From:	CRDGW2::CRDGW2::MRGATE::"SMTP::CRVAX.SRI.COM::RELAY-INFO-VAX" 17-APR-1989 20:50
To:	MRGATE::"ARISIA::EVERHART"
Subj:	DMF synchronous driver problems under VMS-5.1,

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Date:     Mon,  17 Apr 89 20:07 +0200
From: Yehavi Bourvine +972-2-584279 <YEHAVI%HUJIVMS.BITNET@CUNYVM.CUNY.EDU>
To: info-vax@kl.sri.com
Subject:  DMF synchronous driver problems under VMS-5.1,

  I have an application that uses the DMF sync port (XG:) under character
oriented mode. This application worked ok under VMS-4.7; after the upgrade
to VMS-5.1 the system starts crashing a few hours after this application
is run. The crash usually happen when a rare subroutine is called, thus
probably causing paging. The crash dump says that the process runs at IPL
8, and the cause is exception above ASTDEL IPL. This gives me the impression
of paging problem. The peice of cose that executed at this time is an AST
called after the completion of reads $QIO for the DMF. As far as I understand,
this AST should run at IPL 0, not 8. Any ideas?
  Another thing that I think is not done right at the XG driver under 5.1 is
the locking of the buffers used for the current IO. Few of the crashes happend
when my process was not the current one. After locking all my buffers in memory,
this was cured, and from then the system crashes only when my process is the
current one, and in IPL 8.
                                 Thank you for any comment,
                                            __Yehavi:
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Yehavi Bourvine,             Phones: +972-2-584279,     H
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The Hebrew University of Jerusalem,  +972-2-521574      H
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