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From: jack@mcvax.UUCP
Newsgroups: comp.sys.atari.st
Subject: Why does GEMDOS call Mediach() so often?
Message-ID: <7359@boring.mcvax.cwi.nl>
Date: Wed, 22-Apr-87 11:05:39 EST
Article-I.D.: boring.7359
Posted: Wed Apr 22 11:05:39 1987
Date-Received: Fri, 24-Apr-87 02:59:58 EST
Organization: AMOEBA project, CWI, Amsterdam
Lines: 21


While testing my remote disk driver (soon to be posted), I noticed
that GEMDOS makes a *huge* number of calls to the Mediach() routine.

For instance, when doing a 'show info' on a (remote) hard disk, it
would do the calls rwabs, mediach, rwabs, mediach, mediach, mediach,
rwabs, 10(!) times mediach, etc etc.

It calls mediach at least once between reads, but often more. I saw it
being called *forty-seven* times in a row once.
Is there any reason for this behaviour? Is there anything I can
do against it? Should mediach() perform more functions than the bios
guide says (return 0/1/2 for not/maybe/definitely changed)?

Not that mediach() is usually a cheap call: just check a bit in the
hardware somewhere.
For a remote disk, however, it is quite expensive, since a packet has
to be sent back and forth.
-- 
	Jack Jansen, jack@cwi.nl (or jack@mcvax.uucp)
	The shell is my oyster.