test-drb June 2019

test-drb@ccmp.vtda.org

151 participants
141 discussions

unix developed on 11/20 with 20 on panel or machine that just said pdp/11?

by wkt＠tuhs.org

Paul Koning wrote: >> The 1971 Unix Programmer's Manual mentions their 11/20 had 24 KB >> (surely KW?) memory rather than 28KW. > I would assume kW. In the PDP11 world we didn't normally speak of > bytes or kbytes, certainly not for memory and often not elsewhere either. The PDP-11 Unix source: https://github.com/DoctorWkt/unix-jun72/blob/master/pages/e00-01 says: orig = 0 core = orig+40000 / specifies beginning of user's core ecore = core+20000 / specifies end of user's core (4096 words) So: 40000= 16KB for the kernel, 20000= 8KB for the user program. Cheers, Warren

5 years, 6 months

unix developed on 11/20 with 20 on panel or machine that just said pdp/11?

by wkt＠tuhs.org

According to this page that Dennis Ritchie wrote, the original PDP-11 they used was indeed an 11/20 but it was before there were PDP-11 model numbers: https://www.bell-labs.com/usr/dmr/www/picture.html And, of course, the PDP-7 Unix development came before the PDP-11 version :) Cheers, Warren

5 years, 6 months

unix developed on 11/20 with 20 on panel or machine that just said pdp/11?

by wkt＠tuhs.org

Steve Malikoff wrote: > It states that their 11/20 had a KS-11 memory management unit, was that > mandatory for running v1 Unix on an 11/20? I case-insensitively grepped for 'ks.*11' in the Github repository here: https://github.com/DoctorWkt/unix-jun72 and I didn't see a mention. > The 1971 Unix Programmer's Manual mentions their > 11/20 had 24 KB (surely KW?) memory rather than 28KW. 28KB is right. The simh.cfg from the repo says: set cpu 11/20 set cpu 32K Cheers, Warren

5 years, 6 months

Teac FD55-GF drives wanted for experiments in reading Twiggy floppies

by spacewar＠gmail.com

Is anyone willing to sell me a few Teac FD55-GF or -GFR floppy drives (PC 5.25-in high density) for less than eBay prices? I want to experiment with modifying them to read Apple Twiggy diskettes, primarily by adding a microstepping driver for the head positioning. I specifically want Teac drives because there are reasonably good service manuals on them, and I don't want to deal with multiple brands of drives. The handwritten labels on the Twiggy diskettes I recently acquired make it appear that they were used for prerelease Lisa development. I will be getting more of them in a few weeks, from the same source.

5 years, 6 months

Wanting to get my first classic computer

by raywjewhurst＠gmail.com

Hello all, I have been a student of computer history for years but have only learned how to use classic machines vicariously through emulation. I would really like to get my own classic computer but I don't know where to begin. For one, I am on a very limited income and two I don't have a lot of space and finally I don't have much knowledge on the finer points of the older hardware i.e. terminals networking, etc. I would really like a Vaxstation but I have also considered a '90s workstation such as an SGI Indy or a SparcStation. I am pretty fluent in both VMS and Unix so any of those would work. So where do I look besides e-Bay? I see some available here but none near me. I'm in the Detroit area. Any advice would be appreciated. I do know that I do now want a Mac or old PC. I would like something more exotic. (Although it might me neat to own a Rainbow.) Thanks Ray

5 years, 6 months

unix developed on 11/20 with 20 on panel or machine that just said pdp/11?

by couryhouse＠aol.com

unix developed on 11/20 with 20 on panel or machine that just said pdp/11? Help - have a? nice? looking? 11/20? plus? a? weird analog? computer and? a? Nike guidance? gyro platform? for? AJAX (? 2? gyros loose? need? prints? to? rewire? correctly)? ? ? in? trade? for? and? extra? ribbon Mike? we? had. so anyway today's? questions -? bell labs? UNIX? machine? ?says? 11? or? 11/20 -anyone have schematics or wiring chart? for NIKE AJAX? Gyro Plantform? Drop offlist? as? not? to? clutter? things thanks? Ed#

5 years, 6 months

Dumping MC6801 ROM contents.

by mattislind＠gmail.com

I have been asked to dump the ROM contents out of the MC6801 in the Ericsson PC keyboard to get the MAME emulation fully working. The guy that is doing the emulation says this is the only thing missing and would be nice if I could help him getting it finalized. It is supposed to be quite easy. Put the MC6801 in test mode 0 and provide RESET vectors for an external EPROM that has a program that dumps the contents. Maybe in Intel HEX over the serial port. Should be quite straight forward. But I have thousands of other things to deal with so if someone already made such a small program I gladly use it instead of making my own. Even though I done some 6800 and 6809 assembler once upon a time, it was 30 years ago, so I imagine it will take some time to get it working. Is there anyone that already done this? /Mattis

5 years, 6 months

PDP 11/15

by useddec＠gmail.com

I bought a large package of DEC gear last year and it came with a PDP 11/15. I have no need for this classic, and put it on the list. A few people responded, but because of my problems, I never followed up with them. For those who responded, I apologize for dropping the ball. If anyone is interested in it, please contact me off list. BTW, I have started on pulling a few things out of the warehouse. Thanks, Paul

5 years, 6 months

vaxstation ii machine check & diags efficacy

by joezatarski＠gmail.com

> It's a VAXstation II/GPX. I'm trying to install VMS 5.5 (from CD if it matters; there is a CMD CQD-200 or -220 as the only storage controller) and routinely getting machine check exceptions. > > Standalone backup always boots. Sometimes I get an exception the moment I hit <enter> on a restore; sometimes in the middle of the restore, sometimes it runs to successful completion. > > VMS never boots. Sometimes I get as far as the date prompt (I took out the battery), sometimes it gets a little farther, frequently it's before anything appears on the console at all. > > The exceptions booting VMS occur the same if I attach another disk with VMS 5.5 already installed; if I replace the KA630 and M7609 with a KA655 and M7622, it all seems to run fine. > > The KA630 power-on diagnostics all pass, but... it smells like a memory fault to me. What are the odds there could be a memory fault that isn't caught by the diags? > > ok > bear. > > -- > until further notice Well, if the KA630 diagnostics are anything like the KA650 diagnostics, the power on self test is not too thorough as I learned. I found 10 bad DRAMs on a KA650, the POST only found 2 of them. The rest I had to test by running tests from the monitor with tighter parameters. You should get into the console monitor on the KA630 and see if you can get a list of tests to be run with the TEST command. Sometimes they have parameters, and you can specify more thorough tests to be run. Keep in mind, they may take considerably longer to run than the POST does. I'm speaking from KA650 experience here, but I was able to run the MEM_Data test on all of memory with an address increment of 1. It took about 4 or 5 hours to complete I think, for 8MB of RAM.

5 years, 6 months

Apollo Computer Article

by brain＠jbrain.com

Probably too light for folks in here, but maybe some will find some interest (apologies if https://www.fastcompany.com/90362562/this-computer-changed-world-youve-neve… -- Jim Brain brain at jbrain.com www.jbrain.com

5 years, 6 months

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test-drb June 2019