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From: zeus@zapodid.aero.org (Dave Suess)
Newsgroups: comp.sys.ibm.pc
Subject: wall-time creep under MS-DOS?
Summary: any fix?
Keywords: time() speeds up; interrupts
Message-ID: <47445@aero.ARPA>
Date: 13 Mar 89 23:43:06 GMT
Sender: news@aero.ARPA
Reply-To: zeus@zapodid.UUCP (Dave Suess)
Distribution: na
Organization: The Aerospace Corporation, El Segundo, CA
Lines: 12

I have a realtime application using a PC clone under MS-DOS -- it uses
the 18 Hz interrupt to run a closed-loop servo.  The software is in C,
and part of it needs (and displays) local time (using the appropriate
compiler library calls -- Turbo C, in this case).

After a few weeks running, the date advances by several days!  Is this
related to interrupts, system calls, or what?  I can't duplicate it on a
more recent system, and a colleague tells me he's seen this problem written
up somewhere... I'd appreciate any pointers anyone can give me (the end 
result will be saving $$ for taxpayers, if that's any excuse).
			Dave Suess	zeus@aerospace.aero.org
					...!trwrb!aero!zeus