[comp.unix.sysv386] Reliable Clock

briant@tsltor.uucp (Brian Taylor) (05/31/91)

We run several "pseudo" real time applications on our UNIX systems (ISC 2.2.1)
but notice that like all DOS systems, the clock on these systems leaves a LOT
to be desired (to say the very least).

Could anyone recommend a reliable clock (i.e., one that wouldn't lose more than
a few seconds yearly or better) that is supported under ISC?  Any ideas of whom
I can contact is also welcome.

AtDhVaAnNkCsE		...briant
-- 
Brian Taylor					briant@tsltor.uucp
UNIX Systems Administrator			(...jtsv16!tsltor!briant)
Teleride Sage Ltd.				(416) 596-1940

lance@motcsd.csd.mot.com (lance.norskog) (06/05/91)

briant@tsltor.uucp (Brian Taylor) writes:

>We run several "pseudo" real time applications on our UNIX systems (ISC 2.2.1)
>but notice that like all DOS systems, the clock on these systems leaves a LOT
>to be desired (to say the very least).

>Could anyone recommend a reliable clock (i.e., one that wouldn't lose more than
>a few seconds yearly or better) that is supported under ISC?  Any ideas of whom
>I can contact is also welcome.

By real-time do you mean minutes, seconds, or milliseconds?

If you need second-level accuracy, you can get a box that listens
to sattelite radio and gives you a serial feed.  Also, there are phone
numbers where people who have these boxes feed them into the phone.

For millisecond accuracy, you can use one of these lab I/O cards
with counter-timers.  You'll have to write your own device driver.

Lance

campbell@dataco.UUCP (Duncan Campbell) (06/06/91)

I suspect that the only solution to this problem will involve the 
introduction of new hardware.  Mebbe disect a high quality digital
clock and stick it on a card with a register that can be read
off the bus. 

Duncan



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