[TUHS] mental architecture models, Anyone ever heard of teaching a case study of Initial Unix?

[John R Levine]

On Sat, 6 Jul 2024, Clem Cole wrote:
> ESPOL predators all of them, although one can say since it was only
> available on Burroughs large, medium, and small systems - it was retargeted,
> but not widely used.

Good point.

> Other systems programming languages followed, BCPL, BLISS, PL/360 and even
> B before C. If you consider PL/M a child of PL/360 (which is was more than
> child of PL/1 if you look at it), all of the others have code generators
> and libraries for multiple ISA and OS and did before C did. That said, I
> don't think any fo them have as many targets as C and many FORTRAN.

Untangling the sequence of all this stuff is hard.  BCPL was indeed 
retargeted at a lot of machines but it's not clear how portable programs 
were since the word sizes varied so much from 16 to 60 bits, but couldn't 
deal with byte addressed memory which is a large reason we have C.

The original version of BLISS was only for the PDP-10.  DEC retargeted it 
to the PDP-11 and VAX, but I think that was after Unix moved to the 
Interdata and possibly other machines.

PL360 was Wirth's implentation language for Algol W, a 360 assembler with 
Algol-like syntax that had nothing to do with PL/I and only targeted the 
360.  I used it, it was pretty nice.

Are you maybe thinking of IBM's PL.8 or PL/S?  The former was originally 
for the 801, later S/360 and ROMP, the latter used for S/360 system 
programming.  PL.8 was about 80% of PL.I, hence the name, PL/S a subset 
with some hackery like register declarations and in-line assembler.

R's,
John