test-drb

test-drb@ccmp.vtda.org

101090 discussions

by shadoooo＠gmail.com

Hello Rob, I'm quite sure that the tantalum explosion has nothing to do with the spin-up failure. Indeed the RD53 (Micropolis) is infamous for a problem in the head positioning shock absorber. The head positioning system is based on a voicecoil inserted in the magnetic field; the angle covered by the head arm is limited by two adjustable metal limits originally covered with rubber. At startup the mechanism is moved back and forth to check the two limits, and exactly at the ends a special magnetic pattern is recorded on the surface of the disks for calibration. Due to age, the rubber becomes goo, so the angle limits become wider, so during the calibration the head falls offer the calibration area and spin-up fails. The suggestion is to choose a clean room with few dust and a good lighting, carefully open the top cover of the disc, and remove the goo the more as possible using adsorbent sticks. Be sure not to touch the disc surface with the goo accidentally. Then try to insert some small pieces of paper over one limit (if I'm not wrong the failing is the left) in place of the missing rubber, and try the disc, and continue to add thickness until it works. Then you are sure about the right limit to move. Then remove the paper, loosen a little the screw, but just a little so the limit will not move unless pushed with some strength and a screwdriver. Then move a very small amount towards the center and try, then repeat trial and error until the disc starts. Then tight the screw and it is over. Close the disc and voila. Andrea

9 years, 6 months

Unibus disk controller with modern storage

by jnc＠mercury.lcs.mit.edu

> From: shadoooo > they can run linux for the software side Maybe it's just me, but running Linux on an interface card strike me as somewhat grotesque. It's bad enough running a far faster chip than the vintage CPU, but... a majorly complex operating system to boot? > I'm trying to figure if an hybrid QBUS / UNIBUS solution is possible. > Of course one have to switch some jumper to avoid conflicts Lots and lots and lots and lots of jumpers. The two buses are completely unlike, pinout-wise. And the UNIBUS board has to be a quad, and there are some QBUS chassis which only take duals... > What kind of bus transceivers did you used for the QSIC We used a mix of DS8641 quad transceivers (they're still available in reasonably good numbers for a reasonable price) and AM2908 octal latching transceivers with a tri-state output (to allow us to have a bidirectional internal bus for BDAL00-BDAL21 - we were trying to minimize the number of pins needed on the FPGA to interfaces to the QBUS). But we probably will use a different FPGA on the production boards, and all DS8641's. > you have to go from 5V open-drain logic to 3.3V logic? We do that with separate 74LVC7T245 level converter chips. Noel

9 years, 6 months

Weird List Post Error

by cctalk＠ibm51xx.net

Hmmm... I just sent a message to the list and got the following error: "Your message did not reach some or all of the intended recipients. Subject: RE: Archived viruses, was Re: Reasonable price for a complete SOL-20 system? Sent: 10/22/2016 10:30 AM The following recipient(s) cannot be reached: 'General Discussion: On-Topic and Off-Topic Posts' on 10/22/2016 10:30 AM 451 Requested action aborted: local error in processing" Resent the message again and it went through fine. Anyone else having trouble posting? -Ali

9 years, 6 months

Unibus disk controller with modern storage

by shadoooo＠gmail.com

Hello Dave, exactly! But in place of a plain FPGA, nowadays I would choose a FPGA-ARM board, for example the ZedBoard MicroZed or the Myirtech Z-turn, both of them have a Zynq onboard, and they can run linux for the software side and programmable logic for the interface side. Very nice and flexible. For the development, I'm trying to figure if an hybrid QBUS / UNIBUS solution is possible. Of course one have to switch some jumper to avoid conflicts, but hey, in the end you would have a true universal board. What kind of bus transceivers did you used for the QSIC, specially because you have to go from 5V open-drain logic to 3.3V logic? Thanks Andrea On 10/21/2016 07:00 PM, cctalk-request at classiccmp.org wrote: > You mean, perhaps, something like this? > > http://pdp10.froghouse.org/qsic/html/overview.html

9 years, 6 months

MOTD: It is amazing how many ways you can make mistakes with 32-bit instructions

by pbirkel＠gmail.com

Published in the National Computer Conference, 1976. Full quote: "He bought an RPC-4000 "at a graveyard-type disposal sale," and later noted, "My RPC is working but I can't get an assembly program more than two-thirds loaded. This produces lots of messages telling me my programs are bad" I suspect some memory aberrations, but the memory print routine won't print either. So I have been trying to write a simpler routine of my own in machine language. That is a drag. It is amazing how many ways you can make mistakes with 32-bit instructions." " Also memorable: "An Indiana hobbyist bought a Univac 0 File Computer as scrap, with arithmetic unit, program-control unit, 90-column reader/punch, sort-collate unit, tape-drive program controller, and six magnetic-tape units. The new owner says, "I had figured to use the outside winter air to get it turned on and see what I've got, and just close down in summer. As to space, not too bad: only about 400 or 500 square feet, pretty compact. I'm presently having 220 V installed to begin to turn on some of it." And *we* think that we have it tough :->. From: https://www.computer.org/csdl/proceedings/afips/1976/5084/00/50840235.pdf -----

9 years, 6 months

Archived viruses, was Re: Reasonable price for a complete SOL-20 system?

by billdegnan＠gmail.com

> > John McAfee predicted that 5 million computers would be wiped out. > The press were called in. > > On March 6, there were apparently DOZENS of drives wiped. Few, if any records kept to verify numbers. > McAfee, as expected, took full credit, and declared that the REASON why it was dozens, instead of millions, was because his warnings were heeded. > > Six months later, when he took his company public, he raised 42 million dollars. > > He is currently a fugitive as the "prime suspect" in the murder of his neighbor in Belize (apparently NOT virus related) > > Side note...maybe 6 or 12 months before the big virus scare I called McAfee on the phone and spoke with him about a virus I found on a GRID laptop that I found was copied to 4000 similar machines out in the field where I wokred. He emailed me his latest test iteration of his software, a copy on a scratch disk. It was a very early version. I had no idea of course of his future, but I was impressed with his software because it was light, no install disks and he knew his stuff. We were talking about how to inject his antivirus prpgram into a program I wrote to update laptops remotely by modem, and how we could send virus updates via this process. It was getting impractical to keep sending me disks and we needed a better way. You could not buy his software Viruses were starting to get more numerous. I don't know if he had just started his company, it was not public or anything yet. In fact I got his number inmformally from a manager at a company called Sales Tchnologies out of Atlanta, I w as working with their sales tracking program they were already using my "mass update" system to manage their software and data updates. That's where the virus came from. Fun times all MS DOS based, btrieve database, Sprint Internet exchange for free phine calls inbound >from anywhehre in the USA... I also remember building and compiling Sales Tech software version updates on a xerox workstation. When I left they offered me the Xerox but I remember thinking what would I ever do with *that* old piece of junk? "Well Bill you're the only one who knows how to use it so we will just throw it away then, are you sure".."yah, my apartment is too small...." At least that's how I remember it. Bill

9 years, 6 months

Archived viruses, was Re: Reasonable price for a complete SOL-20 system?

by billdegnan＠gmail.com

On Oct 21, 2016 8:30 PM, "Steven M Jones" <classiccmp at crash.com> wrote: > > On 10/21/2016 14:15, william degnan wrote: > > Any disk or archive you come upon from the early 90's should be scanned for > > viruses before use on a vintage machine. USe a modern PC as it's no biggie > > to clean old viruses that way. Scan before you use on an older machine, > > scan inside of ZIP files not just the zip itself. There were three viruses > > that I found years ago on the most-often seen Maslin archive set. Old > > stuff that's not an issue for modern machines. > > I didn't think modern A/V products included complete historical sets of > signatures. I'm sure they can deal with ancient, simple bootloader > infections and such, but at some point I'd be concerned there's a gap > where something might be too new to be detected by the simplest > heuristics, but too old for a more sophisticated signature to be in your > common modern products. > > But this isn't something I've had to deal with. Is this an imagined > problem, or has somebody run into this? > > Thx, > --S. > Stoned Monk is still detectable by modern anti virus software, 25 or whatever years later, at least last time I tested using a win 7 machine. So, that was maybe 4 or 5 years ago.

9 years, 6 months

HP 7945 disk format

by aek＠bitsavers.org

for anyone wanting to try David's MFM emulator in an HP MFM 7945 disk box, here is the format, determined from reading a Vertex V170 drive from one --sectors 32,0 --heads 7 --cylinders 987 --header_crc 0xffff,0x1021,16,0 --data_crc 0xffffffff,0x140a0445,32,5 --format WD_1006 --sector_length 256 The 7945 is notoriously flaky because of the Vertex drives.

9 years, 6 months

PDP-11 RL02 disk emulation

by scott.l.baker＠gmail.com

Hi, The author of this project http://www.pdp11gy.com <http://www.pdp11gy.com/doneE.html> built a wire-wrapped board to interface an RL02 controller (RL11, RLV21, or RL8A) and an FPGA development board (which does all the heavy lifting for the disk emulation). I decided to build one of these emulators and to design a printed circuit board rather than using wire wrap. The schematics and layout of my RL02 interface board can be found here: http://sierracircuitdesign.ddns.net/temp/RL02 I made changes to the original design (e.g. I used different driver and receiver chips) but I think it should be plug compatible with the original wire-wrapped design. Feedback on this project is most welcome. Regards, Scott

9 years, 6 months

Burroughs B5000 emulator

by kspt.tor＠gmail.com

On 21 October 2016 at 16:37, Liam Proven <lproven at gmail.com> wrote: > A friend of mine is working on an emulator for this Burroughs Large > Systems beast. [..] > I have suggested to him that it might be easier to work under an > existing mini/mainframe emulator, such as SimH or maybe even > MESS/MAME, but he is highly resistant to this idea, for reasons I do > not really understand. > > I'm interested in opinions: do folk think that it would help, or not? I fully understand. Not everything is easily tweaked to fit into those frameworks. When I wrote my two minicomputer emulators I couldn't see how on earth I could get that working inside simh without increasing the work needed ten or fifty times. There wasn't anything there that would help me for what I had in mind.

9 years, 6 months

Jump to page:

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb