First computer with real-time clock?

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Thu Jul 29 18:40:40 2004

>
> On Wed, 28 Jul 2004, Wayne Smith wrote:
>
> > HP-75C had one built in.
>
> Hmm. Interesting. That's early 1980s, if not late 1970s, correct?

Early 1980s 1982 I think, but the Museum of HP calcultors would tell you
for sure.

The HP41CX does too (and the timer module for the older HP41s includes
the same clock chip, codenamed Phineas IIRC).

I think the HP75 clock (like the clock in the HP71, and the one for the 41
series) is just an up-counter that counts pulses from a crystal and relies
on software to turn it into time/date.

Of course the Sharp PC1500 and Tandy M100 also have built-in
real-time clocks (actual hardware chips that are read out in software).

I remember clock cards for the Apple ][ (in fact I know I have one
somwhere, it's got a NiCd PP3 battery stuck to it...)

-tony
Received on Thu Jul 29 2004 - 18:40:40 BST