test-drb May 2016

test-drb@ccmp.vtda.org

202 participants
259 discussions

by jnc＠mercury.lcs.mit.edu

> From: Mattis Lind > I also have a YF card. ... I could access the contents but it didn't > run very well. So either the CPU is still bad or the PROM contents are > bad. Could you please direct me to your YF dumps so I could compare? They are on my "Miscellaneous Digital Equipment Corporation PDP-11 Information" page: http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/PDP-11_Stuff.html in the "ROM Dumps" section. > If you also have done a disassembly that would be very interesting. I haven't completely disassembled the -YF version, but the -YA is almost all done, so it should help. Let me know if you need to have the -YF fully disassmbled & commented, and I'll hop to it. Noel

9 years

PDP11 M9301-Yx ROM dumps

by jnc＠mercury.lcs.mit.edu

OK, so we already had a dump of the M9301-YA ROMs, but were (apparently) missing the others? So I fnally got one of my UNIBUS 11's running, and whipped up a small program to dump the ROM contents, and now have the -YB, -YF and -YH ROMs dumped. I'm in the process of disassembling them now. (If anyone needs the contents in binary format, to blow new ROMs, let me know, and I can probably produce them if you give me the details on the format you need the data in.) Does anyone have any of the others - YC, YD, YE and YJ? If you're not up to dumping them, I can send you my small program (currently in .LDA format, but I can convert it to a script - it is not very long at all - for the console emulator in the M9301 series), which will do it - it produces packed octal output, 8 words/line, so a very small output. Noel

9 years

PDP-11

by jnc＠mercury.lcs.mit.edu

> From: Dave Wade > I have recently a PDP-11 which apparently came from a VAX console. If that's really where it came from, it's a QBUS 11/03. (And IIRC only the 780 had a PDP-11 console, although I'm not a VAX expert.) > It looks to me like there are two CPU's in there Well, as Bill said, send us the 'M-numbers' (on the board handles), and we'll tell you what you've got - but multi-CPU PDP11's basically don't exist (with some rare exceptions), and certainly not in a VAX console. So I'm not sure what you have there. > and Bus Terminator Actually, that's the 'QBUS out' connector card; the way the PDP-11 runs the VAX is that there's a card in the 780 CPU which is on the QBUS (there are cables that run from the QBUS out to that card), and it allows the -11 to totally control the 780 CPU. > I have done lots of searching and there doesn't seem to be a simple > list of what can run on it Well, nothing that needs memory management - at least, as it sits. You could swap out the CPU card for an 11/23 or 11/73, then you could run an OS that needs memory management (Unix, or one of the DEC OS's that needs it - I know nothing of the DEC OS's for the -11, someone else here will, though). And your backplane is probably so-called Q18, limited to 256KB of memory, but that's easy to upgrade. Noel

9 years

Myths about Lisp [was RE: strangest systems I've sent email from]

by RichA＠LivingComputerMuseum.org

From: ben Sent: Wednesday, May 11, 2016 5:42 PM > On 5/11/2016 5:54 PM, Toby Thain wrote: >> On 2016-05-11 7:43 PM, Liam Proven wrote: >>> If we'd had 4 decades of effort aimed at fast Lisp Machines, I think >>> we'd have them. >> Compiled Lisp, even on generic hardware, is fast. Fast enough, in fact, >> that it obviated Symbolics. (More in Richard P. Gabriel's history of >> Lucid.) See also: The newly open sourced Chez Scheme. > But List still sequential processing as far as I can see? How do you > speed that up? This is another of the long-standing myths perpetuated by people who know nothing about the language. It has literally been decades since lists were the only data structure available in Lisp. If you need non-sequential access to process data, arrays are the ticket, or hashes. Choose the best data structure for to problem at hand. (Similarly, data types other than atoms have been around since the very earliest LISP. They just weren't sexy, and didn't get a lot of press since they weren't novel and difficult to understand. Math code from the MACLISP compiler was better than that generated by the F40 FORTRAN compiler.) >> The myths around garbage collection are also thick, but gc doesn't >> impede efficiency except under conditions of insufficient headroom (long >> documented by research old and new). > Well GC is every Tuesday here. :) You joke, but in one of the visionary papers on GC from the early 70s, a tongue-in-cheek scenario was proposed in which GC was done by a portable system which had sufficient memory would visit large facilities to do background GC for them on, say, a monthly basis. Rich Rich Alderson Vintage Computing Sr. Systems Engineer Living Computer Museum 2245 1st Avenue S Seattle, WA 98134 mailto:RichA at LivingComputerMuseum.org http://www.LivingComputerMuseum.org/

9 years

"Retro Repair" key electronics skills?

by ard＠p850ug1.demon.co.uk

> > My father is a civil engineer. When I was a little > kid, he was in the US Air Force. We would frequently > go to the runway snack bar, get ice cream and watch > the B-52s do "touch-and-go" landing practice. The > plane's wings would "flap". It raised the hair on > the back of my neck. My dad explained that, if they > didn't flex, the wings would break off. After a > while, I understood, intellectually. It still "gave > me the willies". Later I had a similar experience > when I was with him in a tall building and realized > that it was "waving in the wind". Same thing, if it > didn't flex, it would fall. That reminds me of the following joke : There is an airline passenger. During some particularly turbulent conditions he looks out the window and sees the plane's wings flexing. He looks very worried. The flight attendant comes over to him and tries to comfort him by saying 'Our pilots are fully trained to fly in conditions like this. It's only turbulence, it's quite normal' He replies 'You don't undertand. I work for Boeing. I am one of the men who designed this aircraft. The wings are not supposed to flex like that.' > > The other is that, as I said before, any ground > > connection has impedance (it's the inductance that > > is troublesome normally) so that points (say IC pins) > > that are shown as grounded may actually have a > > voltage difference between them. > > If I think about it too much, this gives me the > willies, the same way. It's a very real problem, it's the main reason for decoupling capacitors which provide a local source of power with a low impedance connection (as they are so close to the IC). That's why I said that most times the interconnections are the hard part of a digital circuit. -tony

9 years

3D Printing cases and SGI "skins"

by swiftgriggs＠gmail.com

Has anyone used a 3D printer to make a case for their old machine ? I've started drafting an SGI Indy "skin" in Sketch, but it's just a box right now, nothing cool. I've noticed and been somewhat inspired by these: I think this one is very clever. The guy used 3D printed parts just to sort of "glue" the heatsink and lucite/glass together. It looks great. http://technabob.com/blog/2012/12/27/diy-silent-computer/ This guy made one for an Intel NUC: http://tinyurl.com/k9xpb9s This person used plexiglass to overcome print size issues I'm guessing: http://www.ocaholic.ch/modules/news/article.php?storyid=12671 Here is one for a Pi that looks like a NES http://technabob.com/blog/2014/04/27/3d-printed-raspberry-pi-nes-case/ This one is also for a Pi, but is a bit like a laptop, too: http://tinyurl.com/z8rgrmd A C64 custom job: https://3dprint.com/39764/3d-print-commodore-case/ Obviously, this kind of thing would be great for SGIs, which are mostly made to accomidate plastic covers on metal skids (ie.. "skins"). -Swift

9 years

PDP-11

by jnc＠mercury.lcs.mit.edu

> From: Dave Wade > Small card, looks like it fits deep in bus. If it is a QBUS grant continuity card, it will have two looped-back pin pairs (the QBUS has two grant lines - DMA and interrupt) on the back-side, with a blank pin between them. (AM2-AN2 and AR2-AS2, to be exact.) > Any clues on where I can find pin-outs for making a cable. All the DEC 40-pin serial line headers have the same pintout, AFAIK. So you can use any of the manuals for the DL11, e.g. EK-DL11-OP-001, available widely, e.g.: http://vaxhaven.com/images/4/42/EK-DL11-OP-001.pdf which uses that same pinout, and has it in great detail, for making a cable. Those directions produce at DTE cable - if you want to produce a DCE (suitable for plugging into another computer), you need to reverse RD and TD, etc. Noel

9 years

PDP-8/A 128K memory - M8417 or M8418?

by j＠ckrubin.us

I've been looking for a 128K MOS memory board for my PDP-8/A for a while. I finally got one, but it turned out to be an M8418. The docs I've seen (bitsavers EK-MS8CD-TM-001, 1980 + printsets) talk about an M8417 with 4k DRAM chips (MS8-C) and an M8417 with 16k DRAM chips (MS8-D), but apparently at some point the 16k versions became known as the M8418. The card I received has 96 Fujitsu MB8116E 16k DRAMs, arranged in two 8 x 12 chip arrays. The actual circuit board says PDP MOS MEMORY - M8417 - 50 12701B on the back but the metal card ejector edge is stamped M8418 JC. Chip dates on the board put it at 1980 production. None of my literature has the M8418 p/n but most of it may be too old. The M8418 part number (with JC suffix to indicate Fujitsu RAM) does show up in the 1988 Options Module List. I know several list members have similar boards. How are they marked? Can anyone point to more info on the M8418? Thanks, Jack

9 years

Interact Model One Software

by bradhodge75＠gmail.com

Hi guys, I scored a cheap Interact Model One (original with chiclet keys). It's an interesting piece - much larger than photos suggest. It appears to be somewhat functional (comes up to the press L to load tape screen), however I lack any tapes to load with it. I've not found any archives of tapes for this thing anywhere (I guess being an oddball computer like it is, not much demand). Wondered if anyone out there had one of these and if software was out there? Brad

9 years

Bags for RK05 disk cartridges

by j＠ckrubin.us

Now that I've cleaned a stack of RK05 DECpacks, I want to keep them clean. Ideally, I'd like to find Ziploc-style poly bags like the DEC originals with the warning about dirt on the heads (the famous hair/head picture). I haven't been able to find a match for the original (roughly 16.5" square) but I have a sample of U-Line S-14411, a 6 mil reclosable bag that measures 16 x18. It's just slightly snugger than the original but seems to do the job. Does anyone have any other suggestions? Thanks, Jack

9 years

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test-drb May 2016