test-drb May 2011

test-drb@ccmp.vtda.org

162 participants
224 discussions

by cclist＠sydex.com

I'm working with an old data sample (ca. 1979) to a piece of equipment that I do not have access to. I've identified some bits and pieces of code and am trying to identify the processor. Here's what I know. The processor is big-endian and appears to be byte-addressable. The opcode for CALL appears to be D3 xx xx, where xxxx is the address of the destination. 2C appears to be load immediate instruction and is also 3 bytes long. The code doesn't look tight enough to be a p-code implementation of any sort. Does this ring any bells to anyone? --Chuck

13 years, 2 months

New rsync mirroring at trailing-edge.com

by shoppa＠trailing-edge.com

Last weekend I promised to enable rsync access to the archives (and mirrors) here. I've set up the following rsync (no password required) archive sets here: ftp : Public rsync access to ftp://ftp.trailing-edge.com/ area pdp-10-tape-images : public rsync access to the PDP-10 tape images, i.e. http://pdp-10.trailing-edge.com/ bitsavers-mirror : public rsync access to my local bitsavers mirror, i.e. http://bitsavers.trailing-edge.com/ Suggested rsync commands would be, for example: mkdir ./pdp-10-tape-images rsync -rlptu -v www.trailing-edge.com::pdp-10-tape-images ./pdp-10-tape-images mkdir ./ftp.trailing-edge.com rsync -rlptu -v www.trailing-edge.com::ftp ./ftp.trailing-edge.com mkdir ./bitsavers-mirror rsync -rlptu -v www.trailing-edge.com::bitsavers-mirror ./bitsavers-mirror Realistically the pdp-10-tape-images and ftp sites don't change often, butm my bitsavers mirror is kept up to date. I like to think my outgoing bandwidth (20 Mbit) is pretty much infinite, this looks like a good way to find out :-) ftp racks up to 3.5 Gbytes. PDP-10 tapes racks up to 2.2 Gbytes. And bitsavers-mirror racks up to 126 Gbytes. Tim.

13 years, 3 months

8/L has been sold. Have ADM-3A for sale.

by charlesmorris＠direcway.com

The 8/L, ASR33, DF32 disk emulator project has been sold. Thanks for all your interest (and offers). Anyone who wants the DF32 emulator schematic and artwork, I can email you a copy. I hope someone can take my "first draft" and make a useful unit for those who are interested. I have a working ADM-3A that I may want to sell also. It has a homebrewed lower-case 2716 ROM (thanks Steve Loboyko for the font files). I installed the "optional" parts for current loop on the main PCB, and used it with the 8/L. The only thing that's missing is the little aluminum panel covering the dip switches. Any interest? Same deal as before, please email offers, "sealed bids". thanks Charles

13 years, 4 months

Altair 680 power supply...

by wh.sudbrink＠verizon.net

My Altair 680 has achieved the position of primary attention on my workbench. All of the ICs are socketed. Not having seen power in over 20 years, I did not trust the power supply as far as I could throw a bus. I pulled all of the ICs, attached dummy loads (automobile bulbs) and powered up. Sure enough, there was AC all over the place (where there should have been DC). I replaced all of the electrolytic caps and that got rid of the AC but some of the voltage levels are very wrong, at least as compared to what is written on the schematics. The worst offender is just off the "plus" side of the full wave bridge (BR-1). It should be nine volts but is actually at 11.5. This makes what should be the main five volt rail a little more than 9 volts... the far side of VR-1 (a 7805). The wave form coming off the transformer is really ugly not a smooth sine wave. I hate power supplies. I don't really understand, looking at the schematics, what this transformer should be doing. My guess is that it should be making a nice nine volt, 60 cycle AC sine wave with each of the two outputs 90 degrees out of sync? What could be wrong with a transformer that it would produce something like: __ / \ | \ / \_ / \ | / | / \_/ bent and very squared off at spots? My scope shows nice clean 120 coming into the transformer. How do I figure out a part number for a replacement transformer? Thanks!

13 years, 4 months

Oscilloscope Recommendation

by robert.jarratt＠ntlworld.com

I find myself in need of an oscilloscope to help me fix my PDP11 PSU (I am being ably assisted by a member of the list, so don't worry). As this is for occasional use only I can't justify spending a lot of money. From previous postings on the list I think I need a minimum spec of dual trace and 20MHz bandwidth. Does anyone have any recommendations for what to buy? I suspect it would be better to get a higher quality used one than a cheaper new one. Perhaps someone in the UK on this list has one they want to sell? Regards Rob

13 years, 5 months

Bad ebay experiance with ebay seller

by hp-fix＠xs4all.nl

I don't, I ordered the items at the end of January ... You can read the story in one of the earlier messages. > You can't blame him for customs. > ________________________________________ > > > Your item was processed through and left our SAN JOSE, CA 95101 facility > on > > April 18, 2011 at 11:27 pm. The item is currently in transit to the > destination. > > Information, if available, is updated periodically throughout the day. > Please > > check again later. > > > > If the items arrive in good order I'll of cause will send him the by > paypal refunded > > money. > > I'll keep you people posted. > > > > -Rik > > At last I recieved my items after they were held in customs .. > And of cause I payed them.. > > -Rik >

13 years, 5 months

Google Lisa List

by snhirsch＠gmail.com

Does anyone know who owns this list and how to get in touch with them? I joined last month, made about three totally innocuous postings and found myself banned at the next attempt to sign in. Google, in their infinite wisdom, gives you no means to find out if it's a mistake, appeal to the owner, or even get an explanation for why it's occurred! I sent a message to the posting address with no response. I had been given the name of "lowenddan at gmail.com" as list owner, but cannot get any response from that address either. Is there something I should know about becoming worthy of Lisa List membership? Perhaps a secret handshake I've overlooked? I contacted a couple of members privately, and both were utterly baffled as to what the motivation may have been. I'm still operating on the assumption that this is a software glitch or mistake. If I've been thrown off as a deliberate action, then I think it's common courtesy for the list owner to at least explain why this occurred. Steve --

13 years, 6 months

Vintage Portable Computing Suggestions?

by mark＠wickensonline.co.uk

Guys, I used a Cambridge Z88 for Retrochallenge last year (see http://www.retrochallenge.org for last competition) whilst on holiday. The summer challenge runs in the month of July - entries will be welcome anytime by email to me mark at wickensonline dot co dot uk. This year I'd like to use a different, portable computing device to document this year's summer challenge, and possibly include a little programming. My criteria are: * no larger than a Cambridge Z88. * daylight readable screen. * operates on batteries. * preferably with some kind of programming language/environment. I'd welcome suggestions from members of the list as to what I could take this year that would be fun to explore but also practical enough to use day to day to write text for the website. I will take a laptop for uploading text via wifi, so some sort of PC connectivity is a must (although this could be as simple as an RS232 cable). Many thanks, Mark

13 years, 6 months

Perkin Elmer 7300 Pro System Museum Quality!

by mail.list＠analog-and-digital-solutions.com

Here's one some of you might like. Perkin Elmer 7300 Pro System Museum Quality! http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2738081449 Current bid US $9.99

13 years, 6 months

What to do with Transputer Equipment?

by tshoppa＠wmata.com

> 10 GOTO 10 > Parallelize THAT. By the 1970's many timesharing and batch type compilers would kick out the embarrassingly useless programs without even trying (the environment well tested by millions of college student's programming attempts). I think the line between embarrassingly useless and embarrassingly parallel may not always be obvious. In many university-type batch processing systems, student programs that ran for more than 5 CPU seconds were summarily terminated as "obviously being stuck in some kind of infinite loop that the compiler can't catch yet". Just a few years later the same problems probably qualified for Grand Challenge grants :-) I remember when a very big fear of the US govt, was that the Japanese would wipe us out with Fifth Generation computers. (The WMD of the 80's) Boy, did that miss the mark. The Japanese came up with the Fuji Eagle (perhaps the most defining commodity-computing storage element ever) and today teraflop-class vector processors are in every fanboy's computer and they're called "graphics cards". Tim.

13 years, 6 months

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test-drb May 2011