[TUHS] A New History of Modern Computing - my thoughts

Adam Thornton athornton at gmail.com
Mon Nov 29 09:35:01 AEST 2021

Getting a bit far afield from Unixes, but A Quick Rundown Of Instruction
Sets I Have Known, more or less in the order I learned them:

6502: you never forget your first love, and, sure, it's constrained, but
it's elegant and concise and I still adore it.
68k: Lovely.  I used it before I ever used the PDP-11, but in retrospect
it's like the PDP-11 but more so.  Roomy, comfortable, regular.  Too bad it
lost to x86 in the marketplace.
8051: I mean, OK, I get it, you need a low-cost embedded architecture and
it's the 1980s, but...yuck.
x86-and-descendents: the less said the better.  Maybe I just don't like
Intel's designs?
SPARC: It's not bad.  Having lots of registers is nice.  But by the time it
came along compilers were good enough that I never actually needed to use
it in anger.
S/360-and-descendents: The S/360 is OK, even nice, in a very 1960s IBM
way.  And then its evolution just KEPT adding ever more baroque filigrees
onto it.  Don't get me wrong, I love SIE, because I love VM, but even that
is kind of a bag on the side, and by the time you get to System z...this is
what happens when you don't start over from a clean sheet every so often.
PDP-11: There's a very good reason it was used as a model architecture in
coursework for decades.  Also regular and comfortable.
TI-99/4A (more or less TI 9900): I like microcode as much as anyone but
honestly this is pretty silly here, folks.

These days I'm kinda sorta poking at RISC-V and ARM.  Not that I need to,
but they seem nifty.


On Sun, Nov 28, 2021 at 4:15 PM Noel Chiappa <jnc at mercury.lcs.mit.edu>

>     > The ++ operator appears to have been.
> One would expect that most people on this list would have read "The
> Development of the C Language", by Dennis Ritchie, which makes perfectly
> clear
> (at 'More History') that the PDP-11 had nothing to do with it:
>   Thompson went a step further by inventing the ++ and -- operators, which
>   increment or decrement; their prefix or postfix position determines
> whether
>   the alteration occurs before or after noting the value of the operand.
> They
>   were not in the earliest versions of B, but appeared along the way.
> People
>   often guess that they were created to use the auto-increment and
>   auto-decrement address modes provided by the DEC PDP-11 on which C and
> Unix
>   first became popular. This is historically impossible, since there was no
>   PDP-11 when B was developed.
>     https://www.bell-labs.com/usr/dmr/www/chist.html
> thereby alleviating the need for Ken to chime in (although they do allow a
> very efficient implementation of it).
> Too much to hope for, I guess.
>      Noel
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