#umdpdp12 — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #umdpdp12, aggregated by home.social.
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My student, Zach, got the famous Whetstone floating-point benchmark running in FORTRAN IV on our PDP-12 (results had never been recorded for a '12 without an FPP). He also implemented the Dhrystone integer benchmark in PDP-8 assembly, which (as far as we know) has never been done before. You can read more about it here, and if you have a PDP-8 compatible machine (with or without EAE), you should be able to run his code to benchmark your system! Way to go, Zach! https://forum.vcfed.org/index.php?threads/pdp-8-and-pdp-12-and-dhrystone-and-whetstone.1253367/ #pdp12 #pdp #retrocomputing #umdpdp12 #pdp8
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My student, Zach, got the famous Whetstone floating-point benchmark running in FORTRAN IV on our PDP-12 (results had never been recorded for a '12 without an FPP). He also implemented the Dhrystone integer benchmark in PDP-8 assembly, which (as far as we know) has never been done before. You can read more about it here, and if you have a PDP-8 compatible machine (with or without EAE), you should be able to run his code to benchmark your system! Way to go, Zach! https://forum.vcfed.org/index.php?threads/pdp-8-and-pdp-12-and-dhrystone-and-whetstone.1253367/ #pdp12 #pdp #retrocomputing #umdpdp12 #pdp8
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My student, Zach, has been working to debug why our bottom tape unit has been misbehaving. We are fairly certain that the issue is a short in the interface cable between the top and bottom units, because the problem appears on whatever unit is on the end of the daisy chain. Stay tuned. But in the process of monkeying with it, there was a period of time where they both worked just fine! #dec #pdp12 #pdp #retrocomputing #vintagecomputing #umdpdp12
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My student, Zach, has been working to debug why our bottom tape unit has been misbehaving. We are fairly certain that the issue is a short in the interface cable between the top and bottom units, because the problem appears on whatever unit is on the end of the daisy chain. Stay tuned. But in the process of monkeying with it, there was a period of time where they both worked just fine! #dec #pdp12 #pdp #retrocomputing #vintagecomputing #umdpdp12
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Hi all, we did our annual PDP-12 demo in Dr. Ted Pedersen's architecture class on Tuesday, and it went really well.
In cleaning up / reorganizing after showing off our artifacts, I realized that we have something that I haven't seen on @bitsavers, but I maybe just didn't know where to look. It's a big poster of PDP-12 instructions -- it's kind of like the pocket reference in poster format. It is about 9.5x30 inches (24x76 cm). I scanned it in two pieces on the office machine and stitched it together with GIMP. I'll try to make a PDF version with OCR text. @bitsavers #vintagecomputing #retrocomputing #pdp12 #pdp #dec #umdpdp12
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Hi all, we did our annual PDP-12 demo in Dr. Ted Pedersen's architecture class on Tuesday, and it went really well.
In cleaning up / reorganizing after showing off our artifacts, I realized that we have something that I haven't seen on @bitsavers, but I maybe just didn't know where to look. It's a big poster of PDP-12 instructions -- it's kind of like the pocket reference in poster format. It is about 9.5x30 inches (24x76 cm). I scanned it in two pieces on the office machine and stitched it together with GIMP. I'll try to make a PDF version with OCR text. @bitsavers #vintagecomputing #retrocomputing #pdp12 #pdp #dec #umdpdp12
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Today was PDP-12 demo day! #vintagecomputing #retrocomputing #pdp #pdp12 #umdpdp12
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Today was PDP-12 demo day! #vintagecomputing #retrocomputing #pdp #pdp12 #umdpdp12
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A TU-55 LINCtape drive from a PDP-12 in action. #vintagecomputing #retrocomputing #pdp #pdp12 #umdpdp12
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A TU-55 LINCtape drive from a PDP-12 in action. #vintagecomputing #retrocomputing #pdp #pdp12 #umdpdp12
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From the DEC OS/8 Handbook https://bitsavers.org/pdf/dec/pdp8/os8/OS8_Handbook_Apr1974.pdf (1974). Personally, I think they're really underselling themselves.
#dec #pdp #umdpdp12 #vintagecomputing #retrocomputing #basic
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From the DEC OS/8 Handbook https://bitsavers.org/pdf/dec/pdp8/os8/OS8_Handbook_Apr1974.pdf (1974). Personally, I think they're really underselling themselves.
#dec #pdp #umdpdp12 #vintagecomputing #retrocomputing #basic
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Our PDP-12 (#435) is able to read tapes (but not yet write them). This OS/8 tape is close to 50 years old and still reads well. Here we use the TYPE command to print a long listing stored on multiple tape blocks. LINC and DECtape was able to be used as random access storage (like a disk). The block numbers were written forwards and backwards on the tape so that they could be read regardless of the motor's direction!
In this video, we have a tape mounted on the top drive and have already booted. Zach requests to print the file to the (virtual) teletype, and the blocks of the file are read in sequence.
#umdpdp12 #dec #pdp #pdp12 #retrocomputing #vintagecomputing
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Our PDP-12 (#435) is able to read tapes (but not yet write them). This OS/8 tape is close to 50 years old and still reads well. Here we use the TYPE command to print a long listing stored on multiple tape blocks. LINC and DECtape was able to be used as random access storage (like a disk). The block numbers were written forwards and backwards on the tape so that they could be read regardless of the motor's direction!
In this video, we have a tape mounted on the top drive and have already booted. Zach requests to print the file to the (virtual) teletype, and the blocks of the file are read in sequence.
#umdpdp12 #dec #pdp #pdp12 #retrocomputing #vintagecomputing
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Here's a PDF for the FabriTek Model 8 Add-on Core Memory for the PDP-8 and PDP-12 -- this is the device that Vince's MM8/I memory expansion emulates (or replaces). (Thanks, Bitsavers, as always!) http://www.bitsavers.org/pdf/fabritek/model_8/400-0226-00_Model_8_PDP-8_24kCore_197401.pdf #umdpdp12 #pdp-12 #pdp-8 #pdp #dec #VintageComputing #RetroComputing
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Here's a PDF for the FabriTek Model 8 Add-on Core Memory for the PDP-8 and PDP-12 -- this is the device that Vince's MM8/I memory expansion emulates (or replaces). (Thanks, Bitsavers, as always!) http://www.bitsavers.org/pdf/fabritek/model_8/400-0226-00_Model_8_PDP-8_24kCore_197401.pdf #umdpdp12 #pdp-12 #pdp-8 #pdp #dec #VintageComputing #RetroComputing
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Today, Zach and I got Vince Slyngstad's PDP MM8/I memory expansion installed in our PDP-12! No magic smoke got out, the computer booted, and appears (from console and diagnostic checks) to have 32kW of memory! The PDP-12 only had room for 8 kW inside, but could connect to an external box that would include up to 24kW of additional core. Vince's expansion plugs into the five flip chip slots that would normally lead to the external unit. All memory hardware is on those five cards, with a six card providing an electrical connection. More soon! #umdpdp12 #pdp12 #pdp #dec #RetroComputing #VintageComputing
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Today, Zach and I got Vince Slyngstad's PDP MM8/I memory expansion installed in our PDP-12! No magic smoke got out, the computer booted, and appears (from console and diagnostic checks) to have 32kW of memory! The PDP-12 only had room for 8 kW inside, but could connect to an external box that would include up to 24kW of additional core. Vince's expansion plugs into the five flip chip slots that would normally lead to the external unit. All memory hardware is on those five cards, with a six card providing an electrical connection. More soon! #umdpdp12 #pdp12 #pdp #dec #RetroComputing #VintageComputing
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A video from the same session: #umdpdp12 #pdp #pdp12 #dec #RetroComputing #VintageComputing
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A video from the same session: #umdpdp12 #pdp #pdp12 #dec #RetroComputing #VintageComputing
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PDP-12 #435 playing Spacewar! for the first time in over two years thanks to some debugging by us and our much more experienced friends on the VCF forums.
First, we noticed that minicom was inserting CRs in front of LFs when sending paper tapes, so we switched to a different paper tape sender, and second, someone pointed out that it looked like our 2nd 4K core was not inserted correctly (two cables were backwards). Fortunately, the magic smoke didn't get out.
The machine booted up like a champ, and April and Zach got their first chance to play the original deathmatch game. 💚
#umdpdp12 #pdp12 #pdp #dec #VintageComputing #RetroComputing
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PDP-12 #435 playing Spacewar! for the first time in over two years thanks to some debugging by us and our much more experienced friends on the VCF forums.
First, we noticed that minicom was inserting CRs in front of LFs when sending paper tapes, so we switched to a different paper tape sender, and second, someone pointed out that it looked like our 2nd 4K core was not inserted correctly (two cables were backwards). Fortunately, the magic smoke didn't get out.
The machine booted up like a champ, and April and Zach got their first chance to play the original deathmatch game. 💚
#umdpdp12 #pdp12 #pdp #dec #VintageComputing #RetroComputing
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Well, our eagle-eyed and experienced friends on the VCF forums noticed something that seemed a little weird about our PDP-12... the W025 cards for Field 1 were not crossed, but were parallel like the ones for Field 0. (Seems logical, right?)
Looking at old photos showed that Field 1 used to be crossed, just like some other PDP-12s we know about.
Zach and I swapped the cards back today and...
#umdpdp12 #pdp12 #dec #pdp #RetroComputing #VintageComputing
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Well, our eagle-eyed and experienced friends on the VCF forums noticed something that seemed a little weird about our PDP-12... the W025 cards for Field 1 were not crossed, but were parallel like the ones for Field 0. (Seems logical, right?)
Looking at old photos showed that Field 1 used to be crossed, just like some other PDP-12s we know about.
Zach and I swapped the cards back today and...
#umdpdp12 #pdp12 #dec #pdp #RetroComputing #VintageComputing
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We scoped the '12, got some useful information, and did not let any magic smoke out! https://forum.vcfed.org/index.php?threads/pdp-12-435-at-the-university-of-minnesota-duluth.1241469/post-1388752 #umdpdp12 #pdp #pdp12 #dec #retrocomputing #vintagecomputing
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We scoped the '12, got some useful information, and did not let any magic smoke out! https://forum.vcfed.org/index.php?threads/pdp-12-435-at-the-university-of-minnesota-duluth.1241469/post-1388752 #umdpdp12 #pdp #pdp12 #dec #retrocomputing #vintagecomputing
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PDP-12 demo went great! #pdp12 #pdp #vintagecomputing #retrocomputing #umdpdp12
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PDP-12 demo went great! #pdp12 #pdp #vintagecomputing #retrocomputing #umdpdp12
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Giving a presentation on the PDP-12 tomorrow, so Kyle and I did a little comparison of the PDP-12 and the Google Pixel 8 Pro:
- Of course, the PDP-12 is 12-bit (0-4096) while the Pixel 8 Pro is 64-bit (0-1.84x10^19)
- PDP-12 instructions vary, but are commonly 1.6usec each. The Pixel 8 Pro has 9 cores of varying speeds, but we estimate that it is around 1,300-11,000 times faster depending on how you calculate it
- The Pixel 8 Pro has a *million times* more RAM than the PDP-12 (8GB vs. 8KB)
- If crushed into a powder, approximately 7,000 Pixel 8 Pros could fit into the space occupied by the PDP-12 (a Pixel 8 Pro occupies approximately 1/7000th the volume of the PDP-12)
- A Pixel 8 Pro costs about $1,000, while our PDP-12 would have cost approximately $400,900 in 2024 dollars (it was $54k in 1972)! (Conversely, a Pixel 8 Pro would have cost about $135 in 1972 dollars!) In other words, the Pixel 8 Pro is 400 times cheaper than the PDP-12.
- Millions of Pixel phones have been sold, to say nothing of all Android phones -- while only about ~725 PDP-12s were sold. The PDP-8, a *wildly successful* minicomputer sold only about 50k units.
#pdp12 #pdp #dec #retrocomputing #vintagecomputing #umdpdp12 -
Giving a presentation on the PDP-12 tomorrow, so Kyle and I did a little comparison of the PDP-12 and the Google Pixel 8 Pro:
- Of course, the PDP-12 is 12-bit (0-4096) while the Pixel 8 Pro is 64-bit (0-1.84x10^19)
- PDP-12 instructions vary, but are commonly 1.6usec each. The Pixel 8 Pro has 9 cores of varying speeds, but we estimate that it is around 1,300-11,000 times faster depending on how you calculate it
- The Pixel 8 Pro has a *million times* more RAM than the PDP-12 (8GB vs. 8KB)
- If crushed into a powder, approximately 7,000 Pixel 8 Pros could fit into the space occupied by the PDP-12 (a Pixel 8 Pro occupies approximately 1/7000th the volume of the PDP-12)
- A Pixel 8 Pro costs about $1,000, while our PDP-12 would have cost approximately $400,900 in 2024 dollars (it was $54k in 1972)! (Conversely, a Pixel 8 Pro would have cost about $135 in 1972 dollars!) In other words, the Pixel 8 Pro is 400 times cheaper than the PDP-12.
- Millions of Pixel phones have been sold, to say nothing of all Android phones -- while only about ~725 PDP-12s were sold. The PDP-8, a *wildly successful* minicomputer sold only about 50k units.
#pdp12 #pdp #dec #retrocomputing #vintagecomputing #umdpdp12 -
So my old friend @spacehobo wrote an implementation of Hellorld! for the PDP-12, and getting it to run was quite an adventure. How old of a friend? What's Hellorld!? How quite of an adventure was it it? Watch and learn -- you won't regret it.
(Nick also did a "takeover" of our channel and produced this video, so it is well above our standard sub-standard quality!)
#umdpdp12 #pdp12 #pdp #dec #retrocomputing #vintagecomputing #hellorld
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So my old friend @spacehobo wrote an implementation of Hellorld! for the PDP-12, and getting it to run was quite an adventure. How old of a friend? What's Hellorld!? How quite of an adventure was it it? Watch and learn -- you won't regret it.
(Nick also did a "takeover" of our channel and produced this video, so it is well above our standard sub-standard quality!)
#umdpdp12 #pdp12 #pdp #dec #retrocomputing #vintagecomputing #hellorld
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A week or two ago, we got Kaleidoscope to run on the PDP-12! We haven't found and repaired any broken flip chips. So, either all the "percussive maintenance" we've been doing in the process of testing flip chips has paid dividends, or -- more likely -- I tried to run it in 8-mode last time... it is a LINC program. Anyway, enjoy these GIFs. #umdpdp12 #pdp #pdp12 #dec #retrocomputing #vintagecomputing #minicomputer
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A week or two ago, we got Kaleidoscope to run on the PDP-12! We haven't found and repaired any broken flip chips. So, either all the "percussive maintenance" we've been doing in the process of testing flip chips has paid dividends, or -- more likely -- I tried to run it in 8-mode last time... it is a LINC program. Anyway, enjoy these GIFs. #umdpdp12 #pdp #pdp12 #dec #retrocomputing #vintagecomputing #minicomputer
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A couple weeks ago, for no apparent reason, the hits to our PDP-12 channel on YouTube went through the roof (for us). Then, as quickly as they came, they went! Oh well, glad I didn't quit my day job, and as @spacehobo pointed out -- the PDP-12 is *part* of my day job. 🤣 💚
https://www.youtube.com/playlist?list=PLHnc49MScQBBIlVIirpZ1Zjdh91U5Q6-6
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A couple weeks ago, for no apparent reason, the hits to our PDP-12 channel on YouTube went through the roof (for us). Then, as quickly as they came, they went! Oh well, glad I didn't quit my day job, and as @spacehobo pointed out -- the PDP-12 is *part* of my day job. 🤣 💚
https://www.youtube.com/playlist?list=PLHnc49MScQBBIlVIirpZ1Zjdh91U5Q6-6
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Ever wondered how to turn your 1970s-era PDP-12 minicomputer into a manual musical instrument, kinda like a really crappy theremin? Well, wonder no further! In this video, I provide the source code and performance technique information necessary to do just that! https://www.youtube.com/watch?v=HHepkRo7yRI
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Ever wondered how to turn your 1970s-era PDP-12 minicomputer into a manual musical instrument, kinda like a really crappy theremin? Well, wonder no further! In this video, I provide the source code and performance technique information necessary to do just that! https://www.youtube.com/watch?v=HHepkRo7yRI
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My friend @spacehobo saw our PDP-12 wallpaper in the background of one of our videos and wanted a downloadable one, so here's two of them in 1080p. His interest has inspired me to make higher-res versions available in multiple DEC liveries. We also have a special PDP-12 version based on the nameplate at the top of our machine, but it's not ready for the limelight. Enjoy, and stay tuned!
#umdpdp12 #pdp #dec #retrocomputing #vintagecomputing #wallpaper #pdp12
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My friend @spacehobo saw our PDP-12 wallpaper in the background of one of our videos and wanted a downloadable one, so here's two of them in 1080p. His interest has inspired me to make higher-res versions available in multiple DEC liveries. We also have a special PDP-12 version based on the nameplate at the top of our machine, but it's not ready for the limelight. Enjoy, and stay tuned!
#umdpdp12 #pdp #dec #retrocomputing #vintagecomputing #wallpaper #pdp12
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An M117E (left) and an M117C (right). The pinouts and logic are the same, but the etch (the traces) and chip layout are different. We think the rev C cards may have been put into our machine as part of a repair.
#umdpdp12 #dec #pdp12 #pdp #vintagecomputing #retrocomputing
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An M117E (left) and an M117C (right). The pinouts and logic are the same, but the etch (the traces) and chip layout are different. We think the rev C cards may have been put into our machine as part of a repair.
#umdpdp12 #dec #pdp12 #pdp #vintagecomputing #retrocomputing
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The #umdpdp12 is serial number 435. According to this 1978 document from #DEC, the total number of #pdp12 #minicomputers ever produced should be 765: https://archive.org/details/bitsavers_decBooksDE78_60225737/page/n93/mode/2up
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The #umdpdp12 is serial number 435. According to this 1978 document from #DEC, the total number of #pdp12 #minicomputers ever produced should be 765: http://s3data.computerhistory.org/pdp-1/dec.digital_1957_to_the_present_(1978).1957-1978.102630349.pdf
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I wrote a short series of help commands in #PunyInform for an #InteractiveFiction project. I wrote a short `intro` verb, a longer `help` document with the most common verbs needed to win the game, and a `stuck` verb that tells the user not to panic before advising on strategies for solving the puzzles.
I then decided to remap the StrongSub verbs over to my new StuckSub, so that it can catch anyone swearing at the game in frustration.
And yes, I included the #umdpdp12 #easteregg, where they found a command log of someone swearing at "this stupid chunk of germanium". I decided to make the help system replicate the #os8 error message in honour of this moment in #pdp12 #VintageComputing history.
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I wrote a short series of help commands in #PunyInform for an #InteractiveFiction project. I wrote a short `intro` verb, a longer `help` document with the most common verbs needed to win the game, and a `stuck` verb that tells the user not to panic before advising on strategies for solving the puzzles.
I then decided to remap the StrongSub verbs over to my new StuckSub, so that it can catch anyone swearing at the game in frustration.
And yes, I included the #umdpdp12 #easteregg, where they found a command log of someone swearing at "this stupid chunk of germanium". I decided to make the help system replicate the #os8 error message in honour of this moment in #pdp12 #VintageComputing history.
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The nameplate on our PDP-12, found inside the case. #umdpdp12 #retrocomputing #vintagecomputer #pdp #pdp12 #dec
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The nameplate on our PDP-12, found inside the case. #umdpdp12 #retrocomputing #vintagecomputer #pdp #pdp12 #dec
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OK, so where did all of this #LINC and #pdp8 stuff from this whoooole thread end up? Well, Dick Clayton from #dec explains in this short interjection at the DigiBarn event:
https://youtu.be/xT_5PcrVI9Q?t=5810
Basically Digital made a weird hybrid LINC/pdp8 system called the LINC-8, but it wasn't that great. So while he was on jury duty, he sketched out the Right Way to do it so that the system could switch between "8 mode" and "LINC mode" *in software*. The result was the #pdp12, which sold more units than all the previous LINC systems combined.
And that takes us to tonight's thread from @tastytronic, where the #umdpdp12 has just had its first successful verification tests of some of its 60-year-old flipchip cards: https://teh.entar.net/@tastytronic/109644812161500698
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OK, so where did all of this #LINC and #pdp8 stuff from this whoooole thread end up? Well, Dick Clayton from #dec explains in this short interjection at the DigiBarn event:
https://youtu.be/xT_5PcrVI9Q?t=5810
Basically Digital made a weird hybrid LINC/pdp8 system called the LINC-8, but it wasn't that great. So while he was on jury duty, he sketched out the Right Way to do it so that the system could switch between "8 mode" and "LINC mode" *in software*. The result was the #pdp12, which sold more units than all the previous LINC systems combined.
And that takes us to tonight's thread from @tastytronic, where the #umdpdp12 has just had its first successful verification tests of some of its 60-year-old flipchip cards: https://teh.entar.net/@tastytronic/109644812161500698
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Special bonus: a picture of a double-wide M706 (rev. K) teletype receiver card under test.
#umdpdp12 #RetroComputing #VintageComputing #DEC #pdp #pdp12 #FlipChip
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Special bonus: a picture of a double-wide M706 (rev. K) teletype receiver card under test.
#umdpdp12 #RetroComputing #VintageComputing #DEC #pdp #pdp12 #FlipChip
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Finally, here's a glam shot of the FCT with an M617 installed. Thanks for joining me on today's project! Special thanks again to @neale and @ckape for the hardware donation, which saved this shoestring project close to $200.
Major thanks to Vince Slyngstad for producing Warren's design, making it RPi-compatible, and making a 3D-printed base -- not to mention selling me this kit pre-assembled -- this is a pretty sweet package and will go a long way towards helping us keep the our PDP-12 up and running for years to come.
If you're interested in learning more about our PDP-12, or donating to the fund supporting this project, please see https://umdpdp12.blogspot.com/ or check out our videos on YouTube: https://www.youtube.com/playlist?list=PLHnc49MScQBBIlVIirpZ1Zjdh91U5Q6-6
#umdpdp12 #RetroComputing #VintageComputing #DEC #pdp #pdp12 #FlipChip
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Finally, here's a glam shot of the FCT with an M617 installed. Thanks for joining me on today's project! Special thanks again to @neale and @ckape for the hardware donation, which saved this shoestring project close to $200.
Major thanks to Vince Slyngstad for producing Warren's design, making it RPi-compatible, and making a 3D-printed base -- not to mention selling me this kit pre-assembled -- this is a pretty sweet package and will go a long way towards helping us keep the our PDP-12 up and running for years to come.
If you're interested in learning more about our PDP-12, or donating to the fund supporting this project, please see https://umdpdp12.blogspot.com/ or check out our videos on YouTube: https://www.youtube.com/playlist?list=PLHnc49MScQBBIlVIirpZ1Zjdh91U5Q6-6
#umdpdp12 #RetroComputing #VintageComputing #DEC #pdp #pdp12 #FlipChip
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Here's a video of the tester running a "fail stop" test -- testing the chip over and over again, stopping only on a failure.
#umdpdp12 #RetroComputing #VintageComputing #DEC #pdp #pdp12 #FlipChip
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Here's a video of the tester running a "fail stop" test -- testing the chip over and over again, stopping only on a failure.
#umdpdp12 #RetroComputing #VintageComputing #DEC #pdp #pdp12 #FlipChip
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It works! Here's a picture of the fully assembled unit, with an M617 in and powered, and a successful test on the screen behind it.
#umdpdp12 #RetroComputing #VintageComputing #DEC #pdp #pdp12 #FlipChip
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It works! Here's a picture of the fully assembled unit, with an M617 in and powered, and a successful test on the screen behind it.
#umdpdp12 #RetroComputing #VintageComputing #DEC #pdp #pdp12 #FlipChip