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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

3 years, 8 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

3 years, 8 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.

3 years, 8 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

3 years, 8 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

3 years, 8 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

3 years, 8 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.

3 years, 8 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.

3 years, 8 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

3 years, 8 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

3 years, 8 months

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