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From: borton@fwi.uva.nl (Chris Borton)
Newsgroups: comp.protocols.appletalk
Subject: Re: Does AppleTalk checksum packets?
Message-ID: <455@fwi.uva.nl>
Date: 23 Feb 90 12:58:48 GMT
References: <1990Jan27.015510.6906@phri.nyu.edu> <898@panix.UUCP>
Sender: news@fwi.uva.nl
Lines: 35

alexis@panix.UUCP (Alexis Rosen) writes:

>I seem to be seeing this myself. In particular, on a dedicated AppleShare
>server servicing AFP calls from multiuser databases, I've seen database record
>get trashed, so that they look like full 8-bit ASCII garbage. I've seen this o
>two separate networks, one LocalTalk, and one mixed LocalTalk/EtherTalk. It
>seems to occur more on the mixed network (dozens of bad records instead of
>three, across a three-week period). I can't believe that the database is
>responsible for this.  If it were writing stuff out of a bad pointer in
>memory (the only way the DBMS could be responsible, I think), I wouldn't
>occasionally see a dozen or so bytes or good data mixed in with the bad. It is
>possible (though not confirmed) that the damaged records were the subject of
>AFP locking contention.

This might possibly be related to the problem I reported months ago with
MPW Projector over EtherTalk.  We were having problems with source files not
coming back the same way they went in, and doing it twice in a row did not
result in the same file.  This was occurring only over EtherTalk; LocalTalk
didn't do this at all.  It also *seemed* to make a difference which volume we
used.  All very strange stuff with way too many variables to trace down in a
sane fashion.

The files would generally be almost whole, except for 2-5 lines either
missing (between random character locations) or garbage.

I received a note from a fellow at Kinetics when I posted about it saying
that he had seen some strange stuff like this too, but was simialarly
mystified.

The problem has been reported to Apple a couple of times but we have received
no repsponse on it.

-cbb
Chris Borton	borton@fwi.uva.nl
Mac Developer & AppleTalk Network Administrator, University of Amsterdam CS