test-drb

test-drb@ccmp.vtda.org

101090 discussions

by wim＠hackbox.be

I've followed Tony's advice and went step by step, one board no chips, chips loaded, second board no chips, measuring at each step. Finally all seemed fine, I fired it up and now I've got RAM from 0000 all the way to 7FFF :) Next essential thing is the Load routine (from audio) that doesn't seem to work. I wrote a routine to read bytes from the ACIA just like the JBUG load routine does and simply quits when the first byte is read. It loops until I start to play the audio file, so it actually detects that. However when I make it loop until it finds a non zero data byte, it never stops. So I thought all the analog stuff is working up to the ACIA and the latter must be broken. Tried replacing it with no success so far. Anyway, the kit is so well documented that I should have no excuse of not being able to pinpoint the problem, learning a lot along the way... Also, what are the best tools to encode/decode KCS audio ? From the ones mentioned on the wikipedia KCS page I had success only with the perl script, but that's only one direction. Wim.

15 years, 5 months

Making Magnetic tape

by pontus＠Update.UU.SE

Hi Speakin of making punch cards and paper tape. What would it take to make DECtape? A roll of adhesive tape and rust? /P

15 years, 5 months

HUGE old computer lot, maybe some gems

by tshoppa＠wmata.com

> Same guy posted to the VCF Forum about this. He wont ebay, craigslist is > full of "scummy people" and "advertising costs money" so in other words he > will pay to junk it. Could be wrong but somewhere in there he stated it was > purchased for $4500 or something? Why do people blow that kind of money > without a plan to profit? Sure there are some units in there worth selling, > but that is if they are complete, cleaned up, and working otherwise they > will go for nothing to somebody looking for parts or a project. "Plan to profit"? More typically it's a passion that simply has gone sour or has just faded away. After it fades away the time, money, storage costs seem different than when the passion was strong and the acquisition was the main thing - but then real life intervened and he wants something back. That something might be identified as money and I will agree that something's missing, but it is not actually money. Tim.

15 years, 5 months

1103/A trivia question

by mark.kahrs＠gmail.com

Sorry Tony, I "misspoke" --- the Alto memory Refresh task must run otherwise the memory will wilt. The precharge is generated via chip select and a carefully chosen inverter delay line.

15 years, 5 months

trying to save a GPS

by oldcpu3＠rogerwilco.org

Curtis H. Wilbar Jr. said: > I know this isn't old... but I'm trying to rescue an Omnitech 16878-US > GPS from the recycling bin..... > > [snip] > > Anybody have one of these ? I have one. As is my usual habit when I get a gadget with accessible storage, I imaged the SD card immediately right out of the box. Restoring that image (about 978MB) should get things back to factory condition, software-wise. Contact me off-line. -- Jared

15 years, 5 months

Terak page updates

by jfoust＠threedee.com

It's been a decade, and with a recent request for scans from Al, and hearing of others who've found Teraks, I thought I'd refresh my page. Notable additions include: - Pictures from inside the Terak building circa 1980 - Terak user group newsletters - Terak user group software lists I think I have a few items up there that Bitsavers doesn't have, so feel free to grab a copy. - John

15 years, 5 months

looking for dump of Tektronix 4023 chargen ROMs

by jonnosan＠gmail.com

Howdy, I'm currently putting together a simulation of the "SacState 8008 machine" (the machine described at http://www.digibarn.com/stories/bill-pentz-story/ ) This computer was a series of custom cards that plugged into a Tektronix 4023 terminal, and used the 4023 for I/O. Therefore in order to simulate the SacState 8008, I need to start by emulating the 4023 terminal. Having a copy of the character generator ROMs would help a lot with making that emulation authentic. According to the 4023 service manual, the chargen ROMs are: Upper Case ROM A - part number 156-0147-00 Lower Case ROM A - part number 156-0401-00 Optional Ruling ROM B - part number 156-0401-00 Would anyone have a dump of any/all of these chargens? Regards Jonno

15 years, 5 months

Installing Ultrix 4.4 on a DECstation 5000 Model 240

by robert.jarratt＠ntlworld.com

I am trying to install Ultrix on to this machine and it is failing very early in the process. It is failing at the stage of detecting the disks with an "invalid block size" error. I am using a CR-506 CD-ROM drive and the disks I have are RZ56 and RZ57. The disks already have NetBSD installed and I intend to replace NetBSD on one of the disks. I am not sure if the error is referring to the CD-ROM (despite the fact that it has already booted off the CD-ROM) or if perhaps it does not like something about the way the hard disks are formatted. Or is it some other problem? The system runs NetBSD just fine, so I don't think the disks are faulty. Any suggestions? Thanks Rob

15 years, 5 months

1103/A trivia question

by mark.kahrs＠gmail.com

To Tony: The non-A needed precharge. That's what the Alto memory refresh task does. What do I win?

15 years, 5 months

1103s

by tshoppa＠wmata.com

> Sometimes the data sheets for an SARM (or whatever) indicate the > row/column structure. Not that it matters, I've not come across an SRAM > that has, say, faster access time from a change in row address than a > change in column address When I once asked why there were so many different PDP-11 memory diagnostics, (beyond just unmapped vs mapped vs whatever processor diffs) I was told that it was because each was structured to hit the row/column drivers and induce known pattern-sensitive failure modes particular to the core stack or chips in use. Tim.

15 years, 5 months

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