test-drb June 2016

test-drb@ccmp.vtda.org

196 participants
290 discussions

by dave＠661.org

I have a 9-slot VME backplane for sale or trade. It weighs about 3 pounds when packed. Pictures at https://www.flickr.com/photos/32548582 at N02/albums/72157670027920776 -- David Griffith dave at 661.org A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail?

7 years, 11 months

HP Series-80 computers - PRM-85 board case? ... maybe!

by Martin.Hepperle＠dlr.de

Hi, I own PRM-85 boards for my HP-85 and 86 machines. While they are very useful extension modules for these computers, they lack a proper case. I hate to destroy a working interface or memory module just for the case. I read in this list that there are more people interested in such a case. So I designed a replica case for 3D printing, but did not yet try it out. I do not own a 3D printer and the commercial services calculate between $20 to $100 for one shell (upper/lower). This is a bit expensive for some trials, as I expect that the 3D design would need some iterative refinement to obtain a "perfect" case. So: if someone owning a 3D printer and a PRM-85 board is interested in helping me to refine the design by making a test print I could supply the STL files for upper and lower shells. As a "thank-you" I would expect feedback to improve the design. Regards, Martin Martin {.} Hepperle {at} mh-aerotools {dot} de

7 years, 11 months

CDC 6600 emulation - was Re: How do they make Verilog code for unknown ICs?

by jnc＠mercury.lcs.mit.edu

> From: Dwight Kelvey > The RIS[C]/CISC is really not even relevant in todays processors since > the main limiting factor is memory access bandwidth and effective use > of caches. Memory bandwidth has often been the limiting factor over the complete timeline of CPU's/systems. (It would be interesting to draw up a timeline, showing the periods when it was, and was not.) Yes, caches can help a lot, but inevitably they will miss (depending on the application, more or less often). The RISC/CISC thing actually is kind of relevant to this, because RISC focuses on getting the CPU cycles to be as fast as possible, and that kind of implies simpler instructions --> more instructions to get a particular task done. That was part of the motivation for microcoding, back when it was invented; at that point in time, logic was fast, memories were slow, so more complex instructions made better use of memory bandwidth - especially since this was pre-caches. (It also made binary code 'denser', which was important back then, with much smaller memories.) However, more complex instruction sets made the CPU more complicated; microcoding helped deal with that. The 801's breakthrough, at a very high level, was to see the whole system, and try and optimize across the compiler as well as the instruction set, etc, etc. They also realized that people had been going CISCy for so long that people had to some degree forgotten why, and that that assumption needed to be re-examined - especially in light of the then-current logic/memory speed balance, which had shifted towards memory at that particular point in time. Noel

7 years, 11 months

Leaking DEC VR201 monochrome monitor?

by billdegnan＠gmail.com

I picked up a DEC VR201 display today, it was leaking a highly corrosive brown liquid. So corrosive it burned my skin painfully / immediately and I had to wash hands thoroughly. Anyone come across a display that leaked a corrosive liquid like that? The display was stored in its original box, so I don't think the brown liquid was from something stored on top of it, but I don't know for sure. Bill -- @ BillDeg: Web: vintagecomputer.net Twitter: @billdeg <https://twitter.com/billdeg> Youtube: @billdeg <https://www.youtube.com/user/billdeg> Unauthorized Bio <http://www.vintagecomputer.net/readme.cfm>

7 years, 11 months

WTD: S100 Static RAM card

by philip＠neoncluster.com

Hi all, I?ve been struggling getting a 64k Dynamic RAM card back up and working in my IMSAI 8080. In fact I?m giving up on the DRAM card in this system and have decided to start looking for a SRAM card that can get the IMSAI up to 56k. In terms if SRAM cards, I presently have: 2 x Problem solver RAM16 cards - both seem to be working. 2 x 8K RAM cards - both seem to be working. Less cards generating heat, and putting stress on the old power supply is obviously best, so I?d be looking for either: - 1 x 16k SRAM card (for a total of 4 RAM cards (3 x 16k + 1 x 8k) in my system). A PSS RAM16 would be preferred for sake of consistency, but obviously not crucial. - 1 x 32k SRAM card (for a total of 3 RAM cards (1 x 32k, 1 x 16k + 1 x 8k) in my system) - 1 x 64k SRAM card that can have the last 8k bank turned off I would love to hear from anyone with one of the above cards who would be willing to pass it on. Much thanks for your time. Best regards Philip

7 years, 11 months

CDC 6600 - Why so awesome?

by jnc＠mercury.lcs.mit.edu

> From: Brian Walenz >> Werner Buchholz (editor), "Planning a Computer System: Project >> Stretch", McGraw-Hill, New York, 1962 > http://ed-thelen.org/comp-hist/IBM-7030-Planning-McJones.pdf Yeah, I found that _after_ I sent the email, sigh... >> Speaking of books, there's also a CDC 6600 book: >> Jim E. Thornton, "Design of A Computer: The Control Data 6600", >> Scott, Foresman, Glenview, 1970 > http://www.textfiles.com/bitsavers/pdf/cdc/6x00/books/DesignOfAComputer_CDC… Didn't know that one was online too - excellent. >> Really gotta do that Bibliography! > Where is this 'computer history wiki', anyway? http://gunkies.org/wiki/Main_Page Note; automatic account creation is disabled to prevent spamming issues. You have to email Tore directly - and he is often busy, so it may take a bit. Noel

7 years, 11 months

Data General 8000-series logic in my Nova 3?!

by shadoooo＠gmail.com

Hello Mark, when you are ready with your machine up and running, you could try to use on a real Nova 3 the tool I wrote to raw read/write disks and tapes through the serial port. You just need a PC (linux preferred) and Python installed (plus serial port module). Then you should be able to dump the disk to image for SIMH, and eventually to write back an image to the disk. Thanks Andrea

7 years, 11 months

Data General 8000-series logic in my Nova 3?!

by jnc＠mercury.lcs.mit.edu

> From: Mark J. Blair > An interface card schematic has appeared in my inbox as if by magic. If that allows you to create a list of what various 8000-series chips do (or if you've since located one), that would be a good thing to have available online. If you have (or create) one, we can stick it on the Computer History wiki... Noel

7 years, 11 months

where to find DEC ECO's for KB11-A?

by jnc＠mercury.lcs.mit.edu

> From: Al Kossow aek at bitsavers.org > which one? > 1974_Field_Service_Technical_Manual_Dec74.pdf > is already on line under handbooks Dat be de one. Alas for the OP, it doesn't seem to contain any PDP-11 stuff (well, a bit on the RK11-C, etc, but nothing on any processor, at least that I could see). FWIW, it's available online on an indexed, page-by-page basis at: http://www.pdp8online.com/bklatt/TechTips.html Worth looking through. Some of them are amusing, like "Disk Destruction Made Simple" and "DECtape Reels Falling Off Drive". Noel

7 years, 11 months

library/book carts available

by jwest＠classiccmp.org

Maybe a year ago I got two metal 3 shelf library carts on wheels, to hold the manuals that were related to whatever machine I was working on at the time. Its extremely useful to have all the manuals at hand on a rolling stand when you're moving around working on the beast. I have not seen any for sale since then at a reasonable price (which I'd say is $100 or less). I just stopped at a place here in St. Louis, and I see they have 8 of these "library/book carts" available. They are basically in mint condition, and most of them come with old red binders on 2 of the 3 shelves. The binders are interesting - these are those old ones with sort of cloth surfaces and heavy metal latches inside. All the binders are about 3 or 3.5 inch wide. A typical place I see these type of binders is in machine shops and the like, holding press setup instructions and such. The binders are old, but the carts are basically new looking. The carts are 42.5" tall, 31" wide, and 13" deep. The carts hold books on one side only, and the height of each shelf between the next is 11 & 5/8. If your binders are taller than that they won't fit ;) $75 each. Here is a link to an almost-but-not-quite-identical cart: http://tinyurl.com/huamv7e I'm buying 2 of these for myself, leaving six. I'd be happy to purchase and hold for a while if someone non-local wants some, but it's probably not economical to ship them. I could deliver one or two to VCFMW this year perhaps. J

7 years, 11 months

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test-drb June 2016