First computer with real-time clock?

From: Paul Koning <pkoning_at_equallogic.com>
Date: Thu Jul 29 09:11:49 2004

>>>>> "Vintage" == Vintage Computer Festival <vcf_at_siconic.com> writes:

 Vintage> On Wed, 28 Jul 2004, Marvin Johnston wrote:
>> Assuming that you are not talking about S-100 clock/calendar
>> cards, the Lobo Drives Max-80 had a built in clock.

 Vintage> I'm thinking farther back. Was there any mini or mainframe
 Vintage> that had a real-time clock built in or as an add-on option?

 Vintage> It's come up in some litigation. The actual issue at hand
 Vintage> is that someone was able to overturn a patent by claiming
 Vintage> the IBM 650 had a real-time clock built in. They "proved"
 Vintage> this by submitting as evidence a printout that had the date
 Vintage> printed on it(!) I've checked the IBM 650 Manual of
 Vintage> Operation and it makes no mention whatsoever of a real-time
 Vintage> clock. I pretty much figured it wouldn't but I of course
 Vintage> had to do due diligence.

 Vintage> But it made me wonder: what was the first computer to have a
 Vintage> built-in real-time clock?

I second the question -- defined how?

For answering the litigation, you'd really need to know that...

If the answer is: a device that maintains the time of day independent
of the computer power, the oldest I know of is the DEC KW11-W (?not
sure about the suffix). I don't remember when that came out, but it
probably predates microcomputers. It wasn't a popular option.

Another example, from roughly the same era, is the TOY clock in the
Pro-350. That's a microcomputer chip, so presumably some PC type
system offered it as well. (That may apply to the KW11-W as well... I
don't know.)

On the other hand, if the definition is a device that allows the
computer to keep time while it is powered on -- which is all that you
can deduce from the 650 example you quoted -- then certainly it goes
as far back as the CDC 6600 (1964) and probably a lot further. Then
again, that's after the IBM 650.

By either definition we're talking about something that came out well
over 20 years ago, so it would be "prior art" invalidating any current
patent.

        paul
Received on Thu Jul 29 2004 - 09:11:49 BST