The Real Time Clock - Answers, not questions :)

The Real Time Clock - Answers, not questions :)

Post by Ralf Brow » Tue, 15 Feb 1994 05:49:17

}  8192 ints per second is an awful lot for slow computers.

For a well-written interrupt handler, an 8 MHz 8088 will suffice at that
rate, so any machine with an AT-style real-time clock should be able to
handle even 8192 interrupts per second.  I ran a print-spooling
interrupt handler at 2330 interrupts/sec using only 30% of a 4.77 MHz
8088 (the rate was that high to pump out the 1000 bytes/sec of graphics
needed to keep the printer running at full speed, with the printer
unable to accept data about 1/4 of the time).  That included checking to
see if the printer was ready for another byte, sending the byte and
updating the buffer pointers, updating the down-counter that controlled
whether to pass through to the old INT 08h, and issuing an EOI if not
passing the interrupt through.

Quote:}Ralf Brown's interrupt list is available from several ftp sites. Ask an archie
}server for "prog inter3". I think the actual version is 38.

It went up to 39 last weekend.


FIDO: Ralf Brown 1:129/26.1 | "Life is great--I wouldn't know what I'd do


1. Real Time Clock interrupt questions

I have a few questions about the Real Time Clock interrupt:

1) Is it 100% independent of INT8?  i.e. it does not call INT8 or INT8 does
   not call INT70h (the RTC interrupt)?  I am certain that it doesn't, but
   want to ask just to make sure.

2) Does changing the rate of the RTC interrupt affect the time in the RTC at
   all?  I am certain it doesn't.

Thanks for any info/help/code!

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