bit slice chips (was Re: Harris H800 Computer)

Brent Hilpert hilpert at
Sat Apr 23 20:05:57 CDT 2016

On 2016-Apr-23, at 4:15 PM, Jon Elson wrote:

> On 04/23/2016 05:46 PM, Chuck Guzis wrote:
>> On 04/23/2016 02:34 PM, Brent Hilpert wrote:
>>> I was surprised by the early date code on the 7490s when I ran across
>>> them in a piece of test equipment.
>> What was surprising to me is how quickly the industry standardized on
>> the TI 7400/5400 parts.   Early (ca 1967) Moto databooks had MTTL I,
>> MTTL II and MTTL III that were essentially sui generis.  By 1969, the
>> MC7400/5400 had pretty much taken over.  Things moved really quickly
>> back then.
> Lots of designers and system manufacturers were VERY leery of adopting anything single-source.
> When a number of chip makers (Nat Semi, Motorola, Signetics, Fairchild) all jumped onto making compatible 7400 parts, the industry had the confidence that parts in the series would be available for a long time.  Back in the late 60's, early 70's the industry was moving at a breakneck pace, and chip families had very short lifetimes before their makers hopped onto the next new thing. (Oh, yeah, you said the same thing in the last sentence!)

Fellow here did some research into the 181 history and came to a similar conclusion:
He suggests TI being the first to contract for a second-source sent the buyers (esp. military) to the 7400 series.

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