test-drb

test-drb@ccmp.vtda.org

101090 discussions

by oldcpu2＠rogerwilco.org

[Repost, now that the list is back up... (Thanks, Jay!)] My old Novell 2010 CP/M computer[1] has suffered a failure in the Data Technologies Corp. DTC520 controller. IIRC, this controller can support up to 2 MFM/ST506/ST412 drives and 4 floppies. In my case it's only hooked up to a single Seagate ST-506 (5MB! Woohoo!), and a single Shugart SA450 5-1/4" floppy. Apparently this controller was not too uncommon in the day. In my case, the DTC520 is installed in the disk subsystem that's separate from the main terminal/computer, and they no longer will talk to each other. The problem seems to be related to the section that handles the IO between this controller and the CPU box. I've replaced one chip (74LS33) that was showing some serious corrosion on the pins/legs, thinking that maybe some of that had migrated into the IC die itself, but no change in behavior. It's still indicating a screwy logic level on one of the gates, but it must be coming in on the inputs. I need a schematic to help me trace the signals. I can't locate anything online. Does anyone have anything that could help me out...schematics, technical description, etc.? Many thanks. - Jared [1] Before there was Novell, Inc., the networking software company, there was Novell Data Systems (NDS), c. 1979. They had the big idea of creating a "Data Management Computer" (DMC) around a 68000, which acted as a micro-mini-mainframe for up to 24 intelligent terminals. While this project never really got off the drawing board, around 1980 NDS added (yet) another CPU to their intelligent terminal and stuck CP/M 2.2 on it. They sold a handful of these (I ended up with one) in an effort to generate a little cash flow while the 'real' project of the DMC was still in works. In the end, it was all a little too late and NDS collapsed in the latter half of 1982. It was at this point that Ray Noorda was recruited to revive the company, and in January 1983, Novell, Inc. was (re)born with the focus of networking primarily IBM PCs. The DMC, by the way, ended up becoming a file server (as opposed to Corvus', 3Com's, et al, 'disk (slice) server' technology) and the rest is history. Later, around 1988, Novell, Inc. dropped all hardware products to focus exclusively on their NetWare software.

17 years, 8 months

Schematics of Atanasoff-Berry Computer logic circuits?

by ed＠ed-thelen.org

> Message: 8 > Date: Fri, 29 Aug 2008 13:47:07 -0800 > From: Brent Hilpert <hilpert at cs.ubc.ca> > Subject: Re: Schematics of Atanasoff-Berry Computer logic circuits? > To: General at invalid.domain, "Discussion at invalid.domain":On-Topic and > Off-Topic Posts <cctalk at classiccmp.org> > Message-ID: <48B86E5B.C9A63D91 at cs.ubc.ca> > Content-Type: text/plain; charset=us-ascii > > William Donzelli wrote: >> >> > I think, rather, that that's a good portion of the explanation of why they >> > were so slow. >> > Ballpark example, take a 12AU7: the sum of the grid-to-plate and >> > grid-to-cathode capacitance is around 3 pF. Suppose the network resistance >> > feeding the grid circuit is 250 KOhm, that's an RC time constant of 0.75uS, >> > a little better than just 1 MHz. (R can be reduced of course but power >> > consumption is then on the climb.) >> >> Well, OK, i could buy that, but from what I have seen from the >> circuits and construction of tube logic circuits is that the 3 pF is >> not much compared to all the stray capacitance kicking around due to >> construction techniques. > > I'd say point-to-point wiring becomes problematic when you start getting going > into the higher shortwave / low VHF, and granted it becomes an issue in a > physically large system, but it may not be bad as you might think. The 10MHz > stage of the HP 524 counter is done with 'rats-nest' point to point wiring with > components on tag boards separated by wires from the tube sockets, even for the > grid circuits. The key was they went to high-frequency pentodes instead of > duo-triodes, low-R circuits, diode clamps, 1% resistors: hi-speed was > 'possible' but very expensive to accomplish. > Looking up the plate to grid Direct Interelectrode Capacitance, grid to plate is 1.5 pf However , the Miller effect makes that quite interesting - depending on the effective stage gain, the effective capacity is increased by the effective stage gain - which is a big frequency limiting (and stability) factor - basically why pentodes and tetrodes were developed, (reduce the Miller effect and move the cut-off frequency up a way. The grid to plate capacitance (and the accompaning Miller effect) make trying to get stability in a tuned plate, tuned grid circuit "interesting". (Interesting enough with proper tetrodes ;-)) I ain't a curcuits guy, but remember stuff, the wrong stuff - Ed Thelen

17 years, 8 months

HUGE amount of documentation - FREE

by timdeaton＠yahoo.com

I have documentation on terminals, monitors, motherboards, add-in cards and all kinds of stuff I collected over 20 years of systems integration work (1977-1997). FAR too much to list or categorize. About 300# I do not want to see it go to waste. Anyone who will make a good home for it can have it at no cost other than you have to come get it or arrange to have it picked up. Located in Shelbyville, Indiana (Indianapolis SMSA) PLEASE come get this and give it a good home. I am long retired and need my basement office space! I have already give away TRUCKLOADS of hardware and software...all that remains is this documentation. Tim Deaton

17 years, 8 months

HUGE amount of documentation - FREE

by timdeaton＠yahoo.com

17 years, 8 months

Wanted: vacuum tube logic circuits

by wbblair3＠yahoo.com

William Donzelli wrote: > I have exactly one 12U7 in stock. I have a few > 12K5s, as well. > > > > I've now got a number of different dual triode > tubes to try from a local electronics shop that has a large > collection of tubes from former TV and radio repairmen. $1 > each and they have a B&K 707 tube tester to test them > on. > > Well, in case you wanted proper space charge tubes for your > digital logic experiments. Oh, now I understand, thanks. Well, there were a few space charge tubes in their $1 bin and they had six of the coveted (for audio) and relatively rare new old stock 6GM8s in their new tube section that they sold me for $3.75 each (they didn't know what they had) which was their cost in the 70s. They were trying to clear out their extensive new tube inventory of types that they hadn't sold for quite some time. With a car radio tube like the 6GM8 that is now of interest primarily to tube audio hobbyists, I can see why they hadn't sold one in a _long_ time.

17 years, 8 months

Unusual altair front panel...

by cctalk＠solivant.com

>> Bill Sudbrink wrote: >>> >>> I've never seen an altair with a front panel like >>> the one on ebay item #160276656912. Has anyone else? >>> Is is located close to where I work and I'm thinking >>> of asking the seller if I can stop by and have a look. >>> If it's nothing unusual, I won't bother. >> >> Nobody has an opinion on this??? Or is everybody about to >> snipe the auction? >> > I think it is interesting... > > Looks to me like an original Altair that was styled in what I call the > third generation of Altairs.. Which included the version with a simplified > front panel. > > George Rachor > Hillsboro, Oregon > If you look closely at some of the internal pictures, you'll notice that the card support rails are unusual for an 8800, too. Geoff Harrison.

17 years, 8 months

Schematics of Atanasoff-Berry Computer logic circuits?

by wbblair3＠yahoo.com

Chuck Guzis wrote: > Were these the special "space charge" tubes? > e.g. 12J8, 12U7, 12DK7, 12DL8, 12CX6, 12DE8, 12CN5, 12BL6, 12DS7, > 12AC6, 12AD6, 12AE6, 12AE7, 12AF6, 12AJ6 or 12AL8 (I've probably > left out a few)? Yes, that's some of them. There were 41 types.

17 years, 8 months

Wanted: vacuum tube logic circuits

by wbblair3＠yahoo.com

Over time, I've seen an occasional link here to an on-line copy of some 50's or early 60's electronic hobbyist magazine describing a binary project of one kind or another using vacuum tubes. If you have such a link or know of any bibliographical references to such articles that might be useful in obtaining a hard copy of the applicable articles via library-based research and inter-library loans, please post it here. I have in the past found plenty of relay-based logic circuits on-line but am having a really tough time finding any binary tube circuits with component values. If there's enough material submitted to justify it, I might start a web page on this topic or, at least, a blog that links to the relevant materials on-line. Thanks.

17 years, 8 months

Has anyone ever tried to make 1960s-type incandescent digital displays?

by ethan.dicks＠usap.gov

Hi, All, I was recently watching "Goldfinger" and oggling the countdown timer on the bomb. I don't think I've ever seen that type of display technology up close, but in principle, it shouldn't be hard to replicate. <http://www.vintagecalculators.com/html/calculator_displays.html#Incandescent> I was thinking that some sort of modern CNC would make short work of the digit faces - just CAD up some outlines and bang out a few sheets. Alternately, a pantographic sign engraver might do the trick, with suitable templates whipped up either by hand on on a CNC. The compact design for the type marked "KGM M4" looks intriguing as well - a few slits cut in an aluminum back, and a simple PCB layout for the bulbs (though I must confess I was contemplating white LEDs rather than bulbs for a variety of reasons, including longer life and simpler drive circuits). As for driving it, I was thinking about something like a '145 O.C. decimal decoder (as found in Commodore PET keyboard circuits and KIM-1 memory decoder and LED decoder circuits) per display. They aren't particulalty expensive, and all you'd have to do is pipe in 4 bits and let the '145 do all the work. Nixies and other contemporary (and now faded) display technologies are cool, but any of the glass-envelope types aren't exactly feasible to reproduce in a home workshop. -ethan -- Ethan Dicks, A-333-S Current South Pole Weather at 29-Aug-2008 at 02:50 Z South Pole Station PSC 468 Box 400 Temp -88.6 F (-67.0 C) Windchill -131.7 F (-90.9 C) APO AP 96598 Wind 12.2 kts Grid 56 Barometer 657.5 mb (11489 ft) Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html

17 years, 8 months

cctech Digest, Vol 60, Issue 47 - govliq: 12 HP 7907A disk drives

by jondjohnston＠hotmail.com

------------------------------ Message: 25 Date: Fri, 29 Aug 2008 13:20:56 -0600 From: Richard <legalize at xmission.com> Subject: govliq: 12 HP 7907A disk drives (Ogden, UT) To: cctalk at classiccmp.org Message-ID: <E1KZ9Wi-0008Iw-9U at shell.xmission.com> LOT (20) DISK DRIVES TO INCLUDE: (12) HP 7907A DISK DRIVE UNIT LR28576 (1) MEGA DRIVE ENTERPRISE 8 FIXED/ REMOVABLE DISK DRIVE UNIT (7) PANASONIC KXL-RW21A PORTABLE CD-R/ RW DRIVE FOR USB INTERFACE 6X WRITE/ 4X REWRITE SPEED <http://cgi.govliquidation.com/auction/view?auctionId=1903614&convertTo=USD> As before, if anyone wants these, I'm willing to pick them up from govliq and help you with packing and shipping. ____________________________________________________________________________ _____________ Richard - wow, what a big help for you to pick up, especially with us being so far away. Thanks. We are extremely keen to obtain 3 of the 7907A and would be happy to pay $100 each plus shipping (we would ship to Ca). Anyone else interested in going in on this? Cheers, Jon. www.hpmuseum.net.

17 years, 8 months

Unusual altair front panel...

by wh.sudbrink＠verizon.net

I've never seen an altair with a front panel like the one on ebay item #160276656912. Has anyone else? Is is located close to where I work and I'm thinking of asking the seller if I can stop by and have a look. If it's nothing unusual, I won't bother. Bill Sudbrink

17 years, 8 months

free: 2 old imacs + G3 w/o a hard disk; Boston area

by brad＠heeltoe.com

[I'm not sure if this ever got out during the black out] I have 2 old imacs (blue and purple) and an G3 imac (clear and blue) I want to give away. The imacs work and have disks. The are a little scuffed up but in reasonable condition. The G3 (300mhz) works but has no hard disk (it's just an ide). It's in good condition. I think I have most of the original paperwork for it. No keyboards or mice or power cords. Would anyone like them? I'd rather not toss them. I am in the Boston area. -brad

17 years, 8 months

Intel 31014 Chip?

by marvin＠west.net

This is a duplicate, but it appears the first post got lost when the listserver went down. I've got an Intel 31014 chip, but can't find any information about it on the web. The 31 first two numbers imply it is a RAM chip, but that is about all I can guess. Maybe it is one of those $5K RARE chips :). A picture is at http://www.west.net/~marvin/i-31014.jpg. Any help would be appreciated. Thanks!

17 years, 8 months

Wanted: vacuum tube logic circuits

by wbblair3＠yahoo.com

Chuck Guzis wrote: > Just before transistors began to be used in auto radios, "space > charge" tubes made a brief appearance, running their plates and > heaters from the 12v battery. No vibrator supply. Some of the > earliest transistor designs used a transistor only in the audio > output stage, among them the Delco "Wonder Bar" models. > Jeff Duntemann has a nice page on this stuff, along with datasheets: > http://www.duntemann.com/12vtubes/12vtubesindex.htm Yes, I found that excellent site back when I was playing with low-voltage tube headphone amps and I have a copy of the Tube Collector Magazine "Car Tubes" article cited there. However, the tube amps I built from modern plans were ones that used common dual triodes like the 12AU7 but with _very_ low plate voltages. The reason for this is the scarcity and, as a result, expense of the low-voltage "car tube" types most useful for audio amps and, unfortunately, logic circuits (12U7, 6GM8). If for some reason I can't get any of the most common and cheapest high B+ dual triode tubes to work in a logic circuit at low plate voltages, then I'll have to go with something like the dual diode, single triode "space charge" car tubes that aren't in demand by audio enthusiasts making them much more readily available and much cheaper. A functional hobbyist demonstration of tube logic that's cheap and uses low voltages is my goal.

17 years, 8 months

cctech Digest, Vol 60, Issue 46

by michaelgreen42＠comcast.net

Hey Josh long time no talk. I'd be willing to take the TRS-80 stuff from you. ------------------------------ Message: 5 Date: Fri, 29 Aug 2008 00:29:20 -0700 From: Josh Dersch <derschjo at msu.edu> Subject: Free stuff! To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> Message-ID: <48B7A550.2090308 at msu.edu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Well, now that the mailing list is back up I can list some stuff I need to get rid of :). Local pick-up in the Seattle area, only -- please. (Most of this stuff would be so expensive to ship it wouldn't be worth it anyway...) I'm willing to drive a bit to meet someone halfway if necessary. - IBM PS/2 model 25. In good shape but does not power up. Color screen, some manner of hard disk installed. - TRS-80 Model 12. Kind of rough, but with a little work it'll clean up. Runs, but power supply needs some work (was running fine while I was testing it but a cap let out the "magic smoke" and I haven't had a chance to recap it.). Has card cage expansion but no cards. Dual 8" floppy. - 5 boxes of TRS-80 Model II/12/16/6000 documentation. I bit off more than I could chew when I took this in, I hope someone can use this... all manner of manuals, if you're interested I can give you a list. - A Wang word processing terminal (I can't seem to find a model # on it). Heaviest terminal in the world. Powers up and beeps but that's about all I can get it to do. - Cipher M995S 9-track drive. Works. 1600 & 6250bpi, SCSI interface. Desktop enclosure. Heavy :). Josh ------------------------------

17 years, 8 months

Schematics of Atanasoff-Berry Computer logic circuits?

by gerhard.kreuzer＠liftoff.at

Hi, to make use of my spice tool set was indeed the first idea, but I dont have enough time yet so I didnt answer. Its no problem, there are still models for tubes available and its not to hard to make new models for the originally used tubes. The schematic is quite simple, maybe you can remember the first logic chips available where made in so called RTL (restistor Transistor logic), which is exactly the same as the ASM do, only the levels are shifted. Because of the problems with the resistor networks, the so called TTL chips are developed, which replaces some resistors by transistors. I am shure there is enough information out. Once you have seen how RTL works, you will easily find out how ASM works. Sorry, that I am short?with time, but I am very interested on this project and as I can spare some hours, i will join, if possible. With best regards Gerhard

17 years, 8 months

Apple II - AppleSoft Code Sample SIN curve in hi-res mode

by billdeg＠degnanco.com

Is it possible on an Apple II using hi-res mode to draw a nice tight sin wave?...and if so Does anyone have a code snippet example? If HPLOT is used only to draw straight lines, how does one draw curves in hi-res mode using an Apple II AppleSoft BASIC? I will continue to search the typical places. If anyone knows of a magazine with an example, I may have it too. Bill

17 years, 8 months

TI-99/4A items to be listed for sale

by ygehrich＠yahoo.com

Sometime in the next couple of weeks I will be listing a large number of TI-99/4A items for sale. Before I advertise the items elsewhere is there anyone here looking for any TI-99/4A hardware, software, manuals? Let me know at ygehrich at yahoo.com and I'll see if I have what you are looking for.

17 years, 8 months

Wanted: vacuum tube logic circuits

by wbblair3＠yahoo.com

IBM's Selective Sequence Electronic Calculator (SSEC) 305 page patent: http://new.scribd.com/doc/4963230/Selective-Sequence-Electronic-Calculator-…

17 years, 8 months

Wanted: vacuum tube logic circuits

by wbblair3＠yahoo.com

William Donzelli wrote: > > Unfortunately, according to the TOC available at the link below, it doesn't have anything specific > > about tube logic circuits, but it certainly does look like a goldmine of electron tube technical data: > > > > http://www.pmillett.com/Books/intro_RDH4.pdf > > You will likely have more luck finding stuff in the trade rags and > Proceedings of the era. Actually, in the category of data that I have easy, web-based access to, I'm finding that I'm having the best luck with patent searches. As I find interesting ones, I'll post the links. I plan to put them all at scribd.com to provide one-stop (free) shopping. To start, here's the link to the 207 page ENIAC patent: http://www.scribd.com/doc/4960983/ENIAC-Patent-US3120606 If anyone knows of patents likely to have good tube or relay logic circuit descriptions within them, please give me the patent numbers and I'll post the patents as PDFs on scribd.

17 years, 8 months

Discussion List Netiquette, Was: WTB: DEC PC04 Paper Tape Reader/Punch

by mardy＠voysys.com

On Aug 19, 2008, at 12:44 PM, Chuck Guzis wrote: > On 19 Aug 2008 at 11:45, Marden P. Marshall wrote: > >> Guys, two words "thread hijacking" > > Sorry, I was curious about the subject and thought to ask some > questions about the current line of discussion. I'll keep my > inquiring mind to myself in the future (fat chance). > > Cheers, > Chuck > > If the current line of discussion does not match the subject line, then the message thread has been hijacked. It is discourteous and disrupting to other members of the community who might be trying to follow the original subject. How would you feel if you had started a new subject only to later see the discussion taken in a different, unrelated direction. -Mardy

17 years, 8 months

ACCRC blog: It Ain't Dead Yet

by pdp11＠saccade.com

The ACCRC (Alameda County Computer Resource Center) has started a blog showcasing some of the more unusual equipment they get turned in for recycling: http://deadmeatmarketing.blogspot.com/ The about column says "Anyone with ideas about how to put this stuff to good use please leave a comment." My brief perusal turned up a Wang 600, a wire(!) audio recorder, and an WWII O-Scope. Actually, I think I still have a scope just like that at my Mom's house.... Cheers, jp http://www.saccade.com

17 years, 8 months

Free stuff!

by derschjo＠msu.edu

Well, now that the mailing list is back up I can list some stuff I need to get rid of :). Local pick-up in the Seattle area, only -- please. (Most of this stuff would be so expensive to ship it wouldn't be worth it anyway...) I'm willing to drive a bit to meet someone halfway if necessary. - IBM PS/2 model 25. In good shape but does not power up. Color screen, some manner of hard disk installed. - TRS-80 Model 12. Kind of rough, but with a little work it'll clean up. Runs, but power supply needs some work (was running fine while I was testing it but a cap let out the "magic smoke" and I haven't had a chance to recap it.). Has card cage expansion but no cards. Dual 8" floppy. - 5 boxes of TRS-80 Model II/12/16/6000 documentation. I bit off more than I could chew when I took this in, I hope someone can use this... all manner of manuals, if you're interested I can give you a list. - A Wang word processing terminal (I can't seem to find a model # on it). Heaviest terminal in the world. Powers up and beeps but that's about all I can get it to do. - Cipher M995S 9-track drive. Works. 1600 & 6250bpi, SCSI interface. Desktop enclosure. Heavy :). Josh

17 years, 8 months

Terak 8510 system on eBay (# 300248208909)

by classiccmp＠crash.com

It's listed for $199 plus shipping for the main unit, an 8512 additional 8" floppy, and an 8532-1 monitor. Includes keyboard, some floppies, and some manuals. It's been discussed here before, but in brief: Significant LSI-11 based system with bitmapped graphics, perhaps best known for it's use as a platform for the UCSD p-System. No connection to the seller. Was tempted, but can't really justify it given some other upcoming expenses. But they sound like pretty neat systems to mess about with... See http://www.threedee.com/jcm/terak/ for details and other links. --S.

17 years, 8 months

OT: Microsoft crazy academic deal

by korpela＠ssl.berkeley.edu

Funny, but OpenOffice is still free. Eric On Wed, Aug 20, 2008 at 4:42 PM, tonym <tonym at compusource.net> wrote: > Office Ultimate Edition for $59.95. This has > everything in it, I think retail is like $500-600.

17 years, 8 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