test-drb February 2022

test-drb@ccmp.vtda.org

99 participants
82 discussions

Installing an operating system on an 11/83

by rodsmallwood52＠btinternet.com

Hi ? I have built an 11/83 in a BA23 box. ? It has a KDJ-11B, 2mB PMI memory, an RQDX3 with an RX50 attached, Plus a CMD CQD 220A Disk controller with a digital RH18A 2Gig SCSI drive attached. Diag sees drive as RA82. It boots and runs the diag disk and XXDP+ just fine. I do not have install distributions for any of the 11/83 operating systems. Daily driver system is a Windows 10 PC. So how do I install an operating system? Suggestions please. Thanks Rod

2 years, 10 months

Seeking paper tape punch

by fedorkow＠mit.edu

[apologies if this is a dup, but I didn't see it coming back in any of the cctalk digests] Greetings CC-Talk, ? I've been working on a low-budget project to help to introduce students to history of computing through material we have from MIT's 1950's Whirlwind project.? The activity would have more of a hands-on feel if we could use actual paper tape. ? A simple reader is easy enough, but a punch is a bit harder.? We don't need anything "authentic", or fast, or high performance, just something fairly reliable. ?? If anyone can suggest where to find such a machine, could you let me know?? Fanuc PPR, GNT 4601/4604, and the DSI NC-2400 have been cited as possible candidates, but I don't see anything that looks like a good match on ebay. ? Thanks! /guy fedorkow

2 years, 10 months

Seeking paper tape punch

by paulkoning＠comcast.net

> On Feb 21, 2022, at 6:07 PM, Guy Fedorkow <fedorkow at mit.edu> wrote: > > hi Paul, > Yes, I should have said -- I'm looking for a machine that can punch under control of a computer. > Whirlwind actually used seven-bit Flexowriters for reading and punching (along with a high-speed reader later on), but I think it would be even harder to find fresh seven-level tape even if a seven bit machine turned up. > I actually have been using a BRPE on loan from another contributor to this list, but it's time to return the unit, so I've started to look for alternatives. > I assume something like an ASR-33 would do the trick, although a machine without keyboard and printer might have fewer moving parts to go wrong. But I don't see many plausible choices on ebay. > If anyone can suggest other sources, I'll poke around The nice thing about an ASR33 (or other hardcopy terminal with reader/punch like a TT model 15) is that you can interface them to a computer rather easily, just hook up a UART with appropriate driver/receiver circuitry. RS232 to 20 mA (or 60mA for a Model 15) isn't totally trivial but it certainly is no big deal. And those slow machines actually have the nice benefit that it's easy for people to see the action, and to get some understanding at a gut level of how slow computers were in those days. I understand there is a group called "Green keys" -- ham radio operators who use old "teletype" machines -- which in that community means wny sort of keyboard telex-type machine, not necessarily made by Teletype Co. though US ones often are. 5 bit machines are common in that crowd, some 8 bit machines also appear. I haven't participated, but I would think that you might find pointers to options there. As for 7 bit tape media: I found out in the past year or so that there actually was such a thing as paper tape of width designed for 7 tracks, but a lot of "7 bit" paper tape work actually used 1 inch wide tape, i.e., what is normally considered 8 bit tape. For example, the Flexowriters on which I did my first programming at TU Eindhoven used a 7-bit code but on 8 bit tape. paul

2 years, 10 months

VAX9000 unearthed

by mark.kahrs＠gmail.com

I heard Butler Lampson once exclaim that ECL design was in some ways easier than TTL. If you terminated every line, you get controlled impedances with controlled edges. This was the design philosophy for the Dorado.

2 years, 10 months

More VT52 HV

by fritzm＠fritzm.org

So, having pulled the CRT now , I was surprised to see that the ground braids seem to be held against the aquadag by only the pressure from a couple foam blocks! In my unit these aged foams are deformed and brittle. This would seem a good thing to add to the check list for looking at these? I wonder if this explains why many of these I encountered back in the day in university terminal rooms and such were suffering from HV ?snaps?? I had always assumed it was just dust / grime / spilled cokes? :-) Also, after a closer look, I?m surmising the red goo around the anode cap to be dielectric grease put there on purpose, and not degradation of the cap itself. ?FritzM.

2 years, 10 months

rotron caravel fan used in DEC and other cabinets

by useddec＠gmail.com

Does anyone have a video or printed procedure they can send me or point me somewhere that could help? Thanks, Paul

2 years, 10 months

rotron caravel fan used in DEC and other cabinets

by jnc＠mercury.lcs.mit.edu

> From: Vincent Slyngstad > I had to replace one of those recently Where did you source the replacement? I need a few. Thanks! Noel

2 years, 10 months

Is The M9312 Boot Module Essential?

by jnc＠mercury.lcs.mit.edu

> Neither the KD11-E nor the KD11-EA has built-in termination and pull-ups > ... I haven't yet checked, but it may be the only PDP-11 CPU of which > that is true Also the KD11-D of the -11/04. Noel

2 years, 10 months

Is The M9312 Boot Module Essential?

by jnc＠mercury.lcs.mit.edu

So, I've made what I think is a significant discovery about the -11/34: > 1B _is_ necessary, but can be provided anywhere on the bus; most > UNIBUS/QBUS CPU [pullups] have it built in I was wrong. Neither the KD11-E nor the KD11-EA has built-in termination and pull-ups (those are both done with one set of components). I haven't yet checked, but it may be the only PDP-11 CPU of which that is true Without _something_ doing the latter of the above, the UNIBUS won't function at all. (The UNIBUS signal lines mostly operate as negative-logic wired-OR; the pull-ups float it high for '0', and any board pulls it low to send a '1'. No pull-ups, then..) This is almost certainly the reason that the manual calls for the use of either an M9301 ROM or M9312 ROM (which include bus termination) at the start of their UNIBUS, in slot 3 or 4 of the CPU's backplane. (The M7859 of the KY11-LB doesn't have pull-ups either; so in a system with a set of KD11-E/EA cards, and a KY11-B, and nothing else, the KY11-B won't be able to examine UNIBUS locations - even though in a system with _just_ a KY11-B, and one of M9301/M9302/M9312, and NO KD11-E/EA, the KY11-B _can_ do UNIBUS operations.) A system with just an M9302, and no M9301/M9312, will _probably_ work, even though the UNIBUS is only terminated at one end (see my previous post, about QBUS termination on one end only); the M9302 will provide the pull-ups needed for the UNIBUS to function (above). I have also made a number of interesting discoveries about the SACK turnaround; I'll put them in a reply to Fritz's message. Noel

2 years, 10 months

SGI Indigo keyboard / mouse / converter wanted

by jules.richardson99＠gmail.com

Hi all, A friend of mine has just acquired an Indigo (R4k with XZ graphics option), but of course it's the usual story and the keyboard/rodent had been lost. In absence of the genuine items they'd still be happy with a USB converter (at least for the time being), but it seems those are difficult to come by at present, too. Does anyone happen to have a surplus converter suitable for these machines, and/or keyboard/rodent? (according to sgistuff keyboard is p/n 9500801 and mouse p/n 9150800) [side note: they mentioned a USB converter, but I'm pretty sure years ago someone had implemented an adapter to PC-friendly PS/2 parts, too. I'm sure something like would do the trick, too] thanks, Jules

2 years, 10 months

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test-drb February 2022