[TUHS] B Source Code

[Clem Cole]

CMU/CS implemented CSAV and CRET on the 11/40e (6th edition++).  IMO - it
was a mixed bag.  I've forgotten the statistics, it was a few ticks fasters
for saving the registers, which was good.   The primary thing it did was
save a small amount of address space on the non-I/D 40  - which was helpful
for applications as they got larger and were running out of address
space...... But it was PITA in practice because it meant that binaries
compiled on IUS and SUS (the UNIX two systems in CS), would not run
anywhere else on campus which were mostly 11/34 or later 11/34A's and it a
networked environment (which we were just starting to create) the seams
tended to show a little more than we would have liked.

IIRC I eventually got a emulator working at Mellon Institute and EE systems
so they binaries would not core dump, but we just recompiled we ran into
them.

The real solution to address space issue was when DEC released the 11/44
which was separate I/D (11/70 class) and the thunk work that we did in
2.9BSD in trying to move 4.1/4.2 code to the 11.

FYI:  Danny Klein and I should have the compiler somewhere (and the
microcode) is I ever get my CMU archives off tape.  It's on my list of
things to look for.

Clem



On Thu, Sep 14, 2017 at 11:59 PM, Dave Horsfall <dave at horsfall.org> wrote:

> On Thu, 14 Sep 2017, Noel Chiappa wrote:
>
> Interesting factoid: The PDP-11 initially used a threaded FORTRAN
>> implementation. In line with the observation above (about a new virtual
>> machine), DEC actually looked into writing microcode for the -11/60 (which
>> had a writeable control store) to implement the FORTRAN virtual machine.
>>
>
> Did anyone actually use the WCS?  I had visions of implementing CSAV and
> CRET on our -60, but never did get around to it.  Too late now...
>
> --
> Dave Horsfall DTM (VK2KFU)  "Those who don't understand security will
> suffer."
>
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