Path: utzoo!attcan!uunet!husc6!rutgers!rochester!pt.cs.cmu.edu!b.gp.cs.cmu.edu!ralf
From: ralf@b.gp.cs.cmu.edu (Ralf Brown)
Newsgroups: comp.sys.ibm.pc
Subject: Re: DOS "Critical Section Flag"
Message-ID: <5368@pt.cs.cmu.edu>
Date: 30 Jun 89 01:00:16 GMT
References: <23020@santra.UUCP> <353@val.UUCP>
Organization: Carnegie-Mellon University, CS/RI
Lines: 18

In article <353@val.UUCP> ben@val.UUCP (Ben Thornton) writes:
}c37189h@saha.hut.fi writes:
}
}>Someone wanted to know when it is safe to access dos. (I think it was in this
}
}Actually, I think the only SAFE thing to do is intercept Int 21H and have the
}handler maintain a status flag.  Your routines that handle file I/O within
}your TSR can then test that flag.  I believe it is more reliable and less
}hassle in the long run.

Whether you use the INDOS flag or trap INT 21h, you will need to trap INT 13h,
INT 25h, and INT 26h to be entirely sure that no disk access is in progress
when the TSR tries to use the disk.
-- 
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