test-drb August 2006

test-drb@ccmp.vtda.org

216 participants
517 discussions

A little more Am2900 learning/evaluation kit info

by vdub6＠comcast.net

Came across one of your old postings. Are you still looking for an AMD AM2900 Evaluation and Learning Kit? I have one I might be persuaded to part with. Let me know. Thanks, Mark

17 years, 11 months

MO support

by dgy＠DakotaCom.Net

*Aside from Linux*, are there any OS's with suport for MO drives with > 512B sectors? I know older Macs would support some of the PMO drives but I think that required some third party support... Unfortunately (?) W2K seems to be the only practical option I've found :-(

17 years, 11 months

Megadata available

by wdonzelli＠gmail.com

Tomorrow I am turning in my pile of white elephants to the scrapyard. Of the pile, I only managed to sell one, on Ebay, for less than scrap value (20 bucks - oh boy...). So away they go. I figure I will hold one, and make a last ditch sales pitch to clear my conscious. Anyway, these Megadata minicomputers are pre-microprocessor TTL designs, and look to be from the mid 1970s. The more I look at the boards, they look like twelve bit machines. These are rack mount units about 4U high. These have no fancy front panels - just blue covers with a reset button, and two LEDs. There are comm ports on the back. The software is contained on a board with a bunch of 1702A EPROMs. RAM is an array of 48 2101s. I have zero docs on these. So anyway, if anyone wants to rescue (in the true sense) this last Megadata, please contact me TONIGHT, as I leave for the junkyard around 10 AM tomorrow. And yes, I would like something a bit better than scrap value... -- Will

17 years, 11 months

Anyone recognize this PCB?

by dm561＠torfree.net

I take it that despite the 35+ replies, no one actually recognized this board, or wants to make an educated guess? BTW, in view of the apparent confusion and at least one incorrect opinion, the non-hybrid D-sub S and P refer to female (socket) and male (pin or plug, depending on manufacturer) _connectors_, not the shell. Same thing for many similar connectors, such as XLR & DIN, where the shell is normally the opposite gender of the connectors. So, the DB25S below is the same as found on the back panel of most of our old RS-232 terminals & systems (or a pre-USB PC printer port). -----------------Original Message----------------------------------------------------------------- I'm hoping someone can ID this interesting board (sorry, no pix avail). 16Bit ISA (full-length) DB25S Connector 20pin header socket 10 pos DIP SW 10 seg green LED bar graph 3 sets of jumper pins 80186 CPU 2 x XC2064 XILINX FPGAs Pair of IDC 7130/7140 (1Kx16 dual-port memory) 2 x 256x8 SIPPs C8208 DRAM controller 2 x 27256 EPROMs 2 x DS1225Y BBU SRAM 2 x LH0033 Fast FET buffers (12 pin metal cans) Misc 74LS & F glue chips Nothing recognizable in the EPROMS or SRAMS; 1 EPROM is blank (erased/defective?) Ring any bells with anyone, or time to scrap for parts? mike

17 years, 11 months

Simon Computer

by marvin＠rain.org

I'm curious what the group thinks about offering a kit for the Simon Computer that would include a schematic, parts list, and perhaps construction instructions. For those of you who aren't aware, Simon is a five bit relay computer designed by Edmund Berkeley. A series of articles about how the computer worked was published in the Oct 1950 - Sept 1951 issues of Radio Electronics. I've thought about it, but I would guess the parts cost alone would be in excess of $300.00, and maybe considerably more. On the other hand, it is a really cool computer :).

17 years, 11 months

Classic Mac emulation (was Re: Microkernels (WAS RE: New to the list.))

by ethan.dicks＠gmail.com

On 8/22/06, Zane H. Healy <healyzh at aracnet.com> wrote: > Does anyone have any > experience with it? How is the frame rate? I really like the look > of Sheepshaver, it looks to be just what I'm after. Didn't it > originally run on the Amiga? ISTR, having it on my A3000. I don't know about "Sheepshaver", but "Shapeshifter" was a Mac emulator I used on my A3000 in 1996/1997. I even used it with SANA2 drivers to run Netscape 0.8 on the MacOS - very cool when Amiga web browsers were quite primitive. -ethan

17 years, 11 months

stack smashing Was: Re: Scanning Formats (TIFF vs. JPEG) (Way OT)

by compoobah＠valleyimplants.com

Dave wrote: > When I was in university (70s), I had a hot-dog cooker which cooked > weiners by connecting them across the 110v AC mains. This was a > commercially produced device. > [snip] Did it light up a pickle when the hot-dog was done?

17 years, 11 months

Sinclair ZX80 questions

by pete＠dunnington.plus.com

On Aug 22 2006, 17:57, Jules Richardson wrote: > Rob O'Donnell wrote: > > At 08:30 22/08/2006, Jules Richardson wrote: > > > >> You know, my prototype Torch Z80 disk unit has power out at the back; > >> I can't remember whether the production ones were like that or not. It > >> had never occurred to me that someone would want to power the machine > >> from it! They were all like that, including all the production ones, and the fitting instructions explained how to *remove* the Beeb's own PSU completely, and fit the cable to run it off the Torch disk pack. It was not a good move on Torch's part; I've seen several Beebs completely destroyed as a result of bad PSUs or miswiring. A common problem was that the Z80 card is supposed to fit inside the Beeb, on PCB mounts stuck to the case top with sticky pads. Of course, sometimes those unstick and the Z80 card -- component side down -- falls onto the Beeb's motherboard and shorts things out. If you're lucky, it crashes the Beeb. If you're unlucky, it shorts out the power. This makes the Torch switch-mode detect the over-current and shut down, and in typical SMPSU fashion, immediately try to restart. Unfortunately the regulation in that situation isn't too good and you often get a voltage overshoot. The Beeb's LSTTL does not take kindly to having 9V (approx) pumped into it. I've repaired a couple that had that happen; one of them ended up with every single IC except the NMOS socketed and replaced. It made a nice demo unit for our workshop and an excellent practice setting for our YTS trainee :-) Another one is that Torch used standard 3-core mains cable for the PSU connections, and more than one person, faced with a dismantled system, has connected this "mains cable" to the mains. > I'm still surprised that there were any beebs incapable of running the Torch > board from their own PSU though. I believe there was a change to PSU spec at > some point early in the beeb's life though, so maybe very early systems > couldn't cope. The maximum current drawn by the Torch Z80 is nominally close to the spare capacity of the Beeb's SMPSU, so they were playing safe in case people had other expansions. Besides, there were still Beebs with linear supplies around when they built the prototypes in early 1982. Yes, there were several PSUs. The original was a black linear power supply, and there were three variants of that (two matt black, one glossy). One "power adaptor/converter" originally used in Model As was so notorious for running hot in upgraded machines or Model Bs that it was nicknamed the "adaptor/exploder", after the failure mode it exhibited. I remember being told in 1982 that "hardly any of these remain in the field". I wonder why. Anyone with a linear supply was offered a free switch-mode upgrade if they fitted a DFS upgrade, or a few other things. The original SMPSU was quite a nice unit made by Astec. This is in a golden coloured metal case, or frame you might say, as it's open on three sides -- which doesn't matter because it's enclosed in the plastic case. Later Acorn had these made under license by BSR, but once again the quality suffered. Most of the BSR units have poorer regulation and less spare capacity than the Astec ones. -- Pete Peter Turnbull Network Manager University of York

17 years, 11 months

September Livermore Swapmeet

by marvin＠rain.org

I'm planning on going up to the Livermore swapmeet again on Sunday, September 3 to browse, drop stuff off, and meet some classic computer people. If anyone buys some stuff from VCM (http://www.vintagecomputermarketplace.com/) and wants to save on shipping by meeting at the swapmeet, just let me know. I think the swapmeet opens to buyers at 7:00AM and more information is available on the web at http://www.livermoreark.org/swap/swap.html.

17 years, 11 months

293xx

by ploopster＠gmail.com

Is there anyone around who has datasheets for the AMD Am29300-series chips, and wouldn't mind scanning them for me? I'm most interested in the sheets for the Am29331 sequencer and the Am29332 ALU. Thanks. Peace... Sridhar

17 years, 11 months

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test-drb August 2006