Newsgroups: alt.folklore.computers From: ehrice@his.com (Edward Rice) Subject: Re: Computer Education (was: Historian's Soapbox Again) Message-ID: Organization: NDS Date: Sat, 26 Aug 2000 02:01:50 -0400 References: <397243A7.5551@bellsouth.net> <397e0bf5$1@news.ucsc.edu> <8llr6g$s4j$1@nnrp1.deja.com> <8lpqcf$au9$1@news.kersur.net> <39861123$1@news.ucsc.edu> <3986DF89.E03AAFC0@cmc.com> <39879BAF.D50903B5@cmc.com> NNTP-Posting-Host: max1h-18.his.com X-Trace: 26 Aug 2000 02:01:50 -0400, max1h-18.his.com Lines: 48 X-Authenticated-User: ehrice Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!newsfeeds.belnet.be!news.belnet.be!xfer13.netnews.com!netnews.com!newspeer.monmouth.com!news.lightlink.com!news1.his.com!news.cs.jhu.edu!vienna7.his.com!user Xref: chonsp.franklin.ch alt.folklore.computers:62586 In article <39879BAF.D50903B5@cmc.com>, Lars Poulsen wrote: > Oops, make that URL http://www.cmc.com/lars/engineer/how_comp/ . > ^^^^^^^^ We used to start kids (young high-schoolers, 14-16 years old) off -- before they graduated to front-panel, hands-on experience with a Honeywell DDP-316 -- with something called "The Four-Bit Computer," which I invented. It was purely a blackboard exercise, but it worked well (with a certain amount of hand-waving) for teaching a classroom of kids where we'd be going with assembler language. IIRC, Four-Bit had four words of four bits, each word split into two bits of op-code and two bits of addressing. No modifiers, and an implicit accumulator which didn't require specification. The instructions when we started off were Load, Store, Transfer, and Halt. Generally, thanks to the intellectual purity of the model (and the fact that there were only sixteen bits to mess with), students fully understood the concept in about fifteen minutes. Because Four-Bit was on the blackboard, it was easy to wire on an additional bit into the memory (and explain in a later session why five-bit words weren't such a great idea), and to add additional words. For the sharper students, we'd first add four additional words of memory and then let them figure out that addressability was an important design issue to be addressed. It was also possible, even before they saw a functioning computer, to show them how useful test and transfer instructions could be -- and because Four-Bit was on a blackboard, redefining the op-codes was the work of just a few seconds. It was an excellent pedagogic tool. It usually took just one session with Four-Bit before the kids were ready to program their own first blinking-lights program. They'd key that one into the front-panel of the 316, and then single-step their way through the program to see what mischief they had wrought. One of our brighter students -- and the only one whose parole board I ever needed to write a letter to! -- implemented a neat program that raced bits across two registers to see which would get to the end of the register first -- I think he may have used the low-order bit of the machine's clock as his random number generator. From first introduction of what a "bit" was to running their own assembler source on a system which they were operating themselves took a total of about three sessions -- four or five hours. ###### From: jmfbahciv@aol.com Newsgroups: alt.folklore.computers Subject: Re: Computer Education (was: Historian's Soapbox Again) Date: Sat, 26 Aug 00 11:28:56 GMT Organization: UltraNet Communications, Inc. Lines: 79 Message-ID: <8o8kd9$t1q$3@bob.news.rcn.net> References: <397243A7.5551@bellsouth.net> <397e0bf5$1@news.ucsc.edu> <8llr6g$s4j$1@nnrp1.deja.com> <8lpqcf$au9$1@news.kersur.net> <39861123$1@news.ucsc.edu> <3986DF89.E03AAFC0@cmc.com> <39879BAF.D50903B5@cmc.com> X-Trace: 8Ti/YW+z4Tt892u6svfu6jSPkTDbikkhbhbulVvrPzo= X-Complaints-To: abuse@rcn.com NNTP-Posting-Date: 26 Aug 2000 14:32:09 GMT X-Newsreader: News Xpress Version 1.0 Beta #4 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!newsfeeds.belnet.be!news.belnet.be!xfer13.netnews.com!netnews.com!feed1.news.rcn.net!rcn!207-172-255-141 Xref: chonsp.franklin.ch alt.folklore.computers:62581 In article , ehrice@his.com (Edward Rice) wrote: >In article <39879BAF.D50903B5@cmc.com>, >Lars Poulsen wrote: > > > Oops, make that URL http://www.cmc.com/lars/engineer/how_comp/ . > > ^^^^^^^^ > >We used to start kids (young high-schoolers, 14-16 >years old) off -- before >they graduated to front-panel, hands-on experience with >a Honeywell DDP-316 >-- with something called "The Four-Bit Computer," >which I invented. It was >purely a blackboard exercise, but it worked well (with a certain amount of >hand-waving) for teaching a classroom of kids where we'd be going with >assembler language. > >IIRC, Four-Bit had four words of four bits, each word split into two bits >of op-code and two bits of addressing. No modifiers, and an implicit >accumulator which didn't require specification. The instructions when we >started off were Load, Store, Transfer, and Halt. Generally, >thanks to the >intellectual purity of the model (and the fact that >there were only sixteen >bits to mess with), students fully understood the concept in about fifteen >minutes. > >Because Four-Bit was on the blackboard, it was easy to wire on an >additional bit into the memory (and explain in a >later session why five-bit >words weren't such a great idea), and to add additional words. For the >sharper students, we'd first add four additional words of memory and then >let them figure out that addressability was an important >design issue to be addressed. > >It was also possible, even before they saw a functioning computer, to show >them how useful test and transfer instructions could be -- and because >Four-Bit was on a blackboard, redefining the op-codes was the work of just >a few seconds. It was an excellent pedagogic tool. Wow. I'd pay you money just to take that course today. > >It usually took just one session with Four-Bit before the kids were ready >to program their own first blinking-lights program. They'd key that one >into the front-panel of the 316, and then single-step >their way through the >program to see what mischief they had wrought. And that's the key to learning and why I think lights are so important. > One of our brighter >students -- and the only one whose parole board I ever needed to write a >letter to! -- implemented a neat program that raced bits across two >registers to see which would get to the end of the register first -- I >think he may have used the low-order bit of the machine's clock as his >random number generator. That kid had potential. > >From first introduction of what a "bit" was to running their own assembler >source on a system which they were operating themselves took a total of >about three sessions -- four or five hours. And should be in every CS101 as far as I'm concerned. My mother tells me that my nephew knows a lot about computers. He's never seen the inside of a PC, has no notion about address and contents of an address, and gives me the willies when his solution to analyzing a computer glitch is to reinstall one piece of it . Printer has a hardware problem? Reinstall the software, over, and over, and over,.... /BAH Subtract a hundred and four for e-mail.