test-drb October 2021

test-drb@ccmp.vtda.org

100 participants
69 discussions

by c.murray.mccullough＠gmail.com

To my knowledge the Linux kernel was released to the public 30 years ago around this time. My dear friend swears by it and will never go back to Windows even though WIN 11 is much more secure than previous Windows versions. Prior to Linux there were other much-earlier operating systems for 8-bit and 16-bit machines we classic computer users could use. For emulators now we have a choice but do they work better in Linux or Windows? Happy computing. Murray ?

3 years, 1 month

Looking for manual for MDB MLSI-LP11

by g4ajq1＠gmail.com

Does anybody have any sources other than bitsavers and vcf? cheers, Nigel

3 years, 1 month

Dec DMX11--What was it?

by cz＠alembic.crystel.com

Anyone know about the Dec DMX11? It was apparently a 64 serial line Mux that plugged into pdp11 Unibus systems and had a fair amount of both intelligence and insanity on board. Reason is I'm looking into some old documentation about late 1970's Tote systems for Asian race tracks and the system they were building was beyond astronomical in terms of insanity. (As in an 8 way pdp11/70 system cluster, with 11/04's running these DMX11's to hundreds of terminals)

3 years, 1 month

: FTGH Various DLT and 4mm DAT Drives - Midlands UK

by james＠attfield.co.uk

============================================================================ ===================== Message: 1 From: Liam Proven <lproven at gmail.com> Subject: Re: FTGH Various DLT and 4mm DAT Drives - Midlands UK On Fri, 22 Oct 2021 at 06:38, James Attfield via cctalk <cctalk at classiccmp.org> wrote: > > I?m having a general clear out and the following are free for the collection rather than they go in the skip/dumpster. You haven't said where you are. Message: 2 From: Grant Taylor <cctalk at gtaylor.tnetconsulting.net> Subject: Re: FTGH Various DLT and 4mm DAT Drives - Midlands UK On 10/22/21 3:41 PM, Liam Proven via cctalk wrote: > You haven't said where you are. Per the subject, Midlands UK. I don't know how big of an area that is, but I do know that it's way out of the way for me to go pick up. ============================================================================ ===================== Apologies if I did not make it clear, I am located about 12 miles SSW of Birmingham, United Kingdom. My 3W location is tilt.custom.glitz I have also checked and tested the following: Apple Powermac G4/768Mb/74Gb OSX 10.4 Apple Powermac G4 Mirror Door Dual 867MHz CPU/1.75Gb/74Gb OSX 10.5 Both in very good condition and running very nicely with OSX installed, working DVD and Ethernet. Both are lovely machines, not keen to do FTGH but would entertain reasonable offers to get them a good and loving home. Also available but as yet untested (working when racked) a Dell Prolinea 575e and an HP Vectra VE. The Dell has what you might term a proper FDC. Those who are into FDD transfers will know what I mean. Both of these are FTGH. Sorry for those who are outside of the UK, I know how it feels. Having said that, I would trade all of this (including the Powermacs) for a working Cromemco Z2D or CS3 chassis. I would even consider a Cromemco System-1 chassis. James

3 years, 1 month

Looking for info on memory

by jnc＠mercury.lcs.mit.edu

> From: Nigel Johnson Ham > an 11/23 will not work without bank zero memory It depends on what you mean by 'work'. If you mean 'ODT does not operate correctly', or 'the CPU won't run', I can assure you that neither of those is correct. Here is a recorded log from a session earlier today on a system here next to my desktop: it contains a KDF11-A (in slot 1Left of a Q-Q backplane) and a console DLV11-J (in slot 1Right), and no other cards: ^@^@ 000000 @777560/000000 @777564/000000 777566/000000 777570/? @777640/177777 777 @/000777 @777640G Cmd: 177640 @^@^@ As you can see, ODT is working,and the console registers are all responding OK. The thing at the bottom is that hack of putting a small program in the PARs (UIPAR0, in this case). The "Cmd:" prompt is where I told my console program to send a 'break' down the serial line to the -11, stopping the CPU. (The 'run' light had been on, after the "777640G".) (Note: The PAR hack doesn't work in J-11 CPUs; they won't do instruction fetches from PARs.) To confirm that I'm not BSing you, can someone else on the list please do this on their KDF11-A, and confirm that it produces the results I show about? Thanks. > All I get is output of 173000 and the no ability to input. If that's with just a non-LSI11 CPU card and the console serial line, the machine has a problem. As you can see above (the "777560/", etc were my type-in), you should be able to talk to ODT on a KDF11 (and I tried a KDJ11 yesterday, it worked too). (I don't recall if the LSI-11 types _anything_ when started with no working memory at 0; if anyone wants to know, I can fairly easily try it, I have a bunch of working LDI-11's, both quad and dual cards). Noel

3 years, 1 month

Looking for info on memory

by jnc＠mercury.lcs.mit.edu

> From: Nigel Johnson > I will wait with bated breath! First things first; did you get either/both CPU's running ODT OK in a system containing just i) the CPU card and ii) the console serial interface? Noel

3 years, 1 month

Atari ST documents

by van.snyder＠sbcglobal.net

I sold my Atari ST some time ago. Today, I found some old documents relating to it. Not from Atari. 1. Zubair Z-Ram 3-D/4MEG add-on memory board (plugs into the glue socket). 2. Atari CHKDISK3 Documentation (April 22, 1990) 3. Atari GEMDOS Reference Manual (April 4, 1986) 4. Weirdly, the circuit diagrams for the IBM AT 5.25" double-sided diskette drive in the same folder. 5. Quick reference sheet for microEmacs. They're yours for the price of a PDF shipping label for a 14oz 10"x12" envelope. Van Snyder van.snyder at sbcglobal.net 1.

3 years, 2 months

FTGH Various DLT and 4mm DAT Drives - Midlands UK

by james.attfield＠icloud.com

I?m having a general clear out and the following are free for the collection rather than they go in the skip/dumpster. Most if not all were working when put away but I can?t offer any guarantees. Preference will be given to anyone who will take all of them. Photos are available if required, if I get time to ge a drive on line and can erase tapes quite a few will be available as well. - Compaq 20/40GB in chassis - HP Surestore DLT40 in chassis (20/40GB?) - Digital DLT in chassis (35/70GB) - Compaq 35/70GB in chassis - DLT 35/70GB in chassis (same drive as in the Digital chassis) - DLT 35/70GB bare drive (same drive as in Digital chassis) - 4mm DAT in chassis (probably 4/8GB) - 4mm DAT, 5.25? spacers, no chassis, (probably 4/8GB) - 4mm DAT, 5.25? spacers, no chassis, (probably 4/8GB) - 4mm DAT, no spacers, no chassis, (probably 4/8GB) They won?t be around long so with apologies, if you have any interest, please don?t delay. Let me kow here then we can take comms off line. Sorry, can?t ship. ? James --- Credentials Loves Cromemco, loves Unix, loves DeSmet C. Hand built an original IMSAI 8080, Nascom I and II, resurrected a TU-ART from the dead, owned one of the first EXIDY Sorcerers in the UK, ran Byte Shop/Computerland (Birmingham).

3 years, 2 months

Power supply power-up and power-down sequencing: how did it work?

by stepleton＠gmail.com

Hi cctalk, I asked this question over on vcfed, but in the spirit of knowing more (and avoiding silly, costly mistakes) I thought I'd ask again here. I hope this is okay --- I think there must be a lot of community expertise to draw from, and not everyone is in the same forums. After seeing CuriousMarc's horror film about the killer transistor that zapped the guts of his HP9825T, I've been working for some time on a solid-state DC power supply monitor device that will chop all power to logic if there's ever any excursion above or below critical voltage thresholds on any power supply channel. I've been pretty successful in the development so far and have a gizmo that accomplishes the basic goal, even if it's not going to win any industrial design awards. It's not a crowbar circuit: each voltage channel passes through a substantial driver IC that can switch the power right off. My device can detect and react to anomalies very quickly. But then you browse through old DRAM datasheets and see warnings like these: "Vbb must be applied prior to Vcc and Vdd. Vbb must also be the last power supply switched off." "Forward biasing this supply [that is, Vbb] with respect to Vss will destroy the memory device." And so even though my device is fast, it's possible that when it's slamming the doors shut, there's a split second where -5V is off and +12V is still on, or even the chance of a Vbb-Vss forward-bias "blip", who knows? Of course you can measure whether this is happening, but it's difficult to know how meaningful that will be: maybe a computer that loads the voltage rails differently will have different behaviour, and remember, the case you really care about is when a power supply behaves abnormally! System characterisation is hard... Anyway, my question is: what did hardware designers in the '70s do to satisfy specified power supply requirements for the chips they were using? The conversation so far on vcfed has two remarks: one observing that a lot of folks just didn't worry about it, and one pointing out an anti Vbb>Vss gimmick in the PSU for the Nascom kit computer involving a ladder of protective diodes between each of the rails: (-12V) ---->|---- (-5V) ---->|---- (0V) ---->|---- (+5V) ---->|---- (+12V) I noticed a similar pattern in a few other PSU schematics, but usually only for the negative channels. Were there any other common tricks? How serious was the danger of getting it wrong? How fast could you fry your DRAM if you did? Thanks for any insight, --Tom

3 years, 2 months

Looking for info on memory

by g4ajq1＠gmail.com

I am trying to bring up an 11/23 system in a BA23 box, and the only memory i have is an obscure Plessey one. The only identification is the p/n 705920 with dash-100 in white ink. By counting the chips I make it 4MB, but it does not respond. Since it takes the full 22-bit memory space I can't see how any jumpers would change its accessibility. Does anybody have a manual? any help appreciated, Nigel Johnson

3 years, 2 months

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test-drb October 2021