First computer with real-time clock?

On Sun, 1 Aug 2004, Tom Jennings wrote: Hmm, okay. Then I guess what we'd be looking for is some device that keeps continuous time. I.E. you set it once, and through some manner of both hardware and software, produces the correct current date and time upon request. As far as need to keep the time during power off, I don't know that in this case it would matter too much. It would just have to be a combination of hardware and software that kept the current date in the IBM 650. The 650 was small enough that you could power it down during off hours, though I don't know what actual practice was (perhaps it was too much of a chore to boot up so it was kept on all the time). At any rate, as long as the 650 had some way to generate uniform time pulses, a real-time clock/calendar could be implemented, but this would probably have to be at a hardware level since the 650 was primarily a batch machine, or it would have to be programmed to store the date/time in some memory location that the other applications would not touch, and then some counter would have to be implemented that could update a memory location with the number of ticks since the last access or whatever. Of course, as I've been suggesting, there could have been a totally separate clock/calendar device (heck it could have even been mechanical) that kept the local time/date and then transferred it to the 650 upon request. Just like the clock in a modern PC. 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!) Has anyone ever produced a random number generator that pulls it's "seed" (snow)? -- Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org [ Old computing resources for business || Buy/Sell/Trade Vintage Computers ] [ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]