First computer with real-time clock?

From: Tom Jennings <>
Date: Mon Aug 2 14:33:48 2004

On Sun, 2004-08-01 at 15:32, Vintage Computer Festival wrote:

re: computer 'subsystem' to produce clock time

> Hmm, okay. Then I guess what we'd be looking for is some device that
> keeps continuous time. ... It would just have to be a
> combination of hardware and software that kept the current date in the IBM
> 650.

Are you looking exclusively at the IBM 650, or any computer? Does it
have to be an 'automatic, electronic, digital, stored-program,
computer'? Time-stamping of 'data' trivially dates to telegraph/teletype
equipment -- I've seen stuff from the 1930's that does it.

I know you don't want tty stuff but just to point out that the goal
still seems vague to me.

> > My favorite on the opposite end, is a random bit stream produced by
> > using the pulses from a geiger counter (and associated radioactive
> > material) to clock a long shift register. It's well-discussed, but I'm
> > not sure anyone ever produced one.
> How fun. You'd have to shield it pretty heavily though or else your PC
> would be glowing at night (talk about a case mod!)

(Nahh, it could be a very small source, like a smoke detector. Not very
dramatic though as a big scary lead coffin though :-)

> Has anyone ever produced a random number generator that pulls it's "seed"
> from the random background radiation you get on a TV set on a dead channel
> (snow)?

Oh I'm sure from the principal, yes, thermal noise would be a great
source. Zener noise is easy too, not sure of it's distribution.
Received on Mon Aug 02 2004 - 14:33:48 BST

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