Recent content by Twylo

It "runs", but it really is such a skeletal system that it isn't doing anything useful yet! :) I like Elektraglide's idea of using Brad Parker's Sun-2 emulator as a starting point, it makes a lot of sense.

The ROM is mapped into RAM space by default at startup (0x000000 to 0x1fffff). This is turned off when the sound generator is initialized by writing to 0x788000. This is sort of documented in the service manual...

I have the start of a Tektronix 4404 emulator here if you're interested in looking it over / getting ideas / grabbing anything. Sadly, I didn't make it very far, it's really skeletal. I did not actually implement very much of the SCSI stuff yet, so that won't be helpful to you, but there may be...

Hi mindpixel, I'm sorry I didn't see this until just now! I haven't been checking the forums a lot lately. If you haven't already gotten the answer yet (I hope you have), the console wants 7S1 (7 bits, Space parity, 1 stop bit). You can actually get away with 8N1 for the built in firmware, but...

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.

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...

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.

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

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...

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...

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...

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

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...

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...

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...