bit slice chips (was Re: Harris H800 Computer)

Chuck Guzis cclist at
Sat Apr 23 12:06:05 CDT 2016

On 04/23/2016 05:41 AM, Noel Chiappa wrote:
>> From: Brent Hilpert
>> I'd say the 74181 (1970) deserves a mention here. Simpler (no
>> register component, ALU only) but it pretty much kicked off the
>> start of IC-level bit slicing.

I recall reading about the 74181 introduction back in the day--it
created great excitement and speculation about how far the industry was
from a computer-on-a-chip.  I think I still have a couple of the things
in my hellbox.

In the day, I'm not certain that TTL had the edge on integration,
however.  It always seemed that DTL and RTL had the edge in complexity.
 Before the 181, I was playing around with the RTL 796 dual full adder
and an 8-bit Fairchild DTL memory--IIRC the latter used a 7V clock.

The interesting thing was that there seemed to be a distrust of LSI
chips early on.  I recall working on a project around 1973, where the
lead engineer preferred to design his own UART from SSI rather than use
one of the new UART chips.


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