Variable Word length CPU

[A. G. Carrick]

The story I hear was that the System/3 was built by a CE in his home using
salvaged parts and adopted by IBM as a product. I have no references to
prove it. If so, then there was no logic to the decision. The 360 was just
way too big a design to strip down as the comments on the model 20 show. The
sys 3 was for really small offices.

IMHO the most bizarre thing was the twinax cabling. That line and some Wang
systems were the only ones I ever saw. Not being a hardware guy I have no
idea if there is any advantage for twinax over coax.

Gil 

...
> > While the S/3 instruction set bears certain similarities to 
> the S/360, 
> > I've wondered what IBM's logic was for making it so 
> different from the 
> > S/360.  I doubt that it was technical--the 360/20 was far more 
> > brain-dead than the
> > S/3 and customers still used them, in spite of the crippled 
> > instruction set.
> 
> The S/3 line was...special. 
...
> There are only 30 or so instructions in the whole set, yet a 
> number of them are for complex string handling (kind of 
> inpressive for a non-microcode machine to do string inserts, 
> actually). There are no simple byte level instructions - 
> everything that goes thru the ALUs are strings, basically. 
> Everything is a string. Thw world is a string to an S/3.
> 
> And yes, the S/3 is a real variable word length machine! Yes, 
> you can add two 569 byte integers with one instruction!
> 
> William Donzelli
> aw288 at osfn.org
>