7 Nov
2005
7 Nov
'05
7:06 p.m.
They never did make a big dent in the punched card
world, did they?
And to add to that, later S/3s could be fitted with 80 column card
devices!
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.
I think the bizzare instruction set of the S/3 stems from the the need for
the machine to deal with characters - RPG and such - almost
exclusively. FORTRAN was offered but it must have really sucked.
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