And how would you expect a POE program (or any other program in this respect) to know how much time your computer 'loses' ?

I wouldn't want it to know about lost time. That's not the concern.

As far as I can see it, it is possible for software to make the system clock loose time. When the PC boots the OS reads the time from the CMOS clock. But from now on, as I see it (tell me if I'm wrong) the CMOS clock is not polled but time is instead kept in the OS and updated using some kind of interrupt scheme. So, this is a (partly ISR) routine that's called regularly.

Now, a software can somehow prevent the servicable periodicity of that clock-updating routine by very small amounts, and it could accumulate over time, resulting in a system clock that's a bit behind. Of course, next time the PC is rebooted, the time is read from the CMOS clock and everything's fine again. That is, if the CMOS clock was not automatically updated from the system clock at shutdown.

A spreadsheet software won't do that kind of interference. A game could (look at some Windows games). Or a software that schedules tasks close to the hardware interface.

Hence, my question about POE on a mostly embedded platform (i.e. no NTP access): has experienced POE developers seen any degradation in system-keeping time when POE was active 24/24 over long periods of time ?

In reply to Re^4: POE and time by carcassonne
in thread POE and time by carcassonne

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