The AT&T 3B2 was a line of UNIX desktops and servers produced jointly by Western Electric and AT&T starting in 1984, shortly after the Bell System breakup allowed them into the computer market. They are primarily of historical interest because the 3B2 was the main porting platform for AT&T UNIX System V Release 3.
I first became interested in the 3B2 series in 2014, just out of curiosity, and tried to find one. I couldn’t. It turns out they are vanishingly rare, and anybody who knew the architecture well is long retired. So, I set out to reverse engineer and document the 3B2 as well as I could, and to preserve some of the knowledge, history, and software for future generations to study.
In addition to the pages listed here, I maintain a structured 3B2 Software and Documentation archive.