🚀 go-pugleaf

I have written a profiler for JPI Modula-2 under DOS (*), based on the
scheme presented in DDJ Oct 92. However, rather than using the standard
trick of speeding up the 8253/4 timer interrupt, IRQ0 (because we had
other uses for that...), I decided to use the AT RTC Interrupt, IRQ8,
at the rate of 1024 times a second. I got it working perfectly, no real
problems, on several machines.

However, as soon as I try it on one particular machine, with a
particular motherboard... (in a terminal we have ordered 650 of....),
it doesn't go. The interrupt handler is set up, but no interrupts ever
arrive... It's as if the RTC hardware isn't there.... but it is!

My next step is to find some other program that uses that interrupt,
and see how that goes...

Anyway - does anyone have similar experiences with the RTC interrupt?
I believe I am delaying long enough between port accesses.
(The motherboard manual discusses a bit in the chipset which allows
the RTC interrupt to come from another source, but this appears to be
set correctly.

This interrupt doesn't seem to be used very much - is this why?