View Full Version : Looking for AT&T 3B2 ROMs and info

December 16th, 2014, 01:02 PM
Hey folks,

I've started down the path of implementing an AT&T 3B2 simulator using the SIMH platform. Key to doing this will be access to 3B2 ROMs and technical information, both of which have proven very difficult to get ahold of.

Right now I'm working from the 3B2 information publicly available on Bitsavers and Unixwiz.net, plus I have remote Telnet access to a 3B2/600 so I can use the compiler, assembler and disassembler tools on a running platform. I've also been reading through the AT&T SYSVR3 source code purloined from anonymous sources, and the GPL'ed AT&T 5620 cross-development tools (it's not a 3B2, but it does use the same WE32100 CPU).

If anyone has AT&T technical documents that might be useful, or can provide dumps of 3B2 ROMs, please do let me know! I'm open to just about any model of 3B2 right now, whatever I can get my hands on.


December 16th, 2014, 02:37 PM
I have a 3B2-400 but I was hoping someone else would swoop in and beat me to it lol

I'll try and find some time over the weekend to dig it out and get the EPROMs read. I'll need to remove them as the machine currently isn't booting UNIX. The ROMs are good, but I need to sort out the hard drive situation - perhaps this will get me motivated enough to get the machine running properly.

I have ~8 books to go with it, but from memory they were all available online in PDF format already.

December 30th, 2014, 12:23 PM
I'll try and find some time over the weekend to dig it out and get the EPROMs read.

Hi SpidersWeb!

Sorry I haven't replied before now, but that would be fantastic. I've managed to track down the ROMs for a model 310, but I would love to know how (or if) they differ from the model 400.

Let me know if you can read those ROMs, I'd love to see them.


December 30th, 2014, 12:24 PM
Just a brief follow-up to my own thread:

I've been pretty actively continuing my hunt for this info, and I've started to keep a log of everything that I've learned.

The info is available here on my website: AT&T 3B2 Internals (http://www.retronet.net/~seth/3b2.html)

I'll keep updating the page as I learn more!


January 6th, 2015, 08:58 PM
I'd like to +1 this request as I just received a 3B2/300 which has three of the four EPROMs missing entirely, and need to be able to program replacements to get the thing working again. If you have a 3B2/300 but don't have a way to dump the EPROMs, PM me and we'll see if something can't be worked out.

edit: apparently there were 32100-based and 32000-based /300 systems. I have a 32000-based system (one big multi-chip module soldered to the mainboard, not multiple chips in sockets), as this probably matters. The EPROMs are probably marked AATKJ, AATKK, AATKL, and AATKM. FWIW AATKL is the one that's still in place. AATKM should apparently also bear a "3" marking (for the /300).

January 12th, 2015, 12:47 AM
Apologies for being extremely slow - was distracted over the break and then when I finally pulled it out, I got sucked in to attempting to get it running again (it has a hard drive write fault - seems to be motherboard related)

Anywho they are AAYYC AAYYD AAYYE and AAYYF-4 and there was a 32100 CPU next door

Installation order, front of machine facing you, pin 1 of chips facing rear of machine:

http://i83.photobucket.com/albums/j307/DrRabid/IMG_0046_zps0ec259b0.jpg (http://s83.photobucket.com/user/DrRabid/media/IMG_0046_zps0ec259b0.jpg.html)

Zip file: http://www.baudband.net/downloads/3b2-400.zip

Unfortunately the EPROMs in my tape and serial cards are soldered in, so couldn't easily grab those.

I'll likely fix mine one day in the future (been through multiple pre-tested drives, cables etc, 90% confident the write signal is weak) but if anyone finds a spare 400 motherboard floating about I'd be keen to purchase.