There is this:
http://www.philpem.me.uk/code/3b1emu/
It does boot UNIX, although there is further issues which prevent things like cc from running. But if you want to poke around as a user, it’s enough to do that.
Sent from Mail for Windows 10
From: Ed Carp
Sent: Friday, 8 December 2017 4:49 PM
To: Cory Smelosky
Cc: tuhs@tuhs.org
Subject: Re: [TUHS] AT&T 3B2/400 Emulator
Speaking of which, does anyone have any plans on writing an emulator
for the 3B1 (aka PC7300)?
On 12/7/17, Cory Smelosky <b4@gewt.net> wrote:
> Heh incidentally I am awaiting the arrival of a 3B2/400 and already have a
> Definity...;)
>
> Sent from my iPhone
>
>> On Dec 7, 2017, at 18:36, Jason Stevens <jsteve@superglobalmegacorp.com>
>> wrote:
>>
>> Wow so glad you got it to boot!
>>
>> It’s great that this reference platform is now ‘alive’ through emulation.
>> To say these machines are super hard to find these days is difficult is an
>> understatement. Even in the mid ‘90s finding anything for these beasts
>> was a monster chore.
>>
>> Outside of college and using them for style and diction, I’ve only seen
>> one paired with an AT&T Definity phone switch, but everything was quickly
>> moving to NCR/SUN.
>>
>> Great job!!
>>
>> Sent from Mail for Windows 10
>>
>> From: Seth Morabito
>> Sent: Thursday, 7 December 2017 3:10 AM
>> To: tuhs@tuhs.org
>> Subject: [TUHS] AT&T 3B2/400 Emulator
>>
>>
>> Hello everyone,
>>
>> A few weeks ago, I merged my work-in-progress AT&T 3B2/400 emulator
>> into the main SIMH source tree, and I realized that I should mention
>> it here, where there may be particular interest.
>>
>> The 3B2 and 3B5 were main porting platforms for AT&T System V Release
>> 3, and when I realized how scarce the equipment has become to find, I
>> set out to write an emulator for the 3B2. It was rough going at points
>> due to lack of documentation, but I was able to reverse engineer quite
>> a bit of the system through reading the SVR3 source code, and of
>> course strapping my own 3B2/310 to a logic analyzer.
>>
>> The emulator is fairly complete. It certainly works well as a
>> standalone, single-user UNIX system. Support for multiple terminals is
>> coming very soon (as soon as I find the time, that is) so it will soon
>> be possible to allow multiple users to telnet into virtual terminals,
>> similar to how the SIMH PDP-11 and VAX emulators work.
>>
>> For now, information about the emulator lives here:
>>
>> https://loomcom.com/3b2/emulator/
>>
>>
>> Best Wishes,
>>
>> -Seth
>> --
>> Seth Morabito
>> web@loomcom.com
>>
>