> -----Original Message-----
> From: piclist-bounces@mit.edu 
> [mailto:piclist-bounces@mit.edu] On Behalf Of Lembit Soobik
> Sent: Wednesday, February 15, 2006 7:06 AM
> To: Microcontroller discussion list - Public.
> Subject: Re: [OT] Computer built using relays (with link this time)
... 
> We developed the new generation machines using core memory 
> and blocking 
> oscillators (rather than flip-flops, monoflops) because they 
> worked with 
> only one transistor. Transistors were expensive, around 5 to 
> 10 $ a piece.
> 
> Lembit

My first job in the Air Force was working on teletype crypto machines
that used magnetic logic; the analog of a flip-flop was called a
ping-pong.  That was two cores passing a '1' state back and forth, idle
was a '0'.  I always wondered if anything other than those crypto
systems ever used that type of logic.

GC

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