[Simh] AT&T 3B2 Emulator

[Seth Morabito]

Hi folks,

After several years in the making and lots and lots of reverse
engineering, I'm happy to announce that the AT&T 3B2/400 emulator now
boots and runs multi-user SVR3 UNIX.

For the time being I have forked SIMH to my own GitHub account. If and
when the SIMH maintainers feel that the time is right, I'll be happy
to merge the 3B2 simulator into the main SIMH repo.

Right now I would consider this alpha-quality software. It runs, but
there are many missing features. The short form TODO list includes:

  - Pass ALL off-line diagnostics (DGMON)
  - Enable IDLE support
  - Add support for the CONTTY serial port
  - Add EPORTS card support for more serial lines
  - Lots and lots of code cleanup; some of it is very kludgy

For more information, please see:

    https://loomcom.com/3b2/emulator/

Corrections, comments, and feeback are welcome!

-Seth