWht5WCbH_T4HPIIHDEDOYpmR7pABzTsMV7iCtqwzHHBOXoynfhedZ_fC3ojdX55nEhD3fJkwRuP5DkG-e/s1600-h/excel.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 102px; height: 144px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTs9Ky069TBucOb5yzIEu64iDT4FhyIJqEwNNkYiLqwBbOihS2mZQaVKvJDVxWht5WCbH_T4HPIIHDEDOYpmR7pABzTsMV7iCtqwzHHBOXoynfhedZ_fC3ojdX55nEhD3fJkwRuP5DkG-e/s320/excel.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210971987598328850" border="0" /></a><br /></li><li><span style="color:#000000;"><span style="font-size:+1;">Desktop Publishing Software<br /></span></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsWQYSvwqMEqRZJDMmQBp9bJ9gT8dVuDO9Uyq9JyDhAYPeom63N53L6uC4Gbr2xwU-u_2D0IqejYLZb6o42MFPZaUbnCCwq9GOWrR2wAzTWTYw8uBTLaFn0JoxOkwOsMxJazltTG7zWpRn/s1600-h/pagemaker.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 104px; height: 106px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsWQYSvwqMEqRZJDMmQBp9bJ9gT8dVuDO9Uyq9JyDhAYPeom63N53L6uC4Gbr2xwU-u_2D0IqejYLZb6o42MFPZaUbnCCwq9GOWrR2wAzTWTYw8uBTLaFn0JoxOkwOsMxJazltTG7zWpRn/s320/pagemaker.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210972162828878034" border="0" /></a><br /></li><li><span style="color:#000000;"><span style="font-size:+1;">Paint and Draw Software </span></span> </li></ul></li></ol></ul><a style="font-family: trebuchet ms;" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXMcRdo4AcwPHx6Ry88X_YJMmdt3E3eUGb17GZBaalf9VY6cnjRMDJALOziGct0zDBkj3Ox3CdCcFQVordz-0qd5XYOqrxHPFH4x0v8Bcks7WfE-aylidxwZvA-Q0s4RW8WpA_PCtaQxSy/s1600-h/paint.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 129px; height: 112px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXMcRdo4AcwPHx6Ry88X_YJMmdt3E3eUGb17GZBaalf9VY6cnjRMDJALOziGct0zDBkj3Ox3CdCcFQVordz-0qd5XYOqrxHPFH4x0v8Bcks7WfE-aylidxwZvA-Q0s4RW8WpA_PCtaQxSy/s320/paint.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210972274544272434" border="0" /></a> <p style="font-family: trebuchet ms;"><span style="color:#000000;"><span style="color:#000000;"><span style="font-size:+1;"><b><img src="http://www.blogger.com/Images/iconround.gif" height="22" width="22" /> </b></span><span style="font-size:+1;"><b><span style="font-size:+2;">Utilities</span></b></span></span></span> </p><p style="font-family: trebuchet ms;" align="left"><a name="Utilites"></a><span style="font-size:+1;"><b>Utilities </b>allow you to complete certain tasks on your computer. Examples of some of these tasks are file organizations.</span> </p><ul style="font-family: trebuchet ms;"><li><span style="color:#000000;"><span style="font-size:+1;">Specific purpose application software used to help a computer work better or to avoid problems.</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Some utility programs are built into the operating system</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Scandisk in the Windows operating system</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Disk formatting software</span></span> </li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Examples of utility programs</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Anti-virus software</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Disk maintenance software </span></span> </li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">File management programs</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">Security software</span></span> </li></ul> <p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaBCRF2zJEd5eWCB0qSAS_6kqDletaETG-H21Kzo8OOyo4QYEs8z82fNpdt7xn_ze7ykBVL89t-r59scSPH1_TxV_HrqXykcYmxaEPzU1SahUStOLH3Gk78AJfbPPXuP7yteZ4BxhqQpPV/s1600-h/norton.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaBCRF2zJEd5eWCB0qSAS_6kqDletaETG-H21Kzo8OOyo4QYEs8z82fNpdt7xn_ze7ykBVL89t-r59scSPH1_TxV_HrqXykcYmxaEPzU1SahUStOLH3Gk78AJfbPPXuP7yteZ4BxhqQpPV/s320/norton.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210972409519986370" border="0" /></a> <!-- #EndEditable --></p>qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0tag:blogger.com,1999:blog-6926266186147655709.post-64504470803729039692008-06-12T05:24:00.001-07:002008-07-01T04:16:08.207-07:00Communication Devices<div style="text-align: justify;"><span style="font-size:+1;"><span style="font-family: trebuchet ms;">Communication Devices<br /><br />Specific equipment and programs are needed to connect to the Internet or to communicate with other computers. You can use any type of computer such as IBM compatible or Macintosh to connect to the Internet or communicate with other computers. You need special programs to use the Internet. Most companies that connect you to the Internet provide the programs you need free of charge. You also need a modem to connect to the Internet. A modem translates computer information into a form that can be transmitted over telephone lines. Modems can be used to</span> connect you to the Internet, exchange information, and to send and receive faxes.<br /><br />Peripheral Devices<br /><br /></span><span style="font-size:+1;">A peripheral devices is any piece of hardware attached to a computer. A few examples of peripheral devices are printers, scanners, and digital cameras.</span><br /><!-- #EndEditable --><br /><!-- #EndEditable --> </div><center> <p> </p></center>qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0tag:blogger.com,1999:blog-6926266186147655709.post-46469331770030126842008-06-12T05:18:00.000-07:002008-07-01T04:16:19.501-07:00Storage Devices<span style="color:#000000;"><span style="font-size:+1;"><b>Storage Devices</b></span></span><p style="font-family: trebuchet ms;"><span style="color:#000000;"><span style="font-size:+1;"><b>How a computer stores information</b></span></span></p> <ul style="font-family: trebuchet ms;"><ol><li><span style="color:#000000;"><span style="font-size:+1;">The computer stores information as a string of zeros (0) and ones (1)</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">The standard string length is eight 0's or 1's in a row</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">This standard length is called a byte</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">A byte equals one character</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">A character is a letter, number, or symbol - it is about any thing that can be typed on a keyboard</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">There are 256 standard characters used by almost all computers<br /><br /></span></span></li></ul></li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Information size measurements</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">Kilobyte (KB)</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">One kilobyte equals about 1024 bytes</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">1KB is about 140 words, about a half page of typed double-spaced text (words only)</span></span> </li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Megabyte (MB)</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">One megabyte equals about 1000 KB</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">One megabyte equals about 1,000,000 bytes</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">One megabyte equals about 500 pages of text, or one large book</span></span> </li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Gigabyte (GB)</span></span> <ul><li><span style="color:#000000;"><span style="font-size:+1;">One gigabyte equals about 1000 MB</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">One gigabyte equals about 1,000,000 KB</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">One gigabyte equals about 1,000,000,000 bytes</span></span> </li><li><span style="color:#000000;"><span style="font-size:+1;">One gigabyte equals over 1,000 books of text</span></span> </li></ul></li></ul></li></ol></ul> <center style="font-family: trebuchet ms;"> <p align="left"><span style="color:#000000;"><span style="font-size:+1;"><b><img src="http://www.blogger.com/Images/iconround.gif" height="22" width="22" /> </b></span><span style="font-size:+1;"><b>Some Common Storage Devices<br /><br /></b></span></span></p></center> <blockquote style="font-family: trebuchet ms;"> <div align="left"><b><span style="font-size:+1;color:#000000;">Hard Drive</span></b> </div> <p><span style="color:#000000;"><span style="font-size:+1;">The hard drive is the primary device that a computer uses to store information. The hard drive stores programs, data files, saves files, and organizes files. The hard drive is located inside the computer case. The hard drive, magnetically stores data on stacks of rotating disks called platters.</span></span> </p></blockquote> <div style="font-family: trebuchet ms;" align="center"><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgY7P5qA4uVvUAq4jpKZSL3L7zM9YLoU7VjXGSC0rOsGHcDl6iJKSIfgwKTE5KadeRb9FoVCoyQm6164uwH3HdtVMpNWQL_fVa77ARrpA1YF3_B6QnOkpSPP7huYcJKt6ZyZi7yiTp2xPrn/s1600-h/harddisk.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgY7P5qA4uVvUAq4jpKZSL3L7zM9YLoU7VjXGSC0rOsGHcDl6iJKSIfgwKTE5KadeRb9FoVCoyQm6164uwH3HdtVMpNWQL_fVa77ARrpA1YF3_B6QnOkpSPP7huYcJKt6ZyZi7yiTp2xPrn/s320/harddisk.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210969025226963186" border="0" /></a><br /><br /></div> <blockquote style="font-family: trebuchet ms;"> <p><b><span style="color:#000000;"><span style="font-size:+1;">Floppy Drive</span></span></b> </p> <p><span style="color:#000000;"><span style="font-size:+1;">The floppy drive stores and retrieves information on a floppy disk.</span></span><br /><br /></p><center><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-vantePQWR9NPibf4tYwg_bgud5r31y5fG5i1ZSHMLneubypkyuJR4ir_B1LWjCZRw1l1IP-rGDZEHJtyzc7FaE2bPSaPHIUdmPw-P2krhwgcK_teNBEiY9iVfGZWp0AeZCPnfZYSJiLq/s1600-h/3_5.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-vantePQWR9NPibf4tYwg_bgud5r31y5fG5i1ZSHMLneubypkyuJR4ir_B1LWjCZRw1l1IP-rGDZEHJtyzc7FaE2bPSaPHIUdmPw-P2krhwgcK_teNBEiY9iVfGZWp0AeZCPnfZYSJiLq/s320/3_5.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210969183543195506" border="0" /></a><br /><br /></center><b><span style="font-size:+1;"><span style="color:#000000;">CD -ROM Drive</span></span> </b> <p><span style="color:#000000;"><span style="font-size:+1;">CD-ROM is a device that reads information stored on a compact disc. CD-ROM stands for Compact Disc Read Only Memory. One CD is equal to the space in over 40 floppy disc.</span></span> </p></blockquote> <div style="font-family: trebuchet ms;" align="center"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgin-3POpRRjcr1HJpDN-c2KPJkCRQNfmOBPs_qIt4RAWpVajJtuWNC1EF3c1G81zEhAMoxP1X9clkfUD05dQojZLuwHGMnQR_uZhKaJk02fVMX_TxXEbgaWGNVDmH-2_wz9h-S1nXNVMoF/s1600-h/cd-rom.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgin-3POpRRjcr1HJpDN-c2KPJkCRQNfmOBPs_qIt4RAWpVajJtuWNC1EF3c1G81zEhAMoxP1X9clkfUD05dQojZLuwHGMnQR_uZhKaJk02fVMX_TxXEbgaWGNVDmH-2_wz9h-S1nXNVMoF/s320/cd-rom.gif" alt="" id="BLOGGER_PHOTO_ID_5210969137580022786" border="0" /></a> </div> <center style="font-family: trebuchet ms;"> <p><br /></p></center> <blockquote style="font-family: trebuchet ms;"> <p><span style="color:#000000;"><span style="font-size:+1;"><b>Removable Hard Disk</b></span></span> </p> <p><span style="color:#000000;"><span style="font-size:+1;">A zip disk is a removable disk that holds a large amount of information. A zip disk can be used to achieve, protect and transfer large amounts of data.</span></span><br /></p></blockquote> <center style="font-family: trebuchet ms;"> <p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQQWtE3uEis70AOe6bb4c9CRlKzzoJ9sYzewq0HNrXzPJwXuUqne7FDCKStXheweAtUbyxAgpDou-LA1jc4zxzhGdK0JPZwkEoN80wr8c44nJJGnJToj4f4wCja6qWed1M5UQ9u9qCH6jl/s1600-h/zipdrive.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQQWtE3uEis70AOe6bb4c9CRlKzzoJ9sYzewq0HNrXzPJwXuUqne7FDCKStXheweAtUbyxAgpDou-LA1jc4zxzhGdK0JPZwkEoN80wr8c44nJJGnJToj4f4wCja6qWed1M5UQ9u9qCH6jl/s320/zipdrive.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210969078087797874" border="0" /></a><br /><span style="color:#000000;"><span style="font-size:+1;">Zip Drive & Zip Disk</span></span><br /></p></center><!-- #EndEditable --> <center style="font-family: trebuchet ms;"> <p> </p></center>qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0tag:blogger.com,1999:blog-6926266186147655709.post-5437019045635546422008-06-12T05:07:00.000-07:002008-07-01T04:16:32.354-07:00System Unit<span style="font-family: trebuchet ms;font-size:+1;" >A computer system unit contains many parts. </span> <a style="font-family: trebuchet ms;" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjz-84EMPW55_tICTWQecKyHlm9RlScS2lsvFpcrrIQeeppEgbtqAnxEkc6y3JQdAuvTZQkVqeTC7Y3M0G_ittPxvB3CVkRhPM59qm3fvrXm5krFrENSts62XNVdSaJJKl369BqnIdlQn8T/s1600-h/insideapc.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 382px; height: 250px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjz-84EMPW55_tICTWQecKyHlm9RlScS2lsvFpcrrIQeeppEgbtqAnxEkc6y3JQdAuvTZQkVqeTC7Y3M0G_ittPxvB3CVkRhPM59qm3fvrXm5krFrENSts62XNVdSaJJKl369BqnIdlQn8T/s320/insideapc.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210965782592710466" border="0" /></a> <p style="font-family: trebuchet ms;"><span style="font-size:+1;"><b>Motherboard</b> - <span style="font-size:100%;">The motherboard is the main circuit board of a microcomputer. It is also known as the mainboard or system board.</span></span> </p><p style="font-family: trebuchet ms;"><span style="font-size:+1;"><b>CPU</b> - <span style="font-size:100%;">The CPU is the central electronic chip that determines the processing power of the computer.</span></span> </p><p style="font-family: trebuchet ms;"><span style="font-size:+1;"><b>Memory</b> - <span style="font-size:100%;">Memory is the part of the computer that temporarily stores applications, documents, and stem operating information.</span></span> </p><p style="font-family: trebuchet ms;"><span style="font-size:+1;"><b>Bus</b> - <span style="font-size:100%;">A bus is an electronic line that allows 1s and 0s to move from one place to another.</span></span> </p><p style="font-family: trebuchet ms;"><span style="font-size:+1;"><b>Expansion Slots</b> - <span style="font-size:100%;">Expansions slots appear on the motherboard. They are sockets into which adapters are connected.</span></span> </p><p style="font-family: trebuchet ms;"><span style="font-size:+1;"><b>Ports and Connectors</b> - <span style="font-size:100%;">A port is a connector located on the motherboard or on a separate adapter.</span></span> </p><p style="font-family: trebuchet ms;"><span style="font-size:+1;"><b>Bays</b> - <span style="font-size:100%;">A bay is a space inside the computer case where a hard drive, floppy drive or CD-ROM drive sits</span></span> </p><p style="font-family: trebuchet ms;"><span style="font-size:+1;"><b>Power Supply</b> - <span style="font-size:100%;">A power supply changes normal household electricity into electricity that a computer can use.</span></span> </p><p style="font-family: trebuchet ms;"><span style="font-size:+1;"><b>Sound Components</b> - <span style="font-size:100%;">A sound card lets a computer play and record high quality sound.</span></span><br /><br /><br /><b><span style="color:#000000;"><span style="font-size:+2;"><span style="font-size:130%;">Central Processing Unit (CPU)</span><br /><br /></span></span></b><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJ4FoEvuIgc8g9ZcHYtnW4npTiBPBaKxyYVf3SnYvokP-w8S2b0Ai9hoYSbuiRYfRjNa5l-0F7P0xoZXeMfXczwX__rwncR-mOg_LOU56NI1R1VLXm6gcB8cDiykTMtVuAev3qBwcHK2DD/s1600-h/cpu.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJ4FoEvuIgc8g9ZcHYtnW4npTiBPBaKxyYVf3SnYvokP-w8S2b0Ai9hoYSbuiRYfRjNa5l-0F7P0xoZXeMfXczwX__rwncR-mOg_LOU56NI1R1VLXm6gcB8cDiykTMtVuAev3qBwcHK2DD/s320/cpu.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210966247139897618" border="0" /></a><b><span style="color:#000000;"><span style="font-size:+2;"><br /><br /></span></span></b> </p><blockquote style="font-family: trebuchet ms;"> <h3><span style="color:#000000;"><span style="font-size:+1;">Does all of the work for the computer</span></span></h3></blockquote> <ul style="font-family: trebuchet ms;"><ol><li><span style="font-size:100%;color:#000000;">Does all of the mathematics, mainly addition</span> </li><li><span style="font-size:100%;color:#000000;">Does all the logical comparisons of values</span> </li><li><span style="font-size:100%;color:#000000;">Directs the flow of data in a computer</span> </li><li><span style="color:#000000;"><span style="font-size:+1;"><span style="font-size:100%;">Controls the operation of the parts of the computer</span><br /><br /></span></span></li></ol><h3><span style="color:#000000;"><span style="font-size:+1;">Today, all CPUs are microprocessors</span></span></h3><ol><li><span style="font-size:100%;color:#000000;">A microprocessor is a complete computer on a silicon chip </span> </li><li><span style="font-size:100%;color:#000000;">A microprocessor does all of the functions of a computer</span> <ul><li><span style="font-size:100%;color:#000000;">stores data and instructions waiting to be used</span> </li><li><span style="font-size:100%;color:#000000;">follows changeable instructions</span> </li><li><span style="color:#000000;"><span style="font-size:+1;"><span style="font-size:100%;">does input, processing, and output</span><br /><br /></span></span></li></ul></li></ol><h3><span style="color:#000000;"><span style="font-size:+1;">CPUs have three basic parts</span></span></h3><ol><li><span style="color:#000000;"><span style="font-size:+1;">The Arithmetic Logic Unit (ALU)</span></span> <ul><li><span style="font-size:100%;color:#000000;">does all of the mathematics in a computer</span> </li><li><span style="font-size:100%;color:#000000;">does all of the logic comparisons of values</span> </li><li><span style="font-size:100%;color:#000000;">some common logic comparison symbols</span> <ul><li><span style="font-size:100%;color:#000000;">= equal to</span> </li><li><span style="font-size:100%;color:#000000;"><> </li><li><span style="font-size:100%;color:#000000;">> greater than</span> </li><li><span style="font-size:100%;color:#000000;"><= less than or equal to</span> </li><li><span style="font-size:100%;color:#000000;">>= greater than or equal to</span> </li><li><span style="color:#000000;"><span style="font-size:+1;"><span style="font-size:100%;"><> not equal</span><br /><br /></span></span></li></ul></li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">The Control Unit</span></span> <ul><li><span style="font-size:100%;color:#000000;">directs the flow of information into the CPU and/or memory or storage</span> </li><li><span style="color:#000000;"><span style="font-size:+1;"><span style="font-size:100%;">controls which instructions the CPU will do next<br /></span><br /></span></span></li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;">Registers</span></span> <ul><li><span style="font-size:100%;color:#000000;">Used to store data and instructions inside the processor</span> </li><li><span style="color:#000000;"><span style="font-size:+1;"><span style="font-size:100%;">Size of the registers can affect the speed and performance of the processor<br /></span><br /></span></span></li></ul></li></ol><h3><span style="color:#000000;"><span style="font-size:+1;">Speed of CPUs</span></span></h3><ol><li><span style="font-size:100%;color:#000000;">The speed of CPUs is measured in hertzs.</span> <ul><li><span style="font-size:100%;color:#000000;">A hertz is on cycle per second.</span> </li><li><span style="font-size:100%;color:#000000;">Need to measure time to determine cycles per second</span> <ul><li><span style="font-size:100%;color:#000000;">All computers have a clock built into them for timing the cycles</span> </li><li><span style="font-size:100%;color:#000000;">The clock is usually located in a small metal box on the motherboard.</span> </li></ul> </li><li><span style="font-size:100%;color:#000000;">Today, many CPUs can complete over six (6) instructions per second.<br /><br /></span></li></ul> </li><li><span style="font-size:100%;color:#000000;">Speeds of modern CPUs</span> <ul><li><span style="font-size:100%;color:#000000;">Most computers have a CPU that can do more than 400 MHz.</span> <ul><li><span style="font-size:100%;color:#000000;">MHz stands for megahertzs</span> </li><li><span style="font-size:100%;color:#000000;">A MHz is 1,000,000 cycles per second.</span> </li></ul> </li><li><span style="color:#000000;"><span style="font-size:+1;"><span style="font-size:100%;">Computers will soon be at speeds of over a gigahertz, 1,000,000,000 Hertzs.</span><br /></span></span></li></ul></li></ol></ul> <p style="font-family: trebuchet ms;"><span style="font-size:130%;"><b><span style="color:#000000;">Memory</span></b></span></p> <h3 style="font-family: trebuchet ms;"><span style="font-size:100%;color:#000000;">Primary memory can be used directly by the CPU</span></h3> <ol style="font-family: trebuchet ms;"><li><span style="font-size:100%;color:#000000;">Consists of silicon chips, usually either VLS or VLSI technology is used to create the chips</span> </li><li><span style="font-size:100%;color:#000000;">Two forms of Primary Memory</span> <ul><li><span style="font-size:100%;color:#000000;">Read Only Memory (ROM)</span> </li><li><span style="font-size:100%;color:#000000;">Random Access Memory (RAM)</span> </li></ul> </li><li><span style="font-size:100%;color:#000000;">Primary memory is also called primary storage</span> </li></ol> <h3 style="font-family: trebuchet ms;"><span style="color:#000000;"><span style="font-size:+1;"><span style="font-size:130%;">Read Only Memory (ROM)<br /></span><br /></span></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgliG9uDfqd8Y9gNJQrf2YahjpjmiQSIiiHxC2qitbr7ksjyYrmWPzCTvJDlKHVITg3mTGliZVXzuonEl_Whj9zP2TIftu7nNYBtlZ8_qQoqrCPZ5JbFxbs3AyCNgYOkqiI3UxfJontqKKK/s1600-h/rom.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgliG9uDfqd8Y9gNJQrf2YahjpjmiQSIiiHxC2qitbr7ksjyYrmWPzCTvJDlKHVITg3mTGliZVXzuonEl_Whj9zP2TIftu7nNYBtlZ8_qQoqrCPZ5JbFxbs3AyCNgYOkqiI3UxfJontqKKK/s320/rom.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210966385535949458" border="0" /></a><br /></h3> <ol style="font-family: trebuchet ms;"><li><span style="font-size:130%;color:#000000;">Stores instructions that are used by the CPU</span> <ul style="font-style: italic;"><li><span style="font-size:100%;color:#000000;">Tells the CPU how to be the kind of computer it is, for example a Windows, Macintosh, or Play Station computers.</span> </li><li><span style="font-size:100%;color:#000000;">Tells the CPU how to work with the different parts of the computer</span> </li><li><span style="font-size:100%;color:#000000;">ROM can also hold programs that are directly accessed by the CPU. One such program is the self-test when the computer is first turned on. The self-test tests to seem if all the parts on the main circuit board (mother board) are working correctly.</span> </li></ul> </li><li><span style="font-size:130%;color:#000000;">The instructions in ROM can not usually be changed</span> <ul><li><span style="font-size:100%;color:#000000;">T<span style="font-style: italic;">he instructions are built into the electronic circuits of the chips</span></span> </li><li style="font-style: italic;"><span style="font-size:100%;color:#000000;">These instructions in ROM are called <b>firmware</b></span> </li><li style="font-style: italic;"><span style="font-size:100%;color:#000000;">To change the instructions in ROM you need to usually change the chips or do some other special process that is normally not available to an average user.</span> </li></ul> </li><li><span style="font-size:100%;color:#000000;"><span style="font-size:130%;">The instructions in ROM are nonvolatile.</span> They stay in ROM even when the computer is turned off.</span> </li><li><span style="font-size:130%;color:#000000;">Access to information is random access.</span> <ul><li><span style="font-size:100%;color:#000000;">Random access means that any piece of information in ROM can be accessed at any given time without access other information first. It is a lot like the tracks on a music CD. You can access any track at any time and in any order.</span> </li><li><span style="font-size:100%;color:#000000;">The other kind of access is sequential access. You must access the information in the order that they are located. This is a lot like a music tape. You must play the songs in order, or you have to fast forward past songs to get to the one you want.</span> </li></ul></li></ol> <h3 style="font-family: trebuchet ms;"><span style="color:#000000;"><span style="font-size:+1;">R<span style="font-size:130%;">andom Access Memory (RAM)</span><br /><br /></span></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQHB0-T3lwhhy4fNU-tVRj7jnCjbnTvi38jkb-kM8aicEtD_ZVckS0YON1_zVuAJEjKKAdi5PhNEGQukxFZG40La-tmEXD2n0duSpfPQ_BdfXzlx9nqustiPRaZV1DmID8Y9ektHtlAWHK/s1600-h/ram.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQHB0-T3lwhhy4fNU-tVRj7jnCjbnTvi38jkb-kM8aicEtD_ZVckS0YON1_zVuAJEjKKAdi5PhNEGQukxFZG40La-tmEXD2n0duSpfPQ_BdfXzlx9nqustiPRaZV1DmID8Y9ektHtlAWHK/s320/ram.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210966327223507138" border="0" /></a><br /></h3> <ol style="font-family: trebuchet ms;"><li><span style="font-size:130%;color:#000000;">Store data and instructions that are used by the CPU to perform some task.</span> <ul><li><span style="font-size:100%;color:#000000;">These instructions are usually loaded into RAM from a secondary storage device.</span> </li><li><span style="font-size:100%;color:#000000;">RAM is also used to store instructions that tell the CPU how to work with its parts. These instructions are usually called drivers.</span> </li></ul> </li><li><span style="font-size:130%;color:#000000;">The instructions in RAM are constantly changing, depending on the needs of the CPU.</span> </li><li><span style="font-size:130%;color:#000000;">The instructions in RAM are volatile.</span> <ul><li><span style="font-size:100%;color:#000000;">When the computer is turned off the information in RAM disappears.</span> </li><li><span style="font-size:100%;color:#000000;">The information in RAM needs to be saved to secondary storage before the computer is turned off.</span> </li></ul> </li><li><span style="font-size:130%;color:#000000;">Access to information is random access.</span> </li></ol><!-- #EndEditable -->qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0tag:blogger.com,1999:blog-6926266186147655709.post-24437778624273732612008-06-12T04:49:00.000-07:002008-07-01T04:16:48.264-07:00Output Devices<span style="font-family: trebuchet ms;font-size:100%;" ><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:130%;" >Output Devices</span><br /><br />An output device displays information on a screen, creates printed copies or generates sound. A monitor, printer, and speakers are examples of output devices.<br /></span><h3 style="color: rgb(0, 102, 0); font-family: trebuchet ms; font-weight: bold;font-family:trebuchet ms;" ><span style="color: rgb(0, 0, 0);font-size:100%;" >Some Common Output Devices:</span></h3> <h3 style="font-family: trebuchet ms;font-family:trebuchet ms;" ><span style="font-size:100%;"><b><span style="color: rgb(0, 0, 0);">Monitors and Displays</span></b></span></h3> <ul style="font-family: trebuchet ms;font-family:trebuchet ms;" ><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Shows the processed information on a screen</span> <ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" >A monitor uses a Picture Tube like a television with the image displayed on the front of the tube, which is called the screen.<br /><br /></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjk7C8IVgiprs_cIVRfOzeHYZG_karW6KnPJE5PdefAlG-8Uwe7MbgQsU-SBANSUWcrmFc-sj5PB9zpzbua4UeybFEKRZP_MSNfYgKF84NPOff5sEL6swLvqlDFHf6wWposeKfkLEkZGBQO/s1600-h/monitorscrt.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjk7C8IVgiprs_cIVRfOzeHYZG_karW6KnPJE5PdefAlG-8Uwe7MbgQsU-SBANSUWcrmFc-sj5PB9zpzbua4UeybFEKRZP_MSNfYgKF84NPOff5sEL6swLvqlDFHf6wWposeKfkLEkZGBQO/s320/monitorscrt.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210964324981801090" border="0" /></a><br /><span style="color: rgb(0, 0, 0);font-size:100%;" ><br /></span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Displays are flat and use plasma, LCD, active-matrix, or some other technology.<br /><br /></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmeibOdF3JwBoWZxlAQrMQCwz-Dd8oWFlCLpoaSrtSKuQo-pme0uYTmbDJW9rSS6m6DEiFTPAiuFbFeMAg06mqvxPsEqKN2PMbZdWKcr8SALUyH9VePSBJRaB4w7Ojvaw0MB1cKCvLjULr/s1600-h/LCD.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmeibOdF3JwBoWZxlAQrMQCwz-Dd8oWFlCLpoaSrtSKuQo-pme0uYTmbDJW9rSS6m6DEiFTPAiuFbFeMAg06mqvxPsEqKN2PMbZdWKcr8SALUyH9VePSBJRaB4w7Ojvaw0MB1cKCvLjULr/s320/LCD.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210963990309263506" border="0" /></a><br /></li></ul> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Monitors used to be called Cathode Ray Tubes (CRTs) because of the picture tube, which is a large vacuum tube. </span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >A monitor or display produce a soft copy. When the device is turned off the information goes away.</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Monitors are slowly being replaced by flat panel displays.<br /></span> <center></center></li></ul> <p style="font-family: trebuchet ms;font-family:trebuchet ms;" ><span style="font-size:100%;"><b><span style="color: rgb(0, 0, 0);">Printers</span></b></span></p> <ul style="font-family: trebuchet ms;font-family:trebuchet ms;" ><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Printers produce a hard copy</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >The information is printed on paper and can be used when the device is off.</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >It is also called a printout</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Dot-matrix printers (impact printer)<br /><br /></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7gpMGiUlPezgZ006T4QbGD67hlXRExnFDqT5-nd3Is7neaF-urayVOl9hyphenhyphenkab9-_odpsRuKXnU52QcDwM9rkBSPukdYkZpGT7ig0DXZdhll2Ow_Bdw0w4hoEnYLp2Lh9Gf0avaajYiYsJ/s1600-h/printersdotmatrix.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7gpMGiUlPezgZ006T4QbGD67hlXRExnFDqT5-nd3Is7neaF-urayVOl9hyphenhyphenkab9-_odpsRuKXnU52QcDwM9rkBSPukdYkZpGT7ig0DXZdhll2Ow_Bdw0w4hoEnYLp2Lh9Gf0avaajYiYsJ/s320/printersdotmatrix.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210964387374674114" border="0" /></a><br /><span style="color: rgb(0, 0, 0);font-size:100%;" ><br /></span> <ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Uses metal pins to strike an inked ribbon to make dots on a piece of paper.</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Can see the dots that make up the letters or images.</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Lowest print quality of all of the printers.</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Very low in cost per page to use.</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Rarely used today because of the poor print quality, but still used in business to print multi-part forms.<br /><br /></span></li></ul> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Ink jet printers (non-impact printer)<br /><br /></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZgMWEiOc8cmhRHn-yuVZs9YbkBZ6EyahePPSXiWBXy_PdMBC-ckiu8TY5q6fVkUf66iT4ONMtZM22081GK8vC5w7v6ve0cLfulXbYFXicIoI-B_FkyNMqlLFiaEqe2fOgO052eM-6NNqk/s1600-h/inkjet.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZgMWEiOc8cmhRHn-yuVZs9YbkBZ6EyahePPSXiWBXy_PdMBC-ckiu8TY5q6fVkUf66iT4ONMtZM22081GK8vC5w7v6ve0cLfulXbYFXicIoI-B_FkyNMqlLFiaEqe2fOgO052eM-6NNqk/s320/inkjet.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210963210752587634" border="0" /></a><br /><span style="color: rgb(0, 0, 0);font-size:100%;" ><br /></span> <ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Use drops of magnetic ink to produce dots on a page to produce text or images.</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >The print quality is almost the same as a laser printer's.</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Problems with the ink</span> <ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" >The ink is very expensive</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >The ink is water soluble and will run if the paper gets wet</span> </li></ul> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Highest cost per page of all the printers</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >For producing color documents, it has the highest quality at a reasonable price.<br /><br /></span></li></ul> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Laser printers (non-impact printer)<br /><br /></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjRG3dSf66MnQM8JJMBNZd57peMWeb8ArMIu_pXlqO276sliTrrE0FA4h0aaQ6AGPqKfoJ2Ew6EnuVJE3VK3JgFTkPZKn23ezt-nNXBSV_cz5w7bovgc-6D1_0U0tezmX6P5DLOrIMSWXWg/s1600-h/laserprinters.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjRG3dSf66MnQM8JJMBNZd57peMWeb8ArMIu_pXlqO276sliTrrE0FA4h0aaQ6AGPqKfoJ2Ew6EnuVJE3VK3JgFTkPZKn23ezt-nNXBSV_cz5w7bovgc-6D1_0U0tezmX6P5DLOrIMSWXWg/s320/laserprinters.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210963930654372146" border="0" /></a><br /><span style="color: rgb(0, 0, 0);font-size:100%;" ><br /></span> <ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" >How the laser printer produces an image</span> <ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" >A laser or LEDs make dots on a light sensitive drum</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Toner (very tiny particles of plastic) stick to the drum where the dots where made</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Paper is pressed against the drum and the toner is placed on the paper</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >The paper is heated and the toner melts into the paper</span> </li></ul> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Produces the highest quality printout</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >For black and white printouts, very low cost per page</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Printout is permanent</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Color laser printers are still fairly expensive ($3,000 to $10,000)</span> </li></ul></li></ul> <p style="font-family: trebuchet ms; color: rgb(0, 102, 0);font-family:trebuchet ms;" ><span style="font-size:100%;"><b><span style="color: rgb(0, 0, 0);">Speakers</span></b></span></p> <ul style="font-family:trebuchet ms;"><li> <p><span style="color: rgb(0, 0, 0); font-family: trebuchet ms;font-size:100%;" >used to output sound<br /><br /></span><a style="font-family: trebuchet ms;" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEieTMZmkDT5UVAeuNVXUL4nE5chI0oq_lIBfmRAUbtxnQuSA9djhIAUGATUEZRjU-FrRmNEMPzjGeAJDJxQNfjQsiS5QBmpOAxMz2_BNm-cuDErJ-NwhoJPAT83UvJDCqjxp7Es_gDh1DI_/s1600-h/speakers.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEieTMZmkDT5UVAeuNVXUL4nE5chI0oq_lIBfmRAUbtxnQuSA9djhIAUGATUEZRjU-FrRmNEMPzjGeAJDJxQNfjQsiS5QBmpOAxMz2_BNm-cuDErJ-NwhoJPAT83UvJDCqjxp7Es_gDh1DI_/s320/speakers.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210964533208163138" border="0" /></a><br /></p></li></ul><!-- #EndEditable -->qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0tag:blogger.com,1999:blog-6926266186147655709.post-74886751807605392772008-06-12T04:31:00.000-07:002008-07-01T04:17:02.257-07:00Input Devices<span style=";font-family:trebuchet ms;font-size:100%;" ><span style="color: rgb(0, 102, 0); font-weight: bold;font-size:130%;" >Input Devices</span><br /><br />An input device lets you communicate with a computer. You can use input devices to enter information and issue commands. A keyboard, mouse, scanner, digital camera, touch pads and joystick are examples of input devices.</span><p style="font-family: trebuchet ms;"> </p><h3 style="color: rgb(0, 102, 0);font-family:trebuchet ms;"><span style="font-size:130%;">Some Common Computer Input Devices:</span></h3> <p style="font-family: trebuchet ms;"> </p><center style="font-family: trebuchet ms;"> <center> <p> </p><center> <p align="left"><span style="font-size:100%;"><b><span style="color: rgb(0, 0, 0);"> </span></b><span style="color: rgb(0, 102, 0);font-size:100%;" ><b>Keyboard </b></span></span><span style="color: rgb(0, 0, 0);font-size:100%;" ><br /></span> </p><ul><li> <div align="left"><span style="color: rgb(0, 0, 0);font-size:100%;" >Used to type data into the computer</span></div> </li><li> <div align="left"><span style="color: rgb(0, 0, 0);font-size:100%;" >Most common input device today</span></div> </li><li> <div align="left"><span style="color: rgb(0, 0, 0);font-size:100%;" >Has special keys for giving the computer commands</span></div> <div align="left"> <ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Commands tell the computer to do something, like save the file</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >These special keys are called command or function keys</span></li></ul><span style="font-size:100%;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrXspkTh69iTAI1pH4huDuJrXNW-SDjiNMhs14KV3ka-S-kif90JEo2ePyK-1bTZ3VFSOUEcsXDnILeVs8ybGqXgjaBLWYUMHJHFiWv2BdTxwrDpCATiiwG6Ur0KwToA5U6f7mGNVgYgdi/s1600-h/keyboard.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 224px; height: 85px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrXspkTh69iTAI1pH4huDuJrXNW-SDjiNMhs14KV3ka-S-kif90JEo2ePyK-1bTZ3VFSOUEcsXDnILeVs8ybGqXgjaBLWYUMHJHFiWv2BdTxwrDpCATiiwG6Ur0KwToA5U6f7mGNVgYgdi/s320/keyboard.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210957002854995762" border="0" /></a></span></div></li></ul><div style="text-align: left;"> <p align="left"><span style="color: rgb(0, 0, 0);font-size:100%;" ><b><span style="color: rgb(0, 102, 0);">Pointing Devices</span> </b></span> </p><ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Pointing devices move some object on the screen and can do some action</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Common pointing devices</span> <ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" ><span style="color: rgb(0, 102, 0); font-weight: bold;">Mouse</span> - most common pointing device </span> </li></ul> <p align="left"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYLp9WFEMgkPKXxfuvfVa8HivY0g5Whkj9TrCtL2Pgz2BkPNcKiyWLJc_GmvFRc1OaWOGKoVya2mMb5dkQs4lZsMookIdKnxzs10jK8RjgnyULW-H6kTmqcQvxFnLMOYh0rj3aWyn09gSX/s1600-h/mouse.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 119px; height: 97px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYLp9WFEMgkPKXxfuvfVa8HivY0g5Whkj9TrCtL2Pgz2BkPNcKiyWLJc_GmvFRc1OaWOGKoVya2mMb5dkQs4lZsMookIdKnxzs10jK8RjgnyULW-H6kTmqcQvxFnLMOYh0rj3aWyn09gSX/s320/mouse.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210957512158331698" border="0" /></a><span style="font-size:100%;"><br /></span></p> <ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" ><span style="font-weight: bold; color: rgb(0, 102, 0);">Track ball</span> - basically an upside down mouse<br /><br /></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2OY0baTSNOXh_5PnUp0oX45CSKT9xMJXislWnS08IyF_JJGoDAc05LriHAm4bfTKglaarMQqOy105PpJ2vT-mD0dkKZ1DvEix6pQt9d9TpG1zTYlDltjH-GOJ0BsLtKs8iMkp8hZvdjzs/s1600-h/tball.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 146px; height: 113px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2OY0baTSNOXh_5PnUp0oX45CSKT9xMJXislWnS08IyF_JJGoDAc05LriHAm4bfTKglaarMQqOy105PpJ2vT-mD0dkKZ1DvEix6pQt9d9TpG1zTYlDltjH-GOJ0BsLtKs8iMkp8hZvdjzs/s320/tball.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210957569940226850" border="0" /></a></li><li><span style="color: rgb(0, 0, 0);font-size:100%;" ><span style="color: rgb(0, 102, 0); font-weight: bold;">Joystick</span><br /><br /></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilf8rfzlvqIVX8l5EkmnmO77sG6qN2eRhqTM5cgFu1IR9MEwrcUH531dB2nzQWok173ZuvjrBjKJV-LqmhQvqs_EdAkEJvwh9ymXsL0kLSaiVjTLG3l2tYoSohDh6TvWx_srUfXL0xqxIN/s1600-h/joystick.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 115px; height: 128px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilf8rfzlvqIVX8l5EkmnmO77sG6qN2eRhqTM5cgFu1IR9MEwrcUH531dB2nzQWok173ZuvjrBjKJV-LqmhQvqs_EdAkEJvwh9ymXsL0kLSaiVjTLG3l2tYoSohDh6TvWx_srUfXL0xqxIN/s320/joystick.gif" alt="" id="BLOGGER_PHOTO_ID_5210958128603268146" border="0" /></a><br /><span style="color: rgb(0, 0, 0);font-size:100%;" ><br /></span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" ><span style="font-weight: bold; color: rgb(0, 102, 0);">Game controller</span><br /><br /></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgM_mCrk8j2YF6iX-assUKflHf7L5TmlzBQbNRq43j0qOj1PatfGFS_a4uCgw8lpuMELdYGyBVxuLC9SE8FXhlN4w7xLiJcDY41pbQQ-PsDKc4-8cHjH9WlwTJrICRkOy5lzA9hxRF3Q9nB/s1600-h/controller.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 130px; height: 110px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgM_mCrk8j2YF6iX-assUKflHf7L5TmlzBQbNRq43j0qOj1PatfGFS_a4uCgw8lpuMELdYGyBVxuLC9SE8FXhlN4w7xLiJcDY41pbQQ-PsDKc4-8cHjH9WlwTJrICRkOy5lzA9hxRF3Q9nB/s320/controller.gif" alt="" id="BLOGGER_PHOTO_ID_5210958286541563522" border="0" /></a><span style="font-size:100%;"><br /></span></li></ul></li></ul> <p> </p><center> <center></center> <center> <p> </p><center> <center></center> <p style="color: rgb(0, 102, 0);" align="left"><span style="font-size:130%;">Scanner</span> </p></center></center></center> <p><span style="color: rgb(0, 0, 0);font-size:100%;" >A scanner allows you to scan documents, pictures, or graphics and view them on the computer. You can also use software to edit the items you scan.</span> </p><ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Used to put printed pictures and text into a computer</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Converts an image into dots that the computer can understand</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >To scan text, optical character recognition (OCR) software is needed</span> </li></ul> <p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7EeQiURyWAgCjiR6_OWMHM1cAo27rWjfVwRPESAaLcgARGFD6QYn5lwtkmiQndPPOkpJvamswpNp5J8hLWxoBsxExcBU4rr7dfW3oQeVj-0eBcC1X0kUmQjXOUoI-BOX94bPAQAnzoezQ/s1600-h/scanner.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 166px; height: 145px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7EeQiURyWAgCjiR6_OWMHM1cAo27rWjfVwRPESAaLcgARGFD6QYn5lwtkmiQndPPOkpJvamswpNp5J8hLWxoBsxExcBU4rr7dfW3oQeVj-0eBcC1X0kUmQjXOUoI-BOX94bPAQAnzoezQ/s320/scanner.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210958437844954306" border="0" /></a><br /><span style="font-size:100%;"><br /><br /></span> </p><center style="color: rgb(0, 102, 0);"> <center> <center> <p align="left"><span style="font-size:100%;"><span style="font-size:130%;">Digital Camera</span> </span></p></center></center></center> <ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Used to take electronic pictures of an object</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >The pictures taken by a digital camera can be used directly by a computer</span> </li></ul> <p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiA8QnzUBotdAD-2hRCX39gnEn0H5WhQnOtm_f8HAM5jficMbehgkczcreMlMbB1Y4cLt7gXGkln720AvhG8thnfujuBVIfqv8W9lg-eX-W5Y-y9BVqleRImI42tCxar6PNoXgT_3BUXqEY/s1600-h/digitcam.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 180px; height: 151px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiA8QnzUBotdAD-2hRCX39gnEn0H5WhQnOtm_f8HAM5jficMbehgkczcreMlMbB1Y4cLt7gXGkln720AvhG8thnfujuBVIfqv8W9lg-eX-W5Y-y9BVqleRImI42tCxar6PNoXgT_3BUXqEY/s320/digitcam.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210958671299336482" border="0" /></a><span style="font-size:100%;"><br /><br /></span> </p><center style="color: rgb(0, 102, 0);"> <center> <center> <p align="left"><span style="font-size:100%;"><b>Microphone</b></span> </p></center></center></center> <ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Used to put sound into a computer</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Need sound recording software</span> </li></ul> <p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiViZx50RiBgqdAPCqm8yAjmNYmPQa0uILpe_k2AomHUEAXh0pHiPo2GYse3V1cAz9sGf2JxUtnBCBR_vBYE6cfT-z348AU4fEYrfxWEVcUGwWUwLJLoaOSby7zZw4AAp_ncswfQf0ef_2I/s1600-h/microphone.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 113px; height: 108px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiViZx50RiBgqdAPCqm8yAjmNYmPQa0uILpe_k2AomHUEAXh0pHiPo2GYse3V1cAz9sGf2JxUtnBCBR_vBYE6cfT-z348AU4fEYrfxWEVcUGwWUwLJLoaOSby7zZw4AAp_ncswfQf0ef_2I/s320/microphone.gif" alt="" id="BLOGGER_PHOTO_ID_5210958885202384434" border="0" /></a> </p><center style="color: rgb(0, 102, 0);"> <center> <center> <p align="left"><span style="font-size:100%;"><b>CD-ROM/DVD-ROM</b></span> </p></center></center></center> <ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Can be used to put both sound and images into a computer</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Use a laser to read a Compact Disk (CD) or a DVD disk<br /><br /></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9zEdVFT3HOsm56RFADv5af9GU71EVS09KA8-VUgw4qDv7maeeYmJRsLrbpthGvkfbLVsz0jm5wa5EeGofDgWdFLRg-0fEUFY_xOImZ64_MgN3fbZQ_ZEGQ5NApCUmgj7S3mBUFpR5-w-T/s1600-h/cd-rom.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9zEdVFT3HOsm56RFADv5af9GU71EVS09KA8-VUgw4qDv7maeeYmJRsLrbpthGvkfbLVsz0jm5wa5EeGofDgWdFLRg-0fEUFY_xOImZ64_MgN3fbZQ_ZEGQ5NApCUmgj7S3mBUFpR5-w-T/s320/cd-rom.gif" alt="" id="BLOGGER_PHOTO_ID_5210959246726794578" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-IH5PD7YN5SnBjz7KQQxsgQNHbTLArJaQgjpRf6FntugCEZcDh4F98O5OHUeqc0lcdDpPIqasJD6N0D2rxEeVOxAhWX5P7lNg0G_tlVVkAdS9w0hjhx7mtZ7c0OxJSuBhZ_7NjWtqlfp_/s1600-h/cdrom.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 125px; height: 119px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-IH5PD7YN5SnBjz7KQQxsgQNHbTLArJaQgjpRf6FntugCEZcDh4F98O5OHUeqc0lcdDpPIqasJD6N0D2rxEeVOxAhWX5P7lNg0G_tlVVkAdS9w0hjhx7mtZ7c0OxJSuBhZ_7NjWtqlfp_/s320/cdrom.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210959045845829090" border="0" /></a><span style="color: rgb(0, 0, 0);font-size:100%;" ><br /></span></li></ul> <p> </p><p> </p><center style="color: rgb(0, 102, 0);"> <center> <center> <p align="left"><span style="font-size:130%;">Video Capture Card</span> </p></center></center></center> <ul><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Usually place inside the computer's case</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Use to put video into a computer</span> </li><li><span style="color: rgb(0, 0, 0);font-size:100%;" >Need a video source, either a video camera or video recorder</span> </li></ul><!-- #EndEditable --></div></center></center></center>qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com1tag:blogger.com,1999:blog-6926266186147655709.post-16766808081244104402008-06-12T04:30:00.001-07:002008-07-01T04:17:15.262-07:00Categories of Computers<font style="" face="trebuchet ms" size="3"><font size="4">Categories of Computers</font><br /></font> <p face="trebuchet ms" style="text-align: justify;"><font style="color: rgb(0, 0, 0);" size="3">Personal computers</font> </p><p face="trebuchet ms" style="text-align: justify;"><font style="color: rgb(0, 0, 0);" size="3"><a name="Personal"></a>Personal computers are desktop computers designed for an individual's use. They run programs designed to help individuals accomplish their work more productively.</font><font size="3"><br /></font></p><div style="text-align: justify; font-family: arial;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvLe6vTzrvAU9qk5UlhpRsuOqJCkjxgvgFJ6hGN7D3tgFBxY3KhSZN1lmeVD5ReuYMsjez2f8Qsp2TkpROVIiiHR_FkVTnKIREPOVld8CO2fADpr5SLQ71BL1wiC3IM1JRa12qIqz7A0vz/s1600-h/computer.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvLe6vTzrvAU9qk5UlhpRsuOqJCkjxgvgFJ6hGN7D3tgFBxY3KhSZN1lmeVD5ReuYMsjez2f8Qsp2TkpROVIiiHR_FkVTnKIREPOVld8CO2fADpr5SLQ71BL1wiC3IM1JRa12qIqz7A0vz/s320/computer.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210951556937186802" border="0"></a><p style="text-align: center;"><br /></p><p> </p><p face="trebuchet ms"><font style="color: rgb(0, 0, 0);"><font size="1">Servers</font></font> </p><p face="trebuchet ms"><a name="Servers"></a><font style="color: rgb(0, 0, 0);" size="3">Servers are not designed to be used directly. They make programs and data available for people hooked up to a computer network, a collection of computers connected together so that they can exchange data.</font></p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisOz6Ttpmfvg7xOc3oVLnDCm9xlEV542HBAI0bgiozI5f6yMZ2iq2i5YIn4mO0DhnwzSFmxrtxQOH8xCqaVcZGgfV-h5PUyGvY8QKQMS4Xf_oxU4htX3s66q0K3E5v55IJPLHWbS8ukHJa/s1600-h/server.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisOz6Ttpmfvg7xOc3oVLnDCm9xlEV542HBAI0bgiozI5f6yMZ2iq2i5YIn4mO0DhnwzSFmxrtxQOH8xCqaVcZGgfV-h5PUyGvY8QKQMS4Xf_oxU4htX3s66q0K3E5v55IJPLHWbS8ukHJa/s320/server.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210951971910014418" border="0"></a><br /><p style="text-align: left;"> </p><p face="trebuchet ms"><font style="color: rgb(0, 0, 0);" size="4">Minicomputers</font> </p><p><a name="Minicomputers"></a><font style="color: rgb(0, 0, 0);" face="trebuchet ms" size="3">Minicomputers are multi-user systems that can handle the computing needs of a smaller corporation or organization. Many people use them simultaneously by means of remote terminals or personal computers.</font></p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQNRogZ_gnYBewEvaJwvG9CYpul6TjdwOb0Q1LUSzMrC9oKvtCpEd_UyjnHXomDX8WukusokMbzpJzl8RclpGp5_ANir21OJO9GTE3ujYJ3bNqvvEeL6-X92AtRDQTT_jJcgd90xYdNHlA/s1600-h/minicomputer.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQNRogZ_gnYBewEvaJwvG9CYpul6TjdwOb0Q1LUSzMrC9oKvtCpEd_UyjnHXomDX8WukusokMbzpJzl8RclpGp5_ANir21OJO9GTE3ujYJ3bNqvvEeL6-X92AtRDQTT_jJcgd90xYdNHlA/s320/minicomputer.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210952430446163522" border="0"></a><br /><p style="font-family: trebuchet ms;"><font style="color: rgb(0, 0, 0);"><font size="1">Personal computers</font></font> </p><p style="font-family: trebuchet ms;"><a name="Mainframes"></a><font style="color: rgb(0, 0, 0);" size="3">Mainframes are huge, multi-user systems designed to handle gigantic processing jobs in large corporations or government agencies.</font></p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMIznKFzxPotdL8HFP-e_wTrsw14nM4dHbTkYp4iF2dZGuZYmteqNaA7CEZ2_MFxxSmXpsmk65LuWPDsFwAkZJRdTOENSs50_cWG1VoX11leTkcgWCeeplI0mM-8gqn2onA-qJG-nTgWVH/s1600-h/mainframe.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMIznKFzxPotdL8HFP-e_wTrsw14nM4dHbTkYp4iF2dZGuZYmteqNaA7CEZ2_MFxxSmXpsmk65LuWPDsFwAkZJRdTOENSs50_cWG1VoX11leTkcgWCeeplI0mM-8gqn2onA-qJG-nTgWVH/s320/mainframe.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210952911848689186" border="0"></a><br /><p><font style="color: rgb(0, 0, 0);"><font size="1">S<font face="trebuchet ms">upercomputers</font></font></font> </p><p style="font-family: trebuchet ms;"><a name="Supercomputers"></a><font style="color: rgb(0, 0, 0);" size="3">Supercomputers are ultra fast computers designed to process hugh amounts of scientific data then display the underlying patterns that have been discovered.</font></p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8Yj1J6T3pZGPE5ySxJy9ykOMCzWRUoevf9qv07etOEmQdsNuQ31YNfYYGJtYcH-9VitUJoOBC0nxZz7R1YVOWR9bv-P1Y8tR-6vGjaaZgmEp3nDu71T7DjbgXhGdJX-pmk3FF_zRSf1wX/s1600-h/supercomputers2.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8Yj1J6T3pZGPE5ySxJy9ykOMCzWRUoevf9qv07etOEmQdsNuQ31YNfYYGJtYcH-9VitUJoOBC0nxZz7R1YVOWR9bv-P1Y8tR-6vGjaaZgmEp3nDu71T7DjbgXhGdJX-pmk3FF_zRSf1wX/s320/supercomputers2.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210953735757539986" border="0"></a></div>qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0tag:blogger.com,1999:blog-6926266186147655709.post-6671665807883236392008-06-12T03:59:00.000-07:002008-06-30T05:27:28.896-07:00Introduction<span style="font-size:130%;">INTRODUCTION</span><br /><div style="text-align: justify;"><span style=";font-family:trebuchet ms;font-size:78%;" ><br /><span style="font-size:100%;">Computers play a key role in how individuals work and how they live. Even the smallest organizations have computers to help them operate more efficiently, and many individuals use computers at home for educational, entertainment, and business purposes. In this session, you will learn the basics about computers, the history of computers, the different categories of computers, hardware and software, and maintaining your computer. You will also learn about computer applications in education and explore various technology issues that are related to computers such as security, privacy and ethics.</span><br /><br /><span style="font-weight: bold;font-size:100%;" >HISTORY</span><br /><br /></span><div style="text-align: justify;"><span style=";font-family:trebuchet ms;font-size:100%;" >Nearly 5,000 years ago the abacus emerged in Asia Minor. The abacus may be considered the first computer. This device allowed its users to make computations using a system of sliding beads arranged on a rack. Early shopkeepers used the abacus to keep up with transactions. The use of pencil and paper spread, the abacus lost its importance. Nearly twelve centuries past before the next important advance in computing devices emerged.</span><span style="font-size:100%;"> </span><span style=";font-family:trebuchet ms;font-size:100%;" > In 1642, Blaise Pascal, the 18-year-old son of a French tax collector, invented what he called a numerical wheel calculator to help his father with his duties. The Pascaline, a brass rectangular box, used eight movable dials to add sums up to eight figures long. Pascal's device used a base of ten to achieve this. The disadvantage to the Pascaline, of course, was its limitation to addition. In 1694, Gottfried Wilhem von Leibniza a German mathematician and philosopher improved the Pascaline by creating a machine that could also multiply. Like its predecessor, Leibniz's mechanical multiplier worked by a system of gears and dials.</span><span style="font-size:100%;"> </span><span style=";font-family:trebuchet ms;font-size:100%;" >It wasn't until 1820, however, that mechanical calculators gained widespread use. A Frenchman, Charles Xavier Thomas de Colmar, invented a machine that could perform the four basic mathematic functions. The arithometer, presented a more systematic approach to computing because it could add, subtract, multiply and divide. With its enhanced versatility, the arithometer was widely used up until World War I.</span><span style="font-size:100%;"> </span><span style=";font-family:trebuchet ms;font-size:100%;" > </span><span style="font-size:100%;"><span style="font-family:trebuchet ms;"> </span> </span><span style=";font-family:trebuchet ms;font-size:100%;" >The real beginnings of computers began with an English mathematics professor, Charles Babbage. Babbage's steam-powered Engine, outlined the basic elements of a modern general purpose computer and was a breakthrough concept. The Analytical Engine consisted of over 50,000 components. The basic design of included input devices in the form of perforated cards containing operating instructions and a "store" for memory of 1,000 numbers of up to 50 decimal digits long.</span><span style="font-size:100%;"> </span><span style=";font-family:trebuchet ms;font-size:100%;" > </span><span style="font-size:100%;"><span style="font-family:trebuchet ms;"> </span> </span><span style=";font-family:trebuchet ms;font-size:100%;" >In 1889, an American inventor, Herman Hollerith, created a machine that used cards to store data information which was fed into a machine and compiled the results mechanically. Each punch on a card represented one number, and combinations of two punches represented one letter. As many as 80 variables could be stored on a single card. Hollerith brought his punch card reader into the business world, founding Tabulating Machine Company in 1896, later to become International Business Machines (IBM) in 1924 after a series of mergers. Other companies also manufactured punch readers for business use. Both business and government used punch cards for data processing until the 1960's. </span><span style="font-size:100%;"> </span><span style=";font-family:trebuchet ms;font-size:100%;" >When World War II began, the governments sought to develop computers to accomplishment their potential strategic importance. This increased funding for computer development projects and hastened technical progress. In 1941, a German engineer Konrad Zuse had developed a computer to design airplanes and missiles. The Allied forces, however, made greater strides in developing powerful computers. American efforts produced a broader achievement. In 1933, Howard H. Aiken, a Harvard engineer working with IBM, succeeded in producing an all-electronic calculator. The purpose of the computer was to create ballistic charts for the U.S. Navy. It was about half as long as a football field and contained about 500 miles of wiring. It used electromagnetic signals to move mechanical parts. The machine was slow taking 3-5 seconds per calculation and inflexible in that sequences of calculations could not change; but it could perform basic arithmetic as well as more complex equations. </span><span style="font-size:100%;"> </span><span style=";font-family:trebuchet ms;font-size:100%;" >Another computer development spurred by the war was the Electronic Numerical Integrator and Computer (ENIAC). It consisted of 18,000 vacuum tubes, 70,000 resistors and 5 million soldered joints, the computer was such a massive piece of machinery that it consumed 160 kilowatts of electrical power. ENIAC was developed by John Presper Eckert and John W. Mauchl. ENIAC was a general-purpose computer. </span><span style="font-size:100%;"> </span><span style=";font-family:trebuchet ms;font-size:100%;" >In 1945, Von Neumann designed the Electronic Discrete Variable Automatic Computer (EDVAC) with a memory to hold both a stored program as well as data. This "stored memory" technique as well as the "conditional control transfer," that allowed the computer to be stopped at any point and then resumed, allowed for greater versatility in computer programming. The key element to the von Neumann architecture was the central processing unit, which allowed all computer functions to be coordinated through a single source. In 1951, the UNIVAC I (Universal Automatic Computer), built by Remington Rand, became one of the first commercially available computers to take advantage of these advances. The first computers were characterized by the fact that operating instructions were made-to-order for the specific task for which the computer was to be used. Each computer had a different binary-coded program called a machine language that told it how to operate. This made the computer difficult to program and limited its versatility and speed. Other unique features of first computers were the use of vacuum tubes and magnetic drums for data storage.</span><span style="font-size:100%;"> </span><span style=";font-family:trebuchet ms;font-size:100%;" >The invention of the transistor greatly changed the computer's development in 1948. The transistor replaced the large, cumbersome vacuum tubes. The transistor was at work in the computer by 1956. Throughout the early 1960's, there were a number of commercially successful computers used in business, universities, and government from companies such as Burroughs, Honeywell, IBM, and others. These computers also contained transistors in place of vacuum tubes. They also contained all the components we associate with the modern day computer: printers, disk storage, memory, tape storage, operating systems, and stored programs.</span><span style="font-size:100%;"> </span><span style=";font-family:trebuchet ms;font-size:100%;" >By 1965, most large business routinely processed financial information using computers. </span><span style="font-size:100%;"><span style="font-family:trebuchet ms;"> </span></span><span style=";font-family:trebuchet ms;font-size:100%;" >It was the stored program and programming language that gave computers the flexibility to finally be cost effective and productive for business use. Though transistors were clearly an improvement over the vacuum tube, they still generated a great deal of heat, which damaged the computer's sensitive internal parts. Jack Kilby, an engineer with Texas Instruments, developed the integrated circuit in 1958. The IC combined three electronic components onto a small silicon disc, which was made from quartz. Scientists later managed to fit even more components on a single chip, called a semiconductor. </span><span style="font-size:100%;"> </span><span style=";font-family:trebuchet ms;font-size:100%;" >By the 1980's, very large scale integration squeezed hundreds of thousands of components onto a chip. Ultra-large scale integration increased that number into the millions. The ability to fit so much onto an area about half the size of a dime helped diminish the size and price of computers. It also increased their power, efficiency and reliability. By the mid-1970's, computer manufacturers sought to bring computers to general consumers. These minicomputers came complete with user-friendly software packages that offered even non-technical users an arrangement of applications, most popularly word processing and spreadsheet programs..</span><span style="font-size:100%;"> </span><span style=";font-family:trebuchet ms;font-size:100%;" > </span><span style="font-size:100%;"><span style="font-family:trebuchet ms;"> </span> </span><span style=";font-family:trebuchet ms;font-size:100%;" > In 1981, IBM introduced its personal computer (PC) for use in the home, office and schools. The 1980's saw an expansion in computer use in all three arenas as clones of the IBM PC made the personal computer even more affordable. The number of personal computers in use more than doubled from 2 million in 1981 to 5.5 million in 1982. Ten years later, 65 million PCs were being used. As computers became more widespread in the workplace, new ways to harness their potential developed. As smaller computers became more powerful, they could be linked together, or networked, to share memory space, software, information and communicate with each other. Computers continue to grow smaller and more powerful.<br /><br /><br /><span style="font-size:130%;">Categories of Computers</span><br /></span> <p style="text-align: justify; font-weight: bold;font-family:trebuchet ms;"><span style="color: rgb(0, 0, 0);font-size:100%;" ><br /></span></p><p style="text-align: justify; font-weight: bold;font-family:trebuchet ms;"><span style="color: rgb(0, 0, 0);font-size:100%;" >Personal computers</span> </p><p style="text-align: justify;font-family:trebuchet ms;"><span style="color: rgb(0, 0, 0);font-size:100%;" ><a name="Personal"></a>Personal computers are desktop computers designed for an individual's use. They run programs designed to help individuals accomplish their work more productively.</span><span style="font-size:100%;"><br /></span></p><div style="text-align: justify; font-family: arial;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvLe6vTzrvAU9qk5UlhpRsuOqJCkjxgvgFJ6hGN7D3tgFBxY3KhSZN1lmeVD5ReuYMsjez2f8Qsp2TkpROVIiiHR_FkVTnKIREPOVld8CO2fADpr5SLQ71BL1wiC3IM1JRa12qIqz7A0vz/s1600-h/computer.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvLe6vTzrvAU9qk5UlhpRsuOqJCkjxgvgFJ6hGN7D3tgFBxY3KhSZN1lmeVD5ReuYMsjez2f8Qsp2TkpROVIiiHR_FkVTnKIREPOVld8CO2fADpr5SLQ71BL1wiC3IM1JRa12qIqz7A0vz/s320/computer.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210951556937186802" border="0" /></a><p style="text-align: center;"><br /></p><p> </p><p style="font-weight: bold;font-family:trebuchet ms;"><span style="color: rgb(0, 0, 0);font-size:100%;" >Servers</span> </p><p style="font-family: trebuchet ms;"><a name="Servers"></a><span style="color: rgb(0, 0, 0);font-size:100%;" >Servers are not designed to be used directly. They make programs and data available for people hooked up to a computer network, a collection of computers connected together so that they can exchange data.</span></p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisOz6Ttpmfvg7xOc3oVLnDCm9xlEV542HBAI0bgiozI5f6yMZ2iq2i5YIn4mO0DhnwzSFmxrtxQOH8xCqaVcZGgfV-h5PUyGvY8QKQMS4Xf_oxU4htX3s66q0K3E5v55IJPLHWbS8ukHJa/s1600-h/server.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisOz6Ttpmfvg7xOc3oVLnDCm9xlEV542HBAI0bgiozI5f6yMZ2iq2i5YIn4mO0DhnwzSFmxrtxQOH8xCqaVcZGgfV-h5PUyGvY8QKQMS4Xf_oxU4htX3s66q0K3E5v55IJPLHWbS8ukHJa/s320/server.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210951971910014418" border="0" /></a><br /><p style="text-align: left;"> </p><p style="font-family:trebuchet ms;"><span style="color: rgb(0, 0, 0);font-size:130%;" >Minicomputers</span> </p><p><a name="Minicomputers"></a><span style="color: rgb(0, 0, 0);font-family:trebuchet ms;font-size:100%;" >Minicomputers are multi-user systems that can handle the computing needs of a smaller corporation or organization. Many people use them simultaneously by means of remote terminals or personal computers.</span></p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQNRogZ_gnYBewEvaJwvG9CYpul6TjdwOb0Q1LUSzMrC9oKvtCpEd_UyjnHXomDX8WukusokMbzpJzl8RclpGp5_ANir21OJO9GTE3ujYJ3bNqvvEeL6-X92AtRDQTT_jJcgd90xYdNHlA/s1600-h/minicomputer.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQNRogZ_gnYBewEvaJwvG9CYpul6TjdwOb0Q1LUSzMrC9oKvtCpEd_UyjnHXomDX8WukusokMbzpJzl8RclpGp5_ANir21OJO9GTE3ujYJ3bNqvvEeL6-X92AtRDQTT_jJcgd90xYdNHlA/s320/minicomputer.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210952430446163522" border="0" /></a><br /><p style="font-weight: bold;font-family:trebuchet ms;"><span style="color: rgb(0, 0, 0);font-size:100%;" >Personal computers</span> </p><p style="font-family: trebuchet ms;"><a name="Mainframes"></a><span style="color: rgb(0, 0, 0);font-size:100%;" >Mainframes are huge, multi-user systems designed to handle gigantic processing jobs in large corporations or government agencies.</span></p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMIznKFzxPotdL8HFP-e_wTrsw14nM4dHbTkYp4iF2dZGuZYmteqNaA7CEZ2_MFxxSmXpsmk65LuWPDsFwAkZJRdTOENSs50_cWG1VoX11leTkcgWCeeplI0mM-8gqn2onA-qJG-nTgWVH/s1600-h/mainframe.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMIznKFzxPotdL8HFP-e_wTrsw14nM4dHbTkYp4iF2dZGuZYmteqNaA7CEZ2_MFxxSmXpsmk65LuWPDsFwAkZJRdTOENSs50_cWG1VoX11leTkcgWCeeplI0mM-8gqn2onA-qJG-nTgWVH/s320/mainframe.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210952911848689186" border="0" /></a><br /><p style="font-weight: bold;"><span style="color: rgb(0, 0, 0);font-size:100%;" >S<span style="font-family:trebuchet ms;">upercomputers</span></span> </p><p style="font-family: trebuchet ms;"><a name="Supercomputers"></a><span style="color: rgb(0, 0, 0);font-size:100%;" >Supercomputers are ultra fast computers designed to process hugh amounts of scientific data then display the underlying patterns that have been discovered.</span></p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8Yj1J6T3pZGPE5ySxJy9ykOMCzWRUoevf9qv07etOEmQdsNuQ31YNfYYGJtYcH-9VitUJoOBC0nxZz7R1YVOWR9bv-P1Y8tR-6vGjaaZgmEp3nDu71T7DjbgXhGdJX-pmk3FF_zRSf1wX/s1600-h/supercomputers2.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8Yj1J6T3pZGPE5ySxJy9ykOMCzWRUoevf9qv07etOEmQdsNuQ31YNfYYGJtYcH-9VitUJoOBC0nxZz7R1YVOWR9bv-P1Y8tR-6vGjaaZgmEp3nDu71T7DjbgXhGdJX-pmk3FF_zRSf1wX/s320/supercomputers2.jpeg" alt="" id="BLOGGER_PHOTO_ID_5210953735757539986" border="0" /></a><br /><br /><span style="font-family:trebuchet ms;">source</span>:<span style="font-style: italic;font-family:trebuchet ms;" >http://dragon.ep.usm.edu/</span><br /><br /><p><span style="font-family:trebuchet ms;"> </span> </p></div></div></div> <!-- #EndEditable -->qnxhttp://www.blogger.com/profile/14919378544171632877noreply@blogger.com0