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  1. Twylo

    PDP-11/70 Microcode PROM images? (M8123 RAC)

    I've been toying with the idea of writing a microcode-level emulator. I think this can already be done with the KB11-A based PDPs, but not yet with the KB-11C based PDPs.
  2. Twylo

    PDP-11/70 Microcode PROM images? (M8123 RAC)

    Hi all, I'd like to see if anyone has ever dumped the PROMs on the PDP-11/70's M8123 RAC card. I've started the laborious process of transcribing the microcode firmware as listed in the M8123 engineering drawings (drawing number D-CS-M8123-0-1), but this is obviously tedious and error prone...
  3. Twylo

    AT&T UNIX PC enthusiasts out there?

    Hi! I love the UNIX PC as a concept, but oh my word I hate servicing them in any way! What a pain to open them up. I used to have three of them, including the coveted Ethernet adapters, but I gave them away to a friend a couple of years ago. He's put them to much better use than I ever did.
  4. Twylo

    Remaking Knight and SAIL keyboards

    Hi Lars, I'd be extremely interested, I'm surprised more people haven't jumped into this thread. It strikes me as the kind of thing that would sell well, perhaps up to a hundred units? I don't have anything to back that wild guess up, though. -Twylo
  5. Twylo

    AT&T DMD 5620 Terminal Emulator

    Hi all, I recently completed writing a DMD 5620 Terminal Emulator. This was the commercial version of the "Blit" or "jerq" terminal developed at AT&T Bell Labs for use with UNIX systems. I hope it's not too off-topic for this forum! Of course, to really get the best functionality out of it...
  6. Twylo

    LTL Freight shipping

    Hi all, I have just been given my dream setup - a number of AT&T 3B2/600G systems, peripherals, spares, and manuals. Over all, I'm going to guess this is one to two shipping pallets worth of stuff. The only problem is that it's all in Virginia, and I'm near Seattle, WA. I know I'm going to need...
  7. Twylo

    Looking for a VT52 DECscope keycap

    This weekend I picked up a VT52 DECscope terminal from a fellow collector. It's in fantastic shape, apart from being a little dirty and missing the number "6" keycap from the number pad. This is a real long shot, but if you have a permanently broken VT52 terminal you're keeping for parts, could...
  8. Twylo

    Coin Miner malware on the forum

    I just noticed my fans going crazy while reading the forum, and then Symantec popped up this warning: I'm not sure how it got here, but just a warning: Someone is mining cryptocurrency by inserting some random JavaScript into the forum, somewhere. -Twylo
  9. Twylo

    AT&T 3B2 Emulator is ready for users!

    Hi folks, I just wanted to post a quick note here that the SIMH AT&T 3B2 Emulator I've been working on for ages is finally ready for real users now. There are still a few things broken, but for the most part it seems to work pretty well. I've put up some documentation about how to get...
  10. Twylo

    DECstation 5000/133 Power Supply Repair (H7826)

    Hi all, Yesterday I picked up a couple of free DECstation 5000/133s. Upon inspection when I got them home on my bench, one power supply was dead, the other seemed OK, but failed almost immediately. The failure mode was completely non-spectacular. No blown caps, no blown fuses, the fans just...
  11. Twylo

    The State of the AT&T 3B2 Simulator

    Yes, I'm still working on it! Thanks to the gift of an anonymous donor, I have access to the 3B2 Off-Line Diagnostics manual, and that has helped me fix numerous bugs. The "Off-Line Diagnostics" referred to in the manual are the Debug Monitor (DGMON) tests available on the "3B2 Maintenance...
  12. Twylo

    Still seeking AT&T 3B2 documentation and help

    I have made tremendous progress! It turns out that yes, caching is REQUIRED. Without it, the OS changes pages under the MMU and expects the MMU cache to keep old segment and page descriptors. So, I fudged caching a bit by using the full SSL and PSL as tags. It seems to work. My stack...
  13. Twylo

    Still seeking AT&T 3B2 documentation and help

    It's been about a year since I last asked around, so it's that time again! Time for me to beg, on bended knee, for any and all documentation that might exist about the AT&T 3B2 architecture and internals. My 3B2 emulator sits unfinished, and likely will remain unfinished until I have access to...
  14. Twylo

    AT&T 3B2 Emulator - Still working on it!

    Still more progress, but it feels like one step forward, two steps back. Floppy commands are timing out, and I'm not entirely sure why. Sure wish I had better documentation!
  15. Twylo

    AT&T 3B2 Emulator - Still working on it!

    Just a quick note to say that I'm getting really, really close to booting UNIX in the emulator. I've implemented just enough of the MMU to support virtual space for the kernel. It's dying during boot because the free page table is corrupted somehow, but I'm working actively on it. We're getting...
  16. Twylo

    AT&T 3B2 Emulator - Still working on it!

    Hi folks, Just a general update, I'm still working on my AT&T 3B2 emulator based on the SIMH platform. It lay dormant for almost a year while I was dealing with life matters, but I've recently dived back in with a vengeance. I'm still desperately seeking any documentation or schematics that...
  17. Twylo

    WANTED: Symbolics Lisp Machine (yes, really!)

    Hi folks, This is as always a tremendous long shot, but I figured I would put it out there anyway...
  18. Twylo

    TDL-11 QBUS card?

    This TD Systems TDL-11 card came with the DEC stuff that I picked up last weekend. I can't find a single reference to the TDL-11 on the Internet, but there are references to the TDL-12, which apparently was much more common. The TDL-12 pretended to be an RLV-12 controller and mapped virtual...
  19. Twylo

    Looking for RX-50 diskettes

    Last week, I scored a big pile of free DEC gear, including a couple of MicroPDP-11's and about 6 RD52 drives, woo-hoo! Bad news: all the RD52 disks but two had been wiped clean some time in the early 2000s. They all have nearly empty RT11SJ installs with little more than DIR.SAV on them. Worse...
  20. Twylo

    Update on 3B2 emulator

    Hey all, I just wanted to share an update on the current status of my 3B2 emulator. I've been making a lot of good progress. I have enough of a WE32100 CPU core built to run the 3B2 firmware. It passes power-on self tests, and can run the built in firmware mode programs (like "version" and...
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