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Path: utzoo!mnetor!seismo!rutgers!cbmvax!carolyn
From: carolyn@cbmvax.cbm.UUCP (Carolyn Scheppner CATS)
Newsgroups: comp.sys.amiga
Subject: Re: Disk cache
Message-ID: <1961@cbmvax.cbmvax.cbm.UUCP>
Date: Mon, 1-Jun-87 18:15:21 EDT
Article-I.D.: cbmvax.1961
Posted: Mon Jun  1 18:15:21 1987
Date-Received: Wed, 3-Jun-87 04:41:18 EDT
References: <333@rocky.STANFORD.EDU>
Reply-To: carolyn@cbmvax.UUCP (Carolyn Scheppner CATS)
Organization: Commodore Technology, West Chester, PA
Lines: 34

In article <333@rocky.STANFORD.EDU> rokicki@rocky.STANFORD.EDU (Tomas Rokicki) writes:
>
>I can handle everything off the top of my head but the intercept of
>the trackdisk.device calls, which I've never done before.  Perhaps
>someone would like to help me with this?

  See my Cmd.c/Cmda.asm posted here a few days ago for an example of
  SetFunction()ing some of a device's function vectors.

>Are there other programs which intercept AllocMem that I should be
>careful of, so I don't step on their toes?

  YES!  You must be very careful when using SetFunction() and especially
careful not to uninstall yourself if YOUR vectors have since been
replaced by another program.  Again, see Cmd.c for an example of
safe de-installation of SetFunction()'d vectors.  Otherwise, if more
than one program has SetFunction()'d the same vector, the original
true vector can be lost if de-installations are done in the wrong
order.  The code insures that de-installations are done in the
reverse order of the installations.

  The de-installation code is by Andy Finkel and was written for an
important program that SetFunction()s both AllocMem() and AvailMem().
The program is NoFastMem which will appear on the A500/A2000 Workbench.
It is used to temporarily force all memory allocation and availablity
requests to CHIP so that people with internal FAST ram will still be
able to load and run programs that are not written properly for FAST ram.

-- 
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Carolyn Scheppner -- CBM   >>Amiga Technical Support<<
                     UUCP  ...{allegra,caip,ihnp4,seismo}!cbmvax!carolyn 
                     PHONE 215-431-9180
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