test-drb September 2016

test-drb@ccmp.vtda.org

162 participants
227 discussions

by emu＠e-bbes.com

Anybody has a spare one, to sell? With all the discussions about the P350/P380, I went to my storage, and found two p350s without power supplies :( Cheers

8 years, 3 months

RK05 packs

by jnc＠mercury.lcs.mit.edu

> From: Ethan Dicks > 12-sector packs are abundant compared to 16-sector packs Really? Most of the RK05 packs I've seen for sale on eBay in the last couple of years have been 16-sector - so I naturally assumed they were more common. Well, I guess that explains why my offer to trade drew such a response! :-) Noel

8 years, 3 months

SWTPC 6800 weirdness

by vintagecomputer＠bettercomputing.net

My 6800 has been mostly working, but it seems to be occasionally flaking out. I don't know why. Sometimes you go to power it up, and there's no response on terminal side. The 'fix' is sometimes to wiggle the memory/CPU boards and then for some reason it's fine(ish). There are five cards installed right now - the MP-A, MP-S, a heavily modified MP-M board (with rams piggybacked on all the original RAM chips) and then two Digital Research 16k boards. The system was modified for Flex 2.0 Today it flaked again and would not come back up, so I pulled the MP-M board and the MP-A board and swapped slots. It came up, but memory at $0100 was missing. I tried powering up, swapping slots, etc.. same deal. Then I left the machine for an hour, powered up again.. boom.. now $0100 is back. I don't fully understand the addressing system but if that MP-M is configured as $A000 would that cover $0100 as well? I've tried changing the jumpers on each of the DR 16k board to cover $A000.. but the machine will not boot. I will only work with either the MP-M alone or those 16k cards with it configured to other spaces. In other words, the machine does not accept any other card configured for $A000. I'm wondering if anyone has any suggestions on how I might nail this down. I'm thinking some of the RAMs on that MP-M are flaky, but it would be a *nightmare* to try and diagnose it, with all the RAMs piggybacked, all the little jumper wires, and everything soldered. I'd prefer to bypass it and either use my other, less modified MP-M or just the DR boards, which are socketed. If any of you have suggestions on how I might take this MP-M out of the equation that would be awesome! Brad

8 years, 3 months

UNIBUS M9312 ROM type identification

by jplist2008＠kiwigeek.com

Greetings; My googlefu is failing me and I was wondering if someone might be able to help me identify one of the boot ROMs present in an M9312 bootstrap/term board. The board has three ROMs, an RX01 (042130), an RX02 (042131) and then a mystery code - 043127. The M9312 ROM identification table does not list this ROM code - I suspect it _might_ be for a DSD combined 8" drive and Winchester disk box, but I'm under the impression this would appear as a DU device, and attempting to boot from DU gets an ILL CMD, suggesting otherwise. I tried all of the other possible mnemonics listed in the M9312 manual, so it doesn't appear to piggy-backing on any of those either. My thanks; - JP

8 years, 3 months

Odd memory error in PDP-11/04

by jnc＠mercury.lcs.mit.edu

> From: Ethan Dicks > What's happening now . is when I change one location .. it > echoes across multiple locations... > ... > 1) Depositing any value is echoed 000020 later. > ... > Does this sound like a dodgy CPU, dodgy RAM or both? It could be either. One possible cause of the symptoms you're seeing is that address line A04 on the bus is being held to one value (high or low) by something on the bus, so that whether the CPU tries to set it to 0 or 1, it has no effect. Also, of course, there could be some fault in the CPU, so that when it tries to do something with address 0, it gets 020 (or vice versa). And similarly for the memory. I'd try to write a small (two instruction) loop that sets that address line high/low (e.g.: 5037 CLR @#1020 1020 775 BR .-4 and look and see if that address bit is flickering on/off on the UA11 (it will be on, but dully; constant assertion is bright on, constant de-assertion is full off). If so, the problem is almost certainly in the memory; if not, it could be either. > 2) Setting D10 in location 000000 results in D10 set in all the > locations Sorry, didn't follow that? Did you mean that if you store 02000 in location 0, all other locations now report the 02000 bit set? Noel

8 years, 3 months

vt100 terminfo with padding for an actual vt100?

by fritzm＠fritzm.org

Hi all ? I?m trying to run a real-deal vt100 on a serial port connected to Linux (Xubunto 16.04). I?ve got this working *pretty* well, but it looks like the padding values in the default vt100 terminfo entry are not quite correct ? when running the vt100 at 9600 I still get occasional garbage characters on the screen, and 19200 is a hopeless mess. I did figure out that if the terminfo contains ?xon?, the non-mandatory padding values in the terminfo are disregarded. Removing this, then disabling xon/xoff on both the vt100 and the tty device actually produces *better* results ? apparently the turnaround on xon/xoff isn?t quite fast enough to keep the terminal from being swamped at higher baud rates, and padding actually works better. But tracking down the source for the default vt100 entry turned up a comment that admits that the padding values there are a total guess. :-( So, before I go diving too much further into the terminfo-tweaking-samp, I thought I?d ask if anybody has a good vt100 entry already on hand? (I?d take one for the VT52 as well!) thanks much, ?FritzM.

8 years, 3 months

11/04

by useddec＠gmail.com

Hi Ethan, If you are going to VCF and I go, I'll Try to throw a MS11-JP in the van for you. It's yours for bugging the guy with the H960s one more time. That should save you some chip chasing time. Thanks, Paul

8 years, 3 months

More mystery recycler boards - DEC, Fujitsu(??), Cipher, Emulex

by jnc＠mercury.lcs.mit.edu

> From: Jules Richardson > M8190-AE ; 11/83 CPU > M8190-AB ; 11/83 CPU (or /73??) w/FPU As far as I know, all the M8190's are _basically_ the same: they are the KDJ11-B CPU, which support the PMI memory bus, can operate with a KTJ11-B to provide a UNIBUS, etc. They are the CPU in an 11/83 (with QBUS only backplane) and the 11/84 (with QBUS/UNIBUS backplane). The various models of the M8190 vary in details (e.g. although all have a socket for the FPJ11 floating point accelerator chip, the earlier ones don't work properly with it), including the clock speed (15/18 MHz, etc). The 11/73 uses the KDJ11-A M8192, a completely differente card. Noel

8 years, 3 months

Y Combinator is restoring one of Alan Kay's Xerox Alto machines

by curiousmarc3＠gmail.com

Ken's in-depth blog post to go with the previous video http://www.righto.com/2016/07/restoring-y-combinators-xerox-alto-day_11.html > On Jul 5, 2016, at 2:46 PM, Curious Marc <curiousmarc3 at gmail.com> wrote: > > Video from yesterday?s work on the Diablo cartridge disc: > https://youtu.be/PR5LkQugBE0 > Should be up in a few minutes. > We were tickled pink to have official representation from PARC (former Xerox Parc) at the session. > Marc > > Ken?s new post on the monitor repair to go with my previous video. > http://www.righto.com/2016/07/restoring-y-combinators-xerox-alto-day.html > Al Kossow got us a new CRT tube, so we are probably going to try that this week-end. > Marc > > > Latest entry from Ken Shirriff, trying out BCPL (ancestor of C). On the emulator, not yet on the real machine: > http://www.righto.com/2016/06/hello-world-in-bcpl-language-on-xerox.html > > Marc > > There are only two entries right now: > http://www.righto.com/2016/06/y-combinators-xerox-alto-restoring.html > http://www.righto.com/2016/06/restoring-y-combinators-xerox-alto-day.html > Marc > >

8 years, 3 months

The huge lot that had the NIB 8" floppies is now on ebay

by jnc＠mercury.lcs.mit.edu

> From: Jason Howe > Some pretty interested stuff comes up on ebay occasionally which I > might not have seen otherswise. Exactamundo. > when folks just dump an ebay item number rather than a full link, those > posts should die Why? It's a tiny bit more work to use them (prepend the number with the string "http://www.ebay.com/itm/", and away you go), so one can't just click and go, but are people really that unwilling to go to the slightest effort? Noel

8 years, 3 months

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test-drb September 2016