[TUHS] porting to different systems, Bootstrapping UNIX - how was it done

[Arnold Robbins via TUHS]

If I recall correctly, the labs port was to an Interdata 8/32.

John Levine via TUHS <tuhs at tuhs.org> wrote:

> According to Noel Chiappa via TUHS <jnc at mercury.lcs.mit.edu>:
> >2 - Move a set of existing software from one type of machine to another. (A
> >much more common event, now that we have portable software. Speaking of
> >portable software, I'm still amazed that this, which became one of Unix's
> >most important attributes, and a major driver in its spread, after V7, does
> >not appear to have been really thought about before V6/V7 was ported to
> >several other architectures.)
>
> I don't think it occurred to anyone until that that it would even make sense to
> move an operating system from one kind of computer to another. Historically,
> architectures were different, data formats were different, I/O architecture was
> different, and everything was written in assembler or maybe a language tied to
> the system like Burroughs Algol.
>
> By a decade after S/360 came out, computer architectures had all converged on
> 8-bit byte addressable two's complement designs with multiple registers. (Older
> machines like the PDP-10 weren't dead yet but it was just a matter of time.)
> Then Unix came along, written mostly in C which was highly portable to those
> 8-bit byte addressable machines. The group at the Labsy allegedly picked the
> Perkin Elmer 7/32 because it was as different as possible from the PDP-11, but
> it wasn't all that different. It was 32 bits but the data formats were the same
> (give or take a few details of floating point), addressing and memory protection
> were similar to the PDP-11, and it had terminals and disks.
>
> Wollongong and the Labs separately did 7/32 ports, both probably observing
> that if they retargeted the C compiler to the 7/32 and recompiled the PDP-11 
> C code, they were about 80% of the way there, so the rest of the work was
> a manageable project.
>
> R's,
> John
> -- 
> Regards,
> John Levine, johnl at taugh.com, Primary Perpetrator of "The Internet for Dummies",
> Please consider the environment before reading this e-mail. https://jl.ly