test-drb

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101090 discussions

Can someome explain how arithmetic works?

by CLASSICCMP＠trailing-edge.com

Daniel Seagraves wrote, in his classic style of leaving the body of the message devoid of any any actual context as to what he's asking about and requiring a reference to the Subject line: >Subject: Can someome explain how arithmetic works? >Need this for my emulator, and nobody can explain to me how it works, and >I can't find any documentation that's useful to me. Specifically, I need stuff >like "you shift left and then check the last bit" etc. etc. Basically, I have >a bunch of ones and zeroes and I have to know how to add/subtract/multiply/ >divide with them. A *very* popular book for introducing this subject to students these days is _Computer Arithmetic: Algorithms and Hardware Designs_, by Behrooz Parhami. It's a pedantic, general purpose introduction, with an emphasis on conveying a true understanding of the subject through how the bits are actually banged about. An even more pedantic introduction is Donald Knuth's _The Art of Computer Programming, Vol 1: Fundamental Algorithms_. It's probably not so good as a introduction if you're really unfamiliar with the subject already, but it's a true classic in the field, and anyone who has worked in the field goes back to it every so often for some deep insight. For example, I just browsed through it a couple days ago for some grokking of how negative number base arithmetic works. Neat feature: no sign bit necessary! Another good reference, if you've already got some experience with computer architecture books and want to leverage this knowledge, is the IEEE Tutorial titled simply _Computer Arithmetic_ and edited by Earl E. Swartzlander. There's also Kai Hwang's _Computer Arithmetic: Principles, Architecture, and Design_ and Israel Koren's _Computer Arithmetic Algorithms_. I suspect that you just want a cheat-sheet for a few specific applications, in which case there's probably a Schaum's outline paperback that will get you by but without conveying any real understanding about how it works or why it works the way it does. I'm sure your local library has some similar workbook-style textbooks. Perhaps intermediate between the dumbed-down level of Schaum's Outlines and the high-and-lofty ivory tower view of Knuth would be a good numerical analysis text intended for scientists who have to learn the basics of how computers do arithmetic, and how this differs from traditional school-book arithmetic. _Numerical Recipes_ doesn't quite fit the bill, but when I was an undergrad I took several numerical analysis courses and all the textbooks had good, but terse, introductions to computer arithmetic, both fixed and floating-point. Again, I'm sure your local library has some good books. -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

25 years, 11 months

Woz and his 6 chips...

by paulrsm＠ameritech.net

---------- > From: Mike Cheponis <mac(a)Wireless.Com> > To: classiccmp(a)classiccmp.org > Subject: Re: Woz and his 6 chips... > Date: Friday, June 02, 2000 12:14 AM > > Ladies & Gents, now I -gotta- know: What were those 6 chips, and is there a > schematic somewhere? If you want to see a nice picture, see eBay auction 341188950 (ends June 3).

25 years, 11 months

ASCII Art Golden Gate Bridge & Plane

by dastar＠siconic.com

I took a photo of an ASCII art poster I have featuring the Golden Gate bridge and an airplane flying over it: http://www.siconic.com/crap/ascii_bridge.jpg It's made of up roughly 7 x 8 squares of wide carriage printer paper and is roughly 9 feet wide by 7 feet high. It's yellowed with age because it had been hanging on the wall of the person who originally printed it for I believe a couple decades or so. Sellam International Man of Intrigue and Danger ------------------------------------------------------------------------------- Looking for a six in a pile of nines... Coming soon: VCF 4.0! VCF East: Planning in Progress See http://www.vintage.org for details!

25 years, 11 months

ASCII Art Golden Gate Bridge & Plane

by pete＠dunnington.u-net.com

On Jun 2, 15:23, John Foust wrote: > I think this is on an RSX ASCII collection tape I got from > someone or somewhere. In the "readme" FILENN.IDX, it's the > largest file: > > FILE14.LST 12,405 * Golden Gate Bridge > > where 12,405 records translated to 1,659,857 bytes. I'd be > glad to send a zipped version to anyone who wants it. > > By comparison, the popular Moon picture is 950,283 bytes, and > the Einstein is 348,400 bytes. I'd like copies of these, if you can make them available... -- Pete Peter Turnbull Dept. of Computer Science University of York

25 years, 11 months

OT: Looking for Cap'n Crunch 2600Hz whistle

by dastar＠siconic.com

I'm looking for one of the original Cap'n Crunch cereal whistles that could produce the 2600Hz tone. If you know the story of John Draper (a.k.a. Cap'n Crunch) then you know what I'm talking about. I'd also like to get a hold of the box the whistle came in. I'm also looking for the October 1971 issue of Esquire magazine that featured the article with John Draper talking about the "blue box". If anyone has any idea where I might find these items, please e-mail me directly at <sellam(a)vintage.org>. Thanks! Sellam International Man of Intrigue and Danger ------------------------------------------------------------------------------- Looking for a six in a pile of nines... Coming soon: VCF 4.0! VCF East: Planning in Progress See http://www.vintage.org for details!

25 years, 11 months

AppleSoft BASIC

by foo＠siconic.com

Here's something I pondered the other day: Why is AppleSoft BASIC called "AppleSoft" BASIC? ^^^^ Does this have something to do with the fact that Microsoft designed it? I can't think offhand of any other Apple software product that fell under the designation of "AppleSoft". Something tells me Eric may know this. Sellam International Man of Intrigue and Danger ------------------------------------------------------------------------------- Looking for a six in a pile of nines... Coming soon: VCF 4.0! VCF East: Planning in Progress See http://www.vintage.org for details!

25 years, 11 months

OT: Archiving data (LONG)

by jfoust＠threedee.com

Regarding recording data on analog 35mm film, below is a recent excerpt from a microscopy mailing list, where people were discussing the use of film to record detail, as opposed to CCD imaging techniques: > To begin to answer Jeremy's question directly, we need to know > how much detail a Technical Pan negative can record. The figures > depend on processing technique and the test object luminance and > contrast, but the modulation transfer function figures published by > Kodak indicate that a spatial frequency in excess of 200 cycles per > mm is easily recordable. For a test object with contrast 100:1 they > quote 320 line pairs per mm. The CCD pixel spacing required to > achieve this feat would be 640 pixels per mm. That equates to a > requirement for 15360 x 23040 pixels to match the resolving power > of a 24x36mm Technical Pan exposure. That's 0.35 Giga pixels in > round numbers. - John

25 years, 11 months

Looking for data sheet for Zilog 8530 Serial chip

by allisonp＠world.std.com

>A search of the web yielded lots of links, but no datasheet. I want to know >how to program it and its electrical characteristics. You know, the stuff >on a datasheet. Zilog's web site doesn't have it. 8530 is the Zilog SCC chip, as is the 8030. The differ only in bus interface. The 8530 is the non multiplexed bus part. It's a dual channel serial device with DMA and interrupt logic for Z80 series cpus. Programming of the functions are similar to Z80 SIO and related parts in a general way. It's a nontrivial device to use. Contact Zilog for data or check their page under SCC. >[ Its the chip used in the Apple Lisa and Mac and LOTS of other devices. ] You sure of this?? It's not really friendly to the 68k buses. Allison

25 years, 11 months

Defining Disk Image Dump Standard

by xds_sigma7＠hotmail.com

Hmm, if someone writes a way to do all the archiving, I'd be happy to provide my 4381 for some serious processing power ;p Will J ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com

25 years, 11 months

Please help ID this Mac board--I hope it's old enough for the list!

by dhquebbeman＠theestopinalgroup.com

Sounds like a cache card for a PowerPC-based Mac. -dq > -----Original Message----- > From: Stan Perkins [mailto:stan@netcom.com] > Sent: Thursday, June 01, 2000 6:22 PM > To: classiccmp(a)classiccmp.org > Subject: Please help ID this Mac board--I hope it's old enough for the > list! > > > Hello all, > > I just came across this small PCI type board, labeled: > > APPLE COMPUTER INC. > 820-0510-A c1993 > > It also has a chip on it with the label: > > 341S0021 > c 1983-93 Apple > ^ > | > |-----That's why I'm hoping it's old enough to qualify :-) > > Anyway, on one side of the PCB it's got four large quad flat > pack chips, > from Philips, TI, VLSI, and BT, and on the other side (with the Apple > labeled chip I mentioned earlier) it has two rows of 8 each Toshiba > TC528128BJ-80 RAM chips. On the back end it has a DB-15F > connector (like > the old Apple monitor connector) and two round DIN connectors > labeled "S > IN" and "S OUT" with 7 female contacts each. > > It came in a box labeled DOS Compatibility Card for Macintosh, but I'm > beginning to think it's not. > > Any clues are greatly appreciated! > > Thanks, > Stan >

25 years, 11 months

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