test-drb July 2014

test-drb@ccmp.vtda.org

181 participants
190 discussions

curious to know if anyone knows what computer this is

by lori.emerson＠gmail.com

Hi all, you might have seen this going around online today - but I can't for the life of me figure out what kind of computer Mickey is posing with. Anyone know? http://parksandresorts.wdpromedia.com/media/disneyparks/blog/wp-content/upl… Lori -- Lori Emerson Assistant Professor | Director, Media Archaeology Lab Department of English, University of Colorado at Boulder Hellems 101, 226 UCB, Boulder, CO 80309-0226 loriemerson.net | mediaarchaeologylab.com

10 years, 5 months

IEEE commemorates Kildall and CP/M

by joachim.thiemann＠gmail.com

I figure this article in the IEEE Institute Online might be of interest to others: http://theinstitute.ieee.org/technology-focus/technology-history/groundbrea… Basically, a plaque was unveiled in Pacific Grove to honour Gary Kildall marking CP/M as a milestone in the development of computing. Cheers, Joachim. -- Joachim Thiemann :: http://jthiem.bitbucket.org :: http://signalsprocessed.blogspot.com

10 years, 5 months

TI Silent 700 model 725 service/maint manual?

by chrise＠pobox.com

Is anyone aware of the existance of a maintanance / service manual for the old TI "portable" data terminal, model 725? Note that is is one of the very early (and very large) thermal printing terminals from TI, http://terminals.classiccmp.org/wiki/index.php/File:Silent700_725ad.jpg I have several here that I am trying to keep running but have never had technical information that would include schematics or other parts information. Chris -- Chris Elmquist

10 years, 5 months

IBM 5170 AT 286 bios: how to add a new HARD disk

by fritz_chwolka＠t-online.de

Am 19.07.2014 23:08, schrieb Enrico Lazzerini: > I managed to find a bios for an IBM 5170 AT 286 Type1 Mainboard. It is > here: 30aprile1989 (list here: > http://ibm-pc.org/firmware/ibm/5170/5170.htm) > In practice I have manually added the number of cylinders, heads, and sect > / trk that allow the machine to recognise a disk IBM 250MB. At this point > regularly boots DOS. > But I wish to program these data permanently in the bios. Does anyone know > what program to use and give me the procedure? I tried with BIOSUTL, but > the new EPROM do not boot the machine. > With BIOSUTL i made what follow: read actual BIOS, you can add new disk > geometry parameters at free 47 position, then you have to recalculate bios > checsum, then BIOSUTIL devides BIOS into EVEN and ODD file so i can finally > program them into two 27256 150nS eprom. > Thank you > Enrico > > Hi.. the biosutil maybe one way. The version I use told me: Biosutil V1.1 InfoMatrix Bios utilities for the AT BIOS. Brad Gibson Copyright (C) 1990 by Secret Software and I believe there's no other version. *----------------------------------------* Other idea It maybee better to add a enhanced bios to your PC. There is the xtide bios at https://code.google.com/p/xtideuniversalbios/ The xtide bios works on most xt/at. You can easily ad an enhanced bios if you have an free rom place in a network card like a ISA 3com etherlink. As Im from germany and my english isn't as good as it should be here is an explanation from http://flint.cs.yale.edu/feng/research/BIOS/BIOS-report.pdf The IBM BIOS gains much of its versatility by being an extendable BIOS. That is, the full extent of the BIOS is not cast forever in the silicon of the single PROM chip holding the firmware. The IBM BIOS can accept additional code as its own into one integrated whole. Hence additional PROM chips containing BIOS routines can be added to the PC. The BIOS will incorporate these new routines. The key for making BIOS extendable is a Firmware routine that enables the BIOS to look for add-in code. During the boot up, BIOS code reads through the address range that is set aside for firmware looking for codes stored on add-in boards. If a valid section of code is found, the instructions are added to the BIOS repertory. For instance a new interrupt routine can be added or the functions of existing routines can be changed. During POST after interrupt vectors have been loaded into RAM, the resident BIOS code instructs the computer to check its ROM memory for the occurrence of the special preamble bytes, that mark the beginning of add-in BIOS routines. The BIOS searches for these preamble bytes in the absolute address range 0C8000 - 0F4000. Here the XTIDE BIOS is found and added so you can use it. Greetings fritz

10 years, 5 months

DEC Y and W series boards

by useddec＠gmail.com

Anybody out there older than me whose memory works better than mine or younger but smart enough to figure out what these were used in? More digging... Any interest? Y048 Bell tape controller with cable Y051 Bell Binary to ASCII converter Y064 Card reader Y185 Stare 3 ??? Y197 DMA interface W742 Universal digital input W743 Universal digital input W950 Wire wrap module- unused W968 Collage mounting board- unused Thanks, Paul

10 years, 5 months

PDP-8 VT8-E

by rick＠rickmurphy.net

At 12:00 AM 7/21/2014, Eric Smith wrote: >On Sun, Jul 20, 2014 at 8:10 PM, Rick Murphy <rick at rickmurphy.net> wrote: > > I don't know anyting about a PDP-14, > >The machine is question is a VT14, not a PDP-14. The VT14 is a >specialized terminal used to develop ladder logic programs for a >PDP-14. > > > but it it used a VT8-E, > >It didn't. Full circle. There seem to be two sets of assertions here. One that a VT14 used the VT8-E board set, and another that it used a different set for video. You're asserting that it's not a VT8-E, which means that many of my assumptions were wrong. In one of it's modes, which would allow it to be a good display device, the VT8-E uses DMA from main memory to drive a bitmap display. That memory has to be on the Omnibus, and has to be read/write to be of any value. That causes the following assumption: > > it had to be an Omnibus machine with Omnibus memory, > >It was. > > > so it could easily be turned into a PDP-8/E > >That doesn't necessarily follow, any more than it would follow that >because some sort of embedded device contains a Z80 CPU chip, it can >easily be turned into a CP/M system. You have a KK8-E cpu and the standard Omnibus which can accept a range of peripherals. You can't usually plug extra hardware into an embedded system. > > with the right CPU card set. > >It had a KK8-E CPU card set. To get it to run general-purpose PDP-8 >software, you're going to have to replace the memory, as the MR8-F >isn't too useful for that. I see. Perhaps it's the case that the VT14 doesn't have Omnibus RAM, and only has a MR8-F which the KK8-E CPU uses to run the code that manages the display. This is the first I've heard of the MR8-F, which apparently has onboard RAM to provide the read/write memory needed. (The older Ombibus ROM devices shadowed core.) >The power supply isn't suitable for core >memory, but it might be for semiconductor. The keyboard and display >are going to be useless. The backplane, CPU, power supply, and >teletype interface are the only parts of the VT14 that you're going to >end up using. I wouldn't call that "easy", nor would I call the >result a "PDP-8/E". Yes, and the power supply isn't useful unless you're using something other than core. And how many slots does the backplane have? Yes, it's possible, but given what I know now it's not easy. It's a source for a donor CPU board set, and maybe a TTY interface (assuming it's KL8 compatible) and that's about it. Possibly workable with the recent semiconductor memory boards. Oh, and of course, no front panel, making it hard to do anything useful unless you reprogram the MR8-F. -Rick

10 years, 5 months

Open source Nova 3 assembler

by shadoooo＠gmail.com

Hello Mark, well I suppose it would be very useful for this kind of operations. And as the whole read operation would be in the control of the PC, you could retrieve the whole disk, or a part, or a single sector.. whatever you want. The first step is to debug it and let it work with SIMH. Then I will try it with my 8" double floppy unit. At this time, adding support for any other drive would be a matter of knowing the peripheral control registers and producing a set of scripts from these informations. I will keep you informed about it. Thanks Andrea

10 years, 5 months

IBM 5170 AT 286 bios: how to add a new HARD disk

by jws＠jwsss.com

On 7/19/2014 2:08 PM, Enrico Lazzerini wrote: > I managed to find a bios for an IBM 5170 AT 286 Type1 Mainboard. It is > here: 30aprile1989 (list here: > http://ibm-pc.org/firmware/ibm/5170/5170.htm) > In practice I have manually added the number of cylinders, heads, and sect > / trk that allow the machine to recognise a disk IBM 250MB. At this point > regularly boots DOS. > But I wish to program these data permanently in the bios. Does anyone know > what program to use and give me the procedure? I tried with BIOSUTL, but > the new EPROM do not boot the machine. > With BIOSUTL i made what follow: read actual BIOS, you can add new disk > geometry parameters at free 47 position, then you have to recalculate bios > checsum, then BIOSUTIL devides BIOS into EVEN and ODD file so i can finally > program them into two 27256 150nS eprom. > Thank you > Enrico > Enrico, I suspect you do not have a good checksum on your image, unless you took pains to change that as well as the table Once you have modified your table, you have to bring the sum which will be visible in the bios space at F000:0 thru F000:ffff back to 0. A simple checksum of the data is all that the bios does. See below. I have patched numerous bios images, but always have to add a fudge in some byte somewhere to bring the simple sum below back to 0 overall. Jim I used a copy from bitsavers for the listing below. Had to clean up the OCR a bit :-) http://bitsavers.trailing-edge.com/pdf/ibm/pc/at/1502494_PC_AT_Technical_Re… If you look at the PC At tech reference, bios listing you can see what they do: On page 5-36, during startup ROS_CHECKSUM is called to check the roms. On page 5-67 (PDF file page 205 on bitsavers) EXTRN ROM_ERR: NEAR ;---------------------------------------- ; ROS CHECKSUM SUBROUTINE ; ;---------------------------------------- ASSUME CS;CODE, DS:ABSO POST3: ROS_CHECKSUM PROC NEAR ; NEXT ROS MODULE SUB CX,CX ; NUMBER OF BYTES TO ADD IS 64K ROS_CHECKSUM_CNT: ; ENTRY FOR OPTIONAL ROS TEST XOR AL,AL C26: ADD AL,DS:[BX] INC BX ;POINT TO NEXT BYTE LOOP C6 ; ADD ALL BYTES IN ROS MODULE OR AL,AL ; SUM = O? RET ROS_CHECKSUM ENDP

10 years, 5 months

PDP-8 VT8-E

by rick＠rickmurphy.net

At 02:34 PM 7/20/2014, Eric Smith wrote: >On Sun, Jul 20, 2014 at 5:46 AM, Jerome H. Fine ><jhfinedp3k at compsys.to> wrote: > > My question was not intended to be limited to the VT14 AS SUPPLIED! > >Nor was my answer. > > > Rather, could the VT14 have been relatively easily modified (i.e. > without > > major changes AND without having to reverse the changes OTHER than > > to removing them with ONLY a screwdriver or other similar tool within > > about 30 minutes) to be able to run PDP-8 software. The VT8-E was a set of modules that turned a PDP-8 into a terminal. In one mode, it DMA'd a chunk of memory and displayed the contents. Interesting to fire it off when running memory checks, but that's about it. It also had a bitmap font generator. You could run an OS with the VT8-E running, but you couldn't run anything like OS/8 with the VT8-E as the console as it ate too much memory and wasn't in any way KL8 compatible. I don't know anyting about a PDP-14, but it it used a VT8-E, it had to be an Omnibus machine with Omnibus memory, so it could easily be turned into a PDP-8/E with the right CPU card set. -Rick

10 years, 5 months

I've got some VAXStation VLCs available

by chuck.mcmanis＠gmail.com

This the smallest VAX you can own :-) I've got 6 or 7 I would like to get adopted. Available free for local pickup (Sunnyvale, CA) or if you're willing to pay packing and postage I can take them to the local shipping shore and have them sent off to you. --Chuck

10 years, 5 months

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test-drb July 2014