test-drb February 2021

test-drb@ccmp.vtda.org

113 participants
93 discussions

by nw.johnson＠ieee.org

Has anybody got a DCV54 that they are using? I am trying to get one working with David Gasswein's mfm board and having no luck. The controller is working fine with a standard floppy as an RX33, even boots the MicroVAX from it.? But on-board diagnostics cannot format or even recognise the mfm board as a winchester. Just got the scope out today and found that the drive select lines are being terminated OK on the mfm board, bit the controller is not even dropping drive select. (Yes I have tried new cables) Problem is I don't have anything old enough to test the mfm boards with other than the Plessey controlelr! I'm thinking there must be some on-board config that I am missing on the controller. - It has never had a real mfm drive connected to it. Any help appreciated, Nigel -- Nigel Johnson, MSc., MIEEE, MCSE VE3ID/G4AJQ/VA3MCU Amateur Radio, the origin of the open-source concept! Skype: TILBURY2591 nw.johnson at ieee.org

5 years

Digitalker 54104 IC

by couryhouse＠aol.com

Bill...this just? struck a memory I think I have a Radioshack Digitalker in a packaging? but recall it being just one large chip...? Ed #??? SMECC On Saturday, February 13, 2021 Bill Gunshannon via cctalk <bill.gunshannon at hotmail.com; cctalk at classiccmp.org> wrote: On 2/12/21 6:09 PM, Ethan Dicks via cctalk wrote: > On Fri, Feb 12, 2021 at 6:01 PM Jim Brain via cctalk > <cctalk at classiccmp.org> wrote: >> But, I'm sad because no one either has one nor can help me test this >> one.? So, I cannot enjoy the thrill of making it say inappropriate stuff :-( > > I have several vintage speech ICs, but not that one. > I do as well.? I have the Radio Shack "Voice Synthesizer IC Set" sitting on the desk in front of me right now. bill

5 years

Wanted: Info on Optisys/Optidisk WORM file system

by cclist＠sydex.com

I have a bunch of Panasonic/Matsushita 470/940 MB phase-change WORM discs here--and the appropriate drive (Panasonic LF-5010 SCSI-2) to read them. Unlike CD-R media, however, the format of these discs is not anything standard--they were essentially treated as hard disks. So, adding a file involves copying the directory and then adding the file information to the copy. The same applies, of course, for file deletion. If the drive tries to read a (1,024 byte) sector that hasn't been written to, it will get an error after a number of retries. I should emphasize that this drive is *not* fast--throughput seems to be on the order of a floppy disk. I can probably (with a bit of head-scratching) figure out the methodology behind this system, but I'm giving a shout-out to see if this rings any bells. Phase-change WORM did not enjoy a long life in the world, being superseded by rewritable media (both CD-RW and MO). As a point of reference, here's the data from sector 1 of a sample disc (Sector 0 is not used): > 00000400 04 0d 04 16 00 0f 0a fe 02 00 20 03 00 03 48 47 |.......... ...HG| > 00000410 49 42 32 2e 31 31 2d 30 33 2e 30 30 43 72 65 61 |IB2.11-03.00Crea| > 00000420 74 65 64 3a 20 54 68 72 20 32 32 20 41 70 72 20 |ted: Thr 22 Apr | > 00000430 31 39 39 33 20 20 20 20 20 31 35 3a 20 32 2e 32 |1993 15: 2.2| > 00000440 38 3a 35 31 20 20 20 20 4f 70 74 69 73 79 73 20 |8:51 Optisys | > 00000450 4f 70 74 69 44 69 73 6b 20 28 43 29 20 43 6f 70 |OptiDisk (C) Cop| > 00000460 79 72 69 67 68 74 20 31 39 38 37 20 2d 20 31 39 |yright 1987 - 19| > 00000470 39 31 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |91 | > 00000480 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | If nothing turns up in the community, I'll work out the format and make details available (as I understand them). TIA --Chuck

5 years

Digitalker 54104 IC

by couryhouse＠aol.com

Most challanging was to figure out to make it say naughty things... and once you did? how it almost caused havoc in AZ On Tuesday, February 9, 2021 Jim Brain via cctalk <brain at jbrain.com; cctalk at classiccmp.org> wrote: I suspect the answer to question #1 is no, but thought I would ask. 1) Anyone happen to have a known working Digitalker 54104 IC they are looking to trade for some cash that does not involve me selling an arm or a leg :-)? 2) Barring that, anyone have a known working Digitalker-based unit that might be able to pop in a suspected non working Digitalker IC and test? I have a Jameco (yep, the parts firm) manufactured Digitalker unit here called the JE-520 that is my original unit.? It suffered some ROM bit rot long ago and was not working, but I acquired the ROMs a while back to repair the unit. Now, though, as I pull it out for another project, it seems to be misbehaving.? It's like "address bit 1" on the input commands is acting up.? For instance, word 48 is "zero", and 49 is "one", but zero will be followed by "three" and then "zero" and then "three" as one sends values 48,49,50,51 to the unit.? I'm working to confirm the bit 1 on the cable to the PC is not bad, but initial efforts point to it being the IC. Jim -- Jim Brain brain at jbrain.com www.jbrain.com

5 years

Mystery (unusual) 1973 terminal

by jules.richardson99＠gmail.com

Hi all, Hopefully the following link works, but someone over on one of the Facebook vintage groups has this oddball terminal from 1973 that they've been looking for any information on: https://drive.google.com/drive/folders/1-2uEFbi3OKBYr06y6yHnygDiLMtw2Qkj ... it's somewhat unconventional in that half the CRT is hidden from view within the machine, i.e. it only actually displays the top half of the display to the user - I've no idea if that's because it had a specific application where space was limited, or if it was simply that memory at the time was horribly expensive and so it was designed to only use a few lines (I know some vendors did that, although I think they typically presented the whole CRT and at least had the option of RAM upgrade to more lines). The blower assembly seems a little on the homebrew side, but on the other hand the PCBs and case construction make it seem like a professional product. The owner says the only label anywhere on the thing is the one on the CRT saying "Mfd in Japan for Conrac", but that's presumably just the CRT itself and not the entire machine. I don't believe there's anything resembling a microprocessor in the system, it's all just TTL logic (the large white ceramic IC is an ACIA). Oh, I believe the owner's in Canada, so it may be it was made there and never exported to other parts of the world. cheers Jules

5 years, 1 month

Mystery DEC cartridge tape drive

by aek＠bitsavers.org

This is a mystery. What DEC system used a CDC Sentinel DC300 cartridge tape drive? https://www.ebay.com/itm/Vintage-Computer-DEC-BY5A5-E-Tape-Drive-77-014320/…

5 years, 1 month

One more thing to fix... HP9000/380 power supply

by ce.murillosanchez＠gmail.com

This decade seems to have increased the number of failing things in such a way that the "to be repaired" backlog is growing much faster than I can get to diminish it. Argh.? A month ago my trusty HP9000/380 ran just fine and I booted the different OS's in the SCSI and HPIB drives connected to it (this particular machine is interesting because the 9000/300 port of NetBSD was partly developed in it: it was Mike Wolfson's). Yesterday, it failed to turn on; the power supply is dead.? So I unracked the pile of drives and the computer, checked for obvious things (the fuse is fine, and nothing in the power supply is swelled up or leaking, or browned by heat; visually, it looks new; the HV caps seem to hold a charge).? I need the schematics for the power supply (at least the output connector; I can work my way back from that)? and also those for the backplane in this hp9000/380.? A preliminary search at bitsavers and elsewhere did not help.? Does anybody have these? In the meantime, I finally improved the mainboard (had the parts for a long while) from a 380 to a 385 by changing the clock generator, and replacing the 68040RC25 with an RC33. I ran this machine as a web server continuously for ten years in the 2000's, totally exposed.? Many tried to hack it... and failed. Another personal connection to this architecture is that I used Apollos and hp9000/300 at UW-Madison back in 1989-91.? Boy, did I crunch numbers... carlos.

5 years, 1 month

Reading ESDI disks

by mattislind＠gmail.com

What is the best way of dumping the contents of an ESDI disk? I have an original IBM Enhanced ESDI ISA controller board. Could that be used under Linux? Or NetBSD/FreeNSD? I googled but didn't find much. Is there any other way of dumping the disk contents? In theory it should be just a matter of clocking the raw data and finding the marks and extracting the data. Has anyone done something similar? /Mattis

5 years, 1 month

APL\360

by boris＠summitclinic.com

Counting in binary on ones fingers was something I first ran into at age 11 when found a book on Military Electronics in a surplus store. Everything simplified, but in computer section found binary system explained with using fingers to represent bits. That was something that I used immediately as used to count steps to various places but after 1000+ steps would often forget where I was so would increment my binary digital counter every 100 steps. At that age 1 mile was probably about 2500 steps so I my counter would have overflowed at about 40.9 miles. Also LSB was my left small finger which seems weird now but suspect that's what illustration in book showed of how to count in binary on your fingers. Found manual method easier to use than a pedometer. >I too count sheep with my fingers, but I never get past zero due to the >lack of sheep. :-) > >Tom Hunter > >On Mon, Feb 1, 2021 at 5:34 PM Tor Arntsen via cctalk <cctalk at classiccmp.org> >wrote: > > > On Sat, 30 Jan 2021 at 03:27, dwight via cctalk <cctalk at classiccmp.org> > > wrote: > > > If we'd thought about it we could count to 1023 on our fingers. > > > Dwight > > > > Some sheep herders in (IIRC) the Caucasus do, or did at least. I > > learned about that some decades ago. Counting sheep on their fingers. > > I use the system sometimes. > > > > -Tor > >

5 years, 1 month

Al Lasher's electronics closing.

by korpela＠ssl.berkeley.edu

One fewer place to obtain old stock components in the NorCal East Bay. https://www.berkeleyside.com/2020/12/03/lashers-electronics-berkeley-busine… -- Eric Korpela korpela at ssl.berkeley.edu AST:7731^29u18e3

5 years, 1 month

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test-drb February 2021