Computing from 1976

Paul Koning paulkoning at
Mon Jan 1 19:06:04 CST 2018

> On Jan 1, 2018, at 3:57 PM, David Bridgham via cctalk <cctalk at> wrote:
> On 01/01/2018 03:33 PM, Noel Chiappa via cctalk wrote:
>>> From: Paul Koning
>>> The only asynchronous computer I can think of is the Dutch ARRA 1
>> Isn't the KA10 basically asynchronous? (I know, it has a clock, but I'm
>> not sure how much it is used for.)
> This was my understanding, as well.
> More recently there was the AMULET processors designed at the University
> of Manchester.
> One of the stories I read about the AMULET was that they wrote a little
> program to blink an LED where the timing was determined by a busy loop. 
> If they sat a hot cup of coffee on the processor, the light would blink
> slower; a cup of ice water and it would blink faster. 

Neat.  I found this 2011 paper that's interesting:

The company I was trying to remember is Fulcrum, which was bought by Intel; they had morphed into an Ethernet switch chip company by then.  A pretty good one, as I recall.  But the original concept was a microprocessor, possibly a MIPS one, I don't remember.  The idea was that the chip speed would depend on how fast things happened to work, so different chips would run at different speeds due to process variations, and power supply and temperature changes would also affect things just as you described.

The paper I just mentioned lists a number of early computer designs as asynchronous, though it doesn't mention the ARRA 1, probably because it's not well known (a problem common to Dutch computers).  Also, those other computers did work.


More information about the cctalk mailing list