Interested in UNIVAC 9000 Series (and IBM 360)
elson at pico-systems.com
Fri Nov 18 17:15:54 CST 2016
On 11/18/2016 02:04 PM, Chuck Guzis wrote:
> Models? Wasn't the 9300 basically an
> instruction-compatible model of the S/360 Model 20? I
> think the 9400 was the bottom end 360/30 model compatible.
> Calling the Model 20 a "member of the System 360 line" has
> always been a bit of a stretch in my book.
OH, yeah! Besides the limited instruction set, short
registers only half populated, etc., did you know that the
360/20 did not have an adder? It could only
increment/decrement. The data paths were only 4 bits wide,
so to add a 3 in register A to a 5 in register B, it
decremented A and incremented B until A went negative. It
did this for each nibble. I'm guessing a 16-bit add took
over 100 us. I'd ALMOST reject calling this a COMPUTER!
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