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

Dan Halbert halbert at halwitz.org
Mon Nov 29 23:48:54 AEST 2021

On 11/28/21 6:35 PM, Adam Thornton wrote:
> 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.

When I was in high school, I loved reading about instruction sets. I 
recommend the first five volumes of Annual Review in Automatic 
Programming, if you are interested.

The DEC instructions sets were all quite elegant, from the minimal PDP-8 
(nee PDP-5) 12-bit machine to the PDP-10 (nee 6). I maintained the BCPL 
compiler at BBN for a while in the 1970's, and it was a pleasure to 
figure out what machine code to generate.

Then there was RISC vs CISC, where the VAX was a major punching bag. I 
was at Berkeley for RISC-I, and was a part of the small student group 
that did its register windows scheme.

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