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Article #4043Re: Serial line TSR - help needed please?
From: Frank van der Hulst
Date: Tue, 25 Dec 1990 09:44
Date: Tue, 25 Dec 1990 09:44
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1342 bytes
In article <6517@crash.cts.com> alen@crash.cts.com (Alen Shapiro) writes: >A friend of mine is having REAL trouble writing a TSR that reads a serial >port (at interrupt time) and stores chars in memory until a NL is read, >when it dumps the line to a file. The data rate is 300 baud max and >max 80 char lines are received no more than once every 3 mins. His major problem is how to write stuff to the disk -- DOS is *NOT* reentrant so he shouldn't write to the disk if some other application is currently calling DOS. There are several ways round this: catch all calls to DOS, setting a flag on entry and exit, or else latch onto the DOS idle interrupt (INT 28h, I think) which is called by DOS when its OK to call DOS. > > >
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Path: arc1-ca.pugleaf.net!utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!clyde.concordia.ca!thunder.mcrcim.mcgill.edu!snorkelwacker.mit.edu!paperboy!think.com!samsung!cs.utexas.edu!uunet!comp.vuw.ac.nz!cavebbs!frank From: frank@cavebbs.gen.nz (Frank van der Hulst) Newsgroups: comp.os.msdos.programmer Subject: Re: Serial line TSR - help needed please? Keywords: serial TSR how nasty DOS stuff Message-ID: <1990Dec25.094443.4925@cavebbs.gen.nz> Date: 25 Dec 90 09:44:43 GMT References: <6517@crash.cts.com> Organization: The Cave MegaBBS, Public Access Usenet, Wellington, NZ Lines: 21