The Timer/Clock interrupt is IRQ 0 no other interrupt has a higher priority, therefore this interrupt is rarely missed. If it were missed then interrupts would have to be turned off longer the 110ms (2 times the clock rate) which is an enormous amount of time and due no doubt to an improperly written device driver or faulty motherboard/card.
Having said this; a device driver writer would not have interrupts turned off for long anyway, this is a bit heavy handed on a system. That's what IRQL are for. 99.9% of ISR routines are microsecond range. So this is not a source of lost timer interrupts. Time is extremely important on a telescope (which why I'm going to try the TAPR Clock Block when I get time) and I've studied this issue of lost timer interrupts. I can tell you that they just don't occur even when the system is loaded to the max. We have a watchdog card in our system to detect just such an event, it has never triggered (except when you push the test button). Jack _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
