Article View: comp.os.msdos.programmer
Article #1753Re: INT 21 AX=5D06 Swap DOS data space call
From: Ralf.Brown
Date: Wed, 01 Aug 1990 14:17
Date: Wed, 01 Aug 1990 14:17
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In article <jbf6cm79f@tmsoft.uucp>, mshiels@tmsoft.uucp (Michael A. Shiels) wrote:
}Does DOS do it's own semaphoring with INT 2A AX=80xx/AX=81xx to ensure you
}don't swap in the middle of a drive read/write?
Not really. DOS protects a few sections of code that absolutely
positively cannot be reentered. Much of the SHARE.EXE code consists of
such critical sections--wouldn't want to interrupt the search whether a
file is currently open with an open of that file, would we? However,
DOS itself does not check the semaphores at all. That is left up to
whatever software is doing the reentering (that software also has to
maintain the semaphores itself).
--
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!wuarchive!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!tut.cis.ohio-state.edu!pt.cs.cmu.edu!b.gp.cs.cmu.edu!Ralf.Brown@B.GP.CS.CMU.EDU From: Ralf.Brown@B.GP.CS.CMU.EDU Newsgroups: comp.os.msdos.programmer Subject: Re: INT 21 AX=5D06 Swap DOS data space call Message-ID: <26b6e460@ralf> Date: 1 Aug 90 14:17:04 GMT Sender: ralf@b.gp.cs.cmu.edu Organization: Carnegie Mellon University School of Computer Science Lines: 17 In-Reply-To: <jbf6cm79f@tmsoft.uucp>