test-drb November 2007

test-drb@ccmp.vtda.org

229 participants
508 discussions

by ajp166＠bellatlantic.net

> >Subject: Tarbell is making me insane > From: Grant Stockly <grant at stockly.com> > Date: Tue, 06 Nov 2007 23:07:13 -0900 > To: cctalk at classiccmp.org > >I'm about to go insane. > >Here is what I have: >-Fake Altair (rock solid in everything but tarbell) >-Tarbel 1011D >-Tarbell 1011A, which SEEMS to be better than the 1011D. >-4xMITS 16MCS 16k memory cards >-5xSEALS 8k SRAM >-2SIO >-MITS Rev0 CPU > >Anyway...it doesn't work at all if I have a 16k memory card and an 8k >memory card. The 1011A works best (gets the furtherest in all >tests). If I'm lucky it asks me how many disks I have! > >It also doesn't work with 3 seals 8k cards. > >When I put in a CompuPro active terminator on the end of the bus, the >computer goes crazy and doesn't do anything. Installing an >"Industrial Micro Systems" terminator from 1980 it changes >operational characteristics, but still doesn't quite do it. > >I had been trying to make the stupid thing work for months, on and off... > >Well, I decided to stop trying to limit the number of cards on the >bus. I put in 5 8k seals cards and the stupid thing boots and runs >commands. Before while loading BDOS it would most of the time report >corrupted or missing sectors. Or just print trash. Now I can run >DISKDMP and programs like that. > >After working flawlessly for a few minutes its back to crazy. I can >single step through the tarbel boot program and see it going crazy... : ( > >I'd like the thing to be rock solid with minimal memory cards. > >Can anyone think of WHY the tarbel card is so much trouble? I burn >EPROMs all day long with this Altair. It takes 3 minutes to burn a >1702 and I've never had one fail! I can also leave it playing music >for all night long with no problems!!! > Welcome to S100. First ANY CARD that uses wait (many disk controllers stall the cpu waiting for data) will tend to corrupt Dram depening on the DRAM card and timing. I found 884MCDs problematic until I converted them to a pin compatable static rams. The S4Ks sorta worked but not with DMA. I don't have info on tarbel 1011 seris FDC. The schematic on hand I could comment more. However 8" DD with 2mhz 8080 is very difficult to do as single density is already pushing the 8080 through some very tight software loops. Of all the cards the SEALs 8k and the PT 8Ks were about the best. Also sounds like oneshot problems. Check cpu timing. Even small timing errors tend to magnify bus noise issues and incompability problems. Some cards were timing incompatable due to how they decoded status signals and tended to be either sensitive to bus noise or cause bus noise. Also HEAT. That thing despite a very heafty noisy fan and cover mods didn't like heat. FYI: the timing of the oneshots drifts with heating! In general It sounds like the usual problems I had with the Altair prior to retirement. It was always conditionally stable, make a change start over again. It Improved when I replace the CPU one shot clock with an 8224, better still with a WAMCO "quiet mother" backplane and improved more when I went to a Z80 card (NS* ZPB). near the end the only thing stock was the front pannel (even the connecting leads were shortend and extra grounds added). The 8800BT has none of these problems, It has both tarbell and MITS floppy controllers. Allison > >I need help!!! : ( > >Grant

17 years, 1 month

Tandy Logix-Kosmos (was: Re: Ferranti Logical Computor (1951) )

by blstuart＠bellsouth.net

> > http://oldcomputermuseum.com/logix_kosmos.html > > That was the first one I had - the overlays inside were, IIRC, printed > tissue paper. Me too. I still remember how I would forget that they were not symmetric, so if you put them in backwards the separators between the output values and the plastic separators between the lights don't line up. > > Mine died of corrosion on the contacts, and was (regrettably) > > trashed, I'm pretty sure. > > I remember the contacts weren't great on the best of days. I think my > step-mother threw mine out when she decided my room was too messy. > :-( Yeah. The contacts were my biggest source of frustration. I probably would have done a lot more with it, if I hadn't had to wiggle wires and adjust the contacts for every "program" on it. Believe it or not, I still have mine. I even have it upstairs where I can find it. Not that I've used it any time recently. > My only real complaint with it as a teaching tool was that even though > I did all the projects, there was no abstraction of the underlying > concepts presented. I agree. They also didn't do a good job of clarifying that the device only implemented combinatorial logic. As I recall, I got it before the idea of a stored program really clicked with me. Unless I missed it, they didn't have a discussion in the manual that said, this "computer" does this, but real computers also have memory that stores not only data, but instructions too. BLS

17 years, 1 month

Televideo Terminals TS-800A (UK)

by james＠attfield.co.uk

I have just been told about the availability FOC of the following: 3-off Televideo TS-800A terminals with keyboards (believed RS-232 and believed serviceable) 2-off IBM Monitors 5153 (condition unknown but I had one a while back and it was serviceable) 2-off IBICO printer calculators 1050 and 1060 (condition unknown) These are headed for the dump unless a home is found fairly quickly. I don't have a need but will gladly put any takers in touch with the owners or in a pinch will collect and store for a short time pending final collection. Sorry, no shipping possible or arrangements outside the UK. Current location is Coventry (UK) but equipment can be relocated to Redditch (UK) or Stourbridge, West Midlands (UK). I don't imagine the current owners will be keen on protracted or complex arrangements as they just want rid so preference is likely to be given to someone willing to take the lot. A chit will need to be signed affirming the kit has been removed so that the owners can substantiate that it has not just been dumped for audit purposes. Any interested parties should email me off-list at james/at/attfield/dot/co/dot/uk. Please be quick - I'm pretty sure it won't be kept for long. Jim This outbound email was scanned by Norton AntiVirus 2007 when transmitted and all reasonable precautions have been taken to ensure that this email was free of current known viruses and other malware when sent. Please be aware that between here and you are an indeterminate number of email relays so you should not rely wholly on this and ensure that you have adequate up-to-date protection against viruses, worms, spyware and trojans etc. The sender can not be held responsible for any undesirable elements or malware in a received email sent by him. Please note that if your reply originates from GOOGLE, HOTMAIL, MSN or YAHOO it may never reach me as these domains are blocked.

17 years, 1 month

Commodore 64 MIDI workstation?

by woyciesjes＠sbcglobal.net

ISTR a web page I saw the otehr day, where a guy showed how to modify a Commodore 64 to do stereo output, made the case smaller, etc. Does this ring a bell with anyone here? -- --- Dave Woyciesjes --- ICQ# 905818 --- AIM - woyciesjes "From there to here, From here to there, Funny things are everywhere." --- Dr. Seuss

17 years, 1 month

TS03

by tponsford＠rnsmte.com

Hi All Picked up a good lot of pdp stuff at the auction yesterday a Netcom 11/23, and a H960 rack which I've been looking for to put my 11/04 in. As a bonus, the rack came with a TS03 which I've read is a re badged Kennedy 9700, a 9-track tape drive w/ 7" reels. The rack had the expansion Unibus box with the TMB11 interface, Doesn't the TS03 have a pertec interface and if it does, wouldn't a third party emulex or diloq unibus card work? Any advice or gotchas on this tape drive would be appreciated!! Cheers Tom Ponsford

17 years, 1 month

Kaypro 4/84 questions

by ajp166＠bellatlantic.net

> >Subject: Re: Kaypro 4/84 questions > From: Brian Wheeler <bdwheele at indiana.edu> > Date: Wed, 07 Nov 2007 11:26:54 -0500 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On Mon, 2007-11-05 at 17:54 -0400, Roy J. Tellason wrote: >> On Monday 05 November 2007 13:13, Brian Wheeler wrote: >> > * I'd like to replace the 2nd drive with a 3.5" floppy. I've found a >> > Sony HD drive along with a power and plug converter. Knowing that PCs >> > use a twisted cable scheme, what things should I be aware of when >> > cabling in this new drive? >> >> The twist in the cable was to not have to worry about jumper settings which >> you had to deal with prior to that point. Those drive select jumpers are >> marked, depending on the brand, either 0-3 or 1-4 on the drive electronics, >> with the first two choices being the ones commonly used (0 and 1, or 1 and >> 2). The cable with the twist setup has both drives set to the second choice, >> so you probably won't need to worry about messing with anything there, >> selecting the drive should be apparent as Kaypros tend to leave the light on >> all the time. >> >> > Will it be supported in some manner by the software? >> >> Hm, kinda doubtful, though I couldn't say for sure as it's been a long time >> since I dove into those particular interface specs. >> >> > Its not a big deal if it turns out to be a 360K 3.5" floppy, as long as its >> > readable by my linux box. >> >> That might just be what you end up with. Do tell us when you find out, I'd >> be curious to know... >> > >I've got the 3.5" drive installed and cabled and it seems to be working >rather well. I ended up using vice grips to get the screws loose in the >drive cage since the heads kept wanting to strip. As I suspected, it >really thinks its just a DSDD 5.25" drive. I formatted a disk using >mfdisk as an IBM 9 sector DS disk and could read it (as 360K) without >problems on my linux box. > >The drive I ended up using was a chinon FZ-357 which has a jumper for >RDY as well as drive select jumpers. It also had the interface pins on >the same side as the original disk so I could use the original cable. >All of my other 3.5" drives had it on the other side, but the cable >wasn't long enough to shift sideways enough. > >Its weird when it does a format since it counts tracks from 0 to 79 but >its really counting cylinder 1 as tracks 0 and 1, etc. > >However, trying to read a kaypro formatted disk isn't working. It reads >4K and then fails. Anybody used setfdprm on linux to set up reading >kaypro iv/10 disks? They look like they're 10 sector (numbered 0x0a - >0x13), rate=2 disks. You may have to notify the software of what format is being used. >I'll probably mount the 5.25" DSDD drive in my linux box as well, but >it'd be nice to know how to read disks without hassle :) > >Now for some more questions: > >* is it possible to run CP/M 3.x on it, or am I limited to 2.2G? Yes, but without any banked memory. >* what's the J9 header for? It looks like it has 8 data bits and 8 >address bits wired to it (at least according to the schematics I've >found). Seems like it'd be possible to hang a home-made IDE interface >onto it (if I ever get time/inclination) Its host interface for WD1001HDO HDC, Sorta like IDE save for the board was bigger than the drive, it wasn't integrated, it was 8bit and the registers were slightly differnt. To do IDE with that should be easy as its basiccally the process or bus for IO. There will not be software support (BIOS) unless you do it. Allison > >Thanks to all of the suggestions and advice! > >Brian >

17 years, 1 month

cctalk Digest, Vol 51, Issue 18

by compoobah＠valleyimplants.com

On Nov 7, 2007, at 2:00 PM, Chuck wrote: > On 7 Nov 2007 at 10:58, Richard wrote: > >> Umm... IIRC, Xenix was a unix implementation that didn't even require >> virtual memory, ran on x86 architectures (386?) and required very >> little memory; certainly much less than Win96 since Xenix was >> available in 1986. > > Early Xenix ran on a 286. I don't think it ever ran on anything > less. I have an early Microsoft MSDOS 2.0 OEM announcement that > talks about eventually unifying Xenix and MSDOS. I guess that goes > in the same category as Microsoft OS/2 2.0... There were versions for Lisa and (not used but seen pictures of) an 8086 version - perhaps on one of the early Altoses. Later versions of Xenix were 286 and up, and later (with XENIX System V 386) 386 and up.

17 years, 1 month

Tarbell is making me insane

by ajp166＠bellatlantic.net

> >Subject: Re: Tarbell is making me insane > From: Grant Stockly <grant at stockly.com> > Date: Wed, 07 Nov 2007 23:35:01 -0900 > To: "General Discussion: On-Topic Posts Only" <cctech at classiccmp.org> > > >>Changing the crystal would half the data rates making it right for >>5.25" floppy. >> >>One of the modes all the contrllers that use hang mode (wait), is >>sector never found. Wrong clock rate will insure that. > >I was also considering that at 2MHz instead of 4 the FDC controller >will be operating close to its limits and may need the wait >state. What was happening was probably a missed wait state. More like the data rate for the board was halved 250kbits/sec and the data was never being read. That will hang the system as the FDC is waiting for the data and at the wrong rate it will never arrive. The Clock crystal is used to derive the data rate for reading and writing. >>Both work. The logic however uses the 8T97 and tristates it when >>not needed (board not addressed) which is a "legal" way to do it >>though it seems like more effort. >> >>Of course using high is active and mixing than with low is active was >>a dumb thing too. Even Tristate asserts a better low than a high. > >The front panel buffer is hard wired on, so the Tarbell was shorting >out the panels XRDY. That too. On front pannelless systems thats not an issue. > >I reviewed the 1k memory card and it does tristate it like you >said. My problem with the 1k card way back then was that the MITS >documentation puts both on the PRDY line. In my two systems this was >no good. The transients would corrupt the bus cycle. This was found >when working with an altair laying on a wooden table. It wasn't in a >metal case. I never tried putting both on the PRDY line when it was >in an enclosure. I imagine it would have worked better in the case >since I've never read any errata on it, but I wanted to play it safe. It would ahve worked btter is the rams used wer 600ns rather than 1uS and the wate states never needed. >If you want to talk about media abuse...1.4MB disk with the HD hole >covered, formatted to 71k : ) That works. > >One of my problems MIGHT have to do with the 16v and 8v supplies not >turning on at the same time. I will have to investigate that more... Why do they not turn on at the same time? All the altairs I know of the switch was on the AC side and it all came up soon as AC was applied. Allison

17 years, 1 month

VCF: 5100 emulator?

by frustum＠pacbell.net

I recall seeing that someone was going to show off their software emulation of the IBM 5100 computer at the VCF that just happened. Did it make an appearance? I just checked the VCF exhibitor list and didn't see it there anymore. Was it retracted? Does anybody know who developed it? I'm quite curious to learn more about it; writing such an emulator was on my long term TODO list, but I'm glad somebody beat me to it, as there are many other projects on that same list. Thanks.

17 years, 1 month

modern serial terminal

by mark＠wickensonline.co.uk

I have an Axel Platine terminal that seems to fit all the requirements - except maybe that the terminal emulation for older computers might be a bit lacking. Size of a 'Letter/A4' piece of paper, an inch thick, uses standard PC keyboard/monitor/LCD and uses 8W of power. They can be bought cheaply of EBay (in the UK anyway) Just a thought Mark

17 years, 1 month

← Newer
1
...
39
40
41
42
43
44
45
...
51
Older →

Jump to page:

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 November 2007