First computer with real-time clock?

Vintage> The overall discussion is very useful, but in my particular Vintage> case, it needs to pertain specifically to the IBM 650, Vintage> because the assertion at hand is that a document used to Vintage> discredit a certain scientist's claim to a certain Vintage> achievement has a date stamp on it that is claimed was Vintage> produce by the IBM 650 using its internal clock feature. Vintage> The 650 does not have such a feature inherently, so now I'm Vintage> trying to determine if there was ever an adjunct product Vintage> that IBM produced to give the 650 the ability to tell time. It sure doesn't look like that from the docs on Al Kossow's website. It seems that the 650 doesn't have interrupts, which would make a simple periodic tick type system pretty problematic.

If the exercise is to attach the credibility of the document, it looks to me like you have enough data to do that. You can clearly say "there isn't any such thing as an 'internal clock feature' on the 650". That puts the ball in the other party's court, to try to demonstrate that there did exist some obscure add-on of which not a word appears in the dozen or so IBM docs that are on-line.

And even then, another question becomes whether the time stamp is real or a forgery, independent of what machine generated it.