First computer with real-time clock?

From: Vintage Computer Festival <>
Date: Mon Aug 2 04:45:07 2004

On Mon, 2 Aug 2004, Hans B PUFAL wrote:

> OK, I've sent this question to the IBM Haus of History in Sindelfingen
> in Germany. They have a working 650 so should be able to provide an
> answer. I'll keep you informed.

I didn't think of doing that! Thanks!!

> The periodic interrupt (50 or 60 times a second depending on which side
> of the pond you were) was most definitely available in 1964 on the IBM
> System/360. At each tick, the hardware decremented a word in memory and
> when it overflowed to zero, a program interrupt was invoked. The handler
> would do whatever it needed and reset the memory word.
> Earlier IBM machines also some form of this feature. On the 7094
> modified for CTSS it was an IBM special feature.

Yes, from what I've been told, the 7090/7094 had a clock feature of some

Sellam Ismail                                        Vintage Computer Festival
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Received on Mon Aug 02 2004 - 04:45:07 BST

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