[Simh] Older Model VAX simulators, what can you do with them and how do they work?

[Clem Cole]

On Mon, Oct 10, 2016 at 12:08 PM, Ray Jewhurst <raywjewhurst at gmail.com>
wrote:

> I just wanted to clarify that I am interested in all of the BSDs. I just
> started with 3BSD because I am already somewhat familiar with 29BSD and
> 211BSD. So I thought it would be a good transition.
>
Ah I think you fell into the Berkeley UNIX naming trap (see below).  As
even 4BSD is not going to be recognizable from 2.9/2.11 which was where the
4.2 exts were being added).
                  EE/CS hacking                                    CSRG
formed here

           |
Time line:  BSD (aka 1) -> 2 BSD  -> 3 BSD -> 4BSD -> 4.1BSD -> 4.1A/B/C ->
4.2
                                            |
               |                 |                 |
                                            +.............................
.........2.x..+.....2.8.......................2.9 .....

Basically, the PDP-11 development in EE/CS stopped for a couple of years
until Keith Bostic started to hack on it as an undergrad.   CS Dept had
switched over to VAXEN as the primary development was on those systems
because that was what DARPA was paying for by creating CSRG.   But there
were pockets (like Keith in Math or Stat Dept IIRC) that wanted the cool
stuff from the Vaxen and it was  amazing what started to appear in that
updated line.   I do not remember who donated the thunk support but that
was not original done at USB.   But folks outside of CRSG had been working
on ways to break the 16 bit address issues mostly to let the kernel get
bigger. The desire to pick up the BBN networking stack and then the "Pure
Joy" rewrite from the Vax was the big driver.     Actually before I would
join UCB as a grad student, I had written and donated the extended memory
stuff for the a number of processors (60, 44) as well as the ENABLE which
landed in there somewhere, (ENABLE allowed you have up to 4M of memory on
an 11/40 class system - there were a lot of 11/34's in the wild).
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