test-drb

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101090 discussions

PMI memory on an -11/93 (Was: Installing an operating system on an 11/83)

by jnc＠mercury.lcs.mit.edu

> From: Christian Gauger-Cosgrove > From the KDJ11-E module user's guide ... the solder-side of the CD > fingers is left unpopulated, but for the +5 and ground pins. > The only PMI compatible option then would be the KTJ11-B UNIBUS adapter. I forget how the -11/84-94 backplane is wired (it's wierd - the QBUS CD slots are bussed together in a group, they're not in pairs like an ordinary Q/CD backplane - but I forget the fine details), but how does the PMI get from the CPU to the KTJ11, then? I know on the same backplane, it supports PMI memory cards with the KDJ11-B. And speaking of the KDJ11-B, I just looked at one, and _it_ doesn't have any lands on the C/D connectors, side 2, either! Probably because the PMI only uses side 1 lands: https://gunkies.org/wiki/Private_Memory_Interconnect#Pinout Given that the KDJ11-E can do master-slave cycles through the KTJ11-B (to read UNIBUS device registers), it has to be able to do master-slave cycles on the PMI. What I don't know is whether, on a 2MB KDJ11-E, it will try and send memory reads for locations > 2MB out the PMI, or whether all reads below the UNIBUS address space (in 22-bit address terms) are sent to the local memory _only_. Someone with a 2MB KDJ11-E should try it... Noel

4 years, 3 months

Seeking paper tape punch

by jfoust＠threedee.com

At 08:24 PM 2/21/2022, Steve Malikoff via cctalk wrote: >Consumer-grade CNC stencil cutters are fine at cutting plastic sheet and should be ok with film stock. >My ptap2dxf (latest version 1.3) will produce output to cut tapes for ... Meaning the Cricut kind of device? Clever! So it works for short sections? Has anyone ever made a Cricut style cutter that has a continuous feed of tape? Why did you pick AutoCAD DXF as compared to Adobe Illustrator? At 07:02 PM 2/21/2022, Paul Koning via cctalk wrote: >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. GreenKeys mailing list Home: http://mailman.qth.net/mailman/listinfo/greenkeys Help: http://mailman.qth.net/mmfaq.htm Post: mailto:GreenKeys at mailman.qth.net They can be very helpful. They tend to focus on other non-33 teletypes. The list can be a good place to find out about people selling or giving away equipment, though. The collectors of the heavy, older, machined teletypes tend to shake their heads at the high prices and popularity of the light-duty cheaper punched-metal 33s. You might find someone giving away a bulky heavy ASR 28 that handles 5-level tape... https://www.telegramcableco.com/teletype-model-28-asr.html https://en.wikipedia.org/wiki/Teletype_Model_28 Less common to find them giving away a 33 because the computer nuts will pay $xxx to $x,xxx for them. - John

4 years, 3 months

PMI memory on an -11/93 (Was: Installing an operating system on an 11/83)

by jnc＠mercury.lcs.mit.edu

> From: Bill Gunshannon > Just wish I could get some PMI memory for that 93. ?? The KDJ11-E in the -11/93 comes with a minimum of 2MB on the CPU card. That's enough for almost 16 maximum-sized processes (assuming they aren't sharing program texts - almost double that, if they are). Does one really need more than that for vintage retro use? Besides, the on-board memory operates at full speed (same as cache memory on the KDJ11-B); even if you added PMI memory, the KDJ11-E has no cache, so it would be a _lot_ slower than the on-board memory. Noel PS: Can people _please_ trim messages they are replying to, so we don't all have to scroll down past a bunch of irrelevant drek? Thank you.

4 years, 3 months

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

4 years, 3 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

4 years, 3 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

4 years, 3 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.

4 years, 3 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.

4 years, 3 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

4 years, 3 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

4 years, 3 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

4 years, 3 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

4 years, 3 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

4 years, 3 months

Is The M9312 Boot Module Essential?

by jnc＠mercury.lcs.mit.edu

> From: Jay Jaeger > SACK turnaround capability so that the machine doesn't hang accessing > an address that doesn't respond on the UNIBUS. Umm, I think you're mixing up i) grant timeouts and ii) master-slave timeouts. All PDP-11 CPUs have master-slave timeout handling; after a short delay (10usec or so) with no SSYN (UNIBUS) or BRPLY (QBUS), they resume processing, and take an immediate trap. Most OS's (UNIX, for sure) use this when they are sizing memory. Grant timeouts are less well-documented. I think most CPUs deal with this (not receiving a SACK 'fairly quickly' in response to a grant); I think they basically just ignore t, and keep processing. (That is because there are legitimate causes for not having a grant ackknowledged; e.g. if a device is requesting an interrupt, and then just as the CPU sends out a grant, the device is reset, the device won't respond to the grant, since it's no longer trying to do an interrupt.) The 'SACK turnaround' I think is only used with system health verification; the system wants to make sure that the grant lines aren't broken anywhere. (That's because _if_ a grant line is broken, devices downstream of the break can no longer do interrupts, which generally _will_ hang the overall system, when interrupts don't work as usual.) To do this, the CPU sends an _un-requested_ grant out (on startup), and the SACK turnaround circuitry on the terminator turns it around and sends it back to the CPU; when the CPU sees that, it knows the grant line has no break. It probably caused more problems than it caught, which is my guess as to why no QBUS machine has/uses it. The -11/34 (not the /34A) has something unusual for grant timeouts, but I forget the details. I'll look it up. Noel

4 years, 3 months

Red Hat Linux 7.2 for Alpha

by me＠larbob.org

Try these: https://mirror.rqsall.com/misc/rh-alpha/7.2/ Larkin

4 years, 3 months

VAX9000 unearthed

by ioerg.hoppe＠gmail.com

Hi, my computer club c-c-g.de could acquire the remains of a VAX9000 ! The machine ran at the GWDG computing center in G?ttingen, Germany, around 1993. Parts of it were in stock of their museum for 20+ years. See lots of hires-pictures at https://c-c-g.de/fachartikel/359-vax-9000-ein-starker-exot (scroll to the bottom for a slide show). Joerg

4 years, 3 months

Is The M9312 Boot Module Essential?

by robert.jarratt＠ntlworld.com

I have a PDP-11/24. I have never got very far with it because of power supply problems which I am hopeful will be resolved soon. Looking at the technical manual, it describes an M9312 bootstrap/terminator module. The machine did not come with one of these. I am not sure how the machine could have been useful without it. It did work briefly before the PSU failed and I remember getting a console prompt. So, is the M9312 essential to ever get this machine to boot up an operating system? Thanks Rob

4 years, 3 months

DEC AXV11-C analog board

by dj.taylor4＠comcast.net

I have one of these and would like to use it, however it appears to only partially work.? Here is what I have found that works and what doesn't: 1. CSR and DBR are present and operational. 2. Jumpers set to 'factory'. 3. D/A portion works, can deposit codes in ODT and see voltages out on DAC pins that change depending on the octal value deposited in CSR+4 or +6. 4. A/D portion returns full scale code, either 3777 (2's compliment) or 7777 (offset binary) whether in the input is open or shorted to gnd. I think the problem is that the A/D inputs are not exactly protected and damage has occurred to this portion in the past. Does anyone have any info on the A/D module?? Who made it?? Can you open it up?? Does XXDP have a test for this? Doug

4 years, 3 months

Free Stuff - Pleasanton, Calif.

by bpettitx＠comcast.net

I'm downsizing. Have to get rid of everything. The driveway is filled systems test equipment, components, parts, books, etc. Several thousand TTL chips prototyping boards. Come out and take what you. Junk Bees will be here on Tuesday for what is left. Call 925-998-9968 for directions.

4 years, 3 months

Is The M9312 Boot Module Essential?

by jnc＠mercury.lcs.mit.edu

> From: Rob Jarratt > is the M9312 essential to ever get this machine to boot up an operating > system? Interesting question. I don't have my -11/24 running yet, so this reply is theoretical, not tried in practice (and as we all know, the difference between theory and practice is even larger in practice than it is in theory), but here goes. The M9312 basically provides two things: 1) UNIBUS termination, and 2) boostrap ROM. To further subdivide the former, it provides 1A) analog termination (i.e. a resistance at the end of a transmission line that prevents reflections of signals passing down the otherwise un-terminated transmission lines of the bus), 1B) pullups (so those transmission lines normally float at roughly 3V, unless actively driven by one of the boards plugged into the bus) and 1C) 'SACK turnaround' (a start-up 'safety check' where an un-requested - and thus 'un-grabbed' by any device - bus grant from the CPU on start-up is 'turned around' by the terminator; this verifies that the grant lines are un-broken between the CPU and the terminator - e.g. by someone forgetting to plug in a grant jumper). 1A is not _absolutely_ necessary; this can be seen in small QBUS systems (the QBUS is, at the analog level, sort of identical to the UNIBUS; this an be seen in the use of the same transceiver chips, such as 8641's, on both) which can get away without 1A in small configurations. Whether it's needed on your -11/24 is hard to predict, theoretically; the easiest thing is to just try it and see. Note: it may 'work' without it, but not be as _reliable_ as with it. 1B _is_ necessary, but can be provided anywhere on the bus; most UNIBUS/QBUS CPUs have it built in, and so does the KDF11-U of the -11/24: see pg. of MP01028. 1C is required by _some_ UNIBUS CPUs (ISTR that the -11/04 won't run without it), but the KDF11's in general don't; e.g. the -11/23 definitely runs without it. The KDF11-U might have outboard circuitry to require it, but I'm too lazy to grovel over the prints to see. Easiest to just try it and see. For 2, it all depends on what you're booting from. E.g. the RK11 has a simple enough bootstrap that you can just enter it manually (although it gets old after a while - I remember re-'programming' (think 'soldering iron' :-) a castoff BM-792 someone gave us for our -11/40 so I wouldn't have to). But if you're loading it over the console serial line, e.g. with PDP11GUI, you don't need any ROM bootstrap - the built in console ODT will be enough. You can also load a bootstrap that way; I was booting off the QSIC RK11 with a boostrap loaded over the console serial line; that was faster than the bootstrap in the BDV11. This requires finding - or writing - a bootstrap, which for later DEC mass storage controllers is not trivial. YMMV. TLDR version - probably not! Noel

4 years, 3 months

KK11-A cache for -11/34A on eBait

by jnc＠mercury.lcs.mit.edu

Anyone want a KK11-A: https://www.ebay.com/itm/275173894774 US$200 sounds like a lot, I know, but KK11-A'S and FP11-A's are going for that much; an FP11-A just went for US$250. And KK11-A's are rare; this is he first one in a while. Noel

4 years, 3 months

Is The M9312 Boot Module Essential?

by jnc＠mercury.lcs.mit.edu

> From: Rob Jarratt > I suspect some of the other cards that were in the machine might do the > necessary termination stuff. Different answers for each part of the functionality. 1A and 1C fundamentally have be at the end of the bus, physically. So, unlikely; since _other_ cards aren't, generally, designed to go there. 1B could be anywhere, but I've basically never seen anything but a CPU or a terminator with 1B functionality - probably in part because the same physical components uually do both 1A and 1B. (Oddball exception: M981 UNIBUS jumper, in the -11/40 - but that's 'sort of' part of the CPU.) 2, yes. E.g. the KT24 UNIBUS map has sockets to hold bootstrap PROMs. (Compatible with the M9312's.) Others, too; e.g. the KTJ11-B UNIBUS adapter (although that is not seen in an -11/24). Maybe others, but I can't recall off the top of my head. Noel

4 years, 3 months

Testing H745 Regulators

by robert.jarratt＠ntlworld.com

I am trying to test a couple of H745 regulators with a DC bench PSU and I am having some problems with testing them. My bench PSU is a twin unit so I can supply the +15V required as well as the "AC" input using 20VDC from the other half of the bench PSU. The problem is that I don't think the bench PSU can supply enough startup current to allow the regulator to run. It can only supply 5A max. I have seen with the H744s that if I put too big a load on them, then they can't start because of the heavy startup current required. I can start them with a lower load and then add load once the regulator is running without breaching the current limit of the PSU. With the H745s I have tried reducing the load to see if I can get them to start, but a 10R load appears to be too much and the regulators draw the full 5A without outputting -15V. I have two H745s, both exhibit the same behaviour. I suppose they could both have the same fault, but I am inclined to think that perhaps they need a higher startup current than I can supply. Can anyone confirm this? Thanks Rob

4 years, 3 months

ID these DEC floppy disks

by cz＠alembic.crystel.com

Hey all! While going through floppies I found these and was wondering what they were. Only clue in Google was someone asking in 1997 same thing. BL-T540B-M1 CZUFDB1 USER TESTS BL-T541B-M1 CZXD1B1 FIELD SERVICE TESTS 1 BL-T542B-MC CZXD2B0 FIELD SERVICE TESTS 2 BL-T565B-MC CZXD3B0 FIELD SERVICE TESTS 3 BL-T583B-MC CZXD4B0 FIELD SERVICE TESTS 4 Any ideas? The first one does not have a write protect tab, the others do. There is also one other disk I found CZMX4E0 Micro 11 Maint RX50 4 On this one the write protect flag was torn off (was on from factory and removed) C

4 years, 3 months

HP 2100S Power Supply Disassembly Tips

by derschjo＠gmail.com

Hey all -- I've had this HP 2100S mini sitting on the bench for a bit, waiting, and I wanted to go through the power supply and test/reform the capacitors this past weekend. The processor service docs cover getting the supply out (which is slightly cumbersome) and I have that step done. But neither the processor docs nor the power supply service docs seem to cover how one disassembles the supply itself. (Has a really thorough guide to how the thing works though, that I'm hoping I won't actually have to use anytime soon.) There are a lot of parts in this unit, and I'm not seeing a method to the madness. The capacitors are fairly easy to *get to* but actually removing them for testing / replacement seems to be another matter entirely. Anyone out there done this before and have any advice? Thanks! - Josh

4 years, 3 months

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