Path: utzoo!mnetor!uunet!lll-winken!lll-tis!oodis01!uplherc!sp7040!obie!wes
From: wes@obie.UUCP (Barnacle Wes)
Newsgroups: comp.sys.atari.st
Subject: Re: Turbodos and the ideal disk cache
Message-ID: <206@obie.UUCP>
Date: 1 May 88 19:05:37 GMT
References: <8804282151.AA29462@orville.nas.nasa.gov>
Organization: Great Salt Lake Yacht Club, north branch
Lines: 22
Summary: Yes, you can grab the hard disk read/write call...

In article <8804282151.AA29462@orville.nas.nasa.gov>, rowley@ORVILLE.NAS.NASA.GOV (Karl Rowley) writes:
> I have a couple of programming questions related to building a hard disk cache.
> 
> To build such a cache at the rwabs level, what is the cleanest to do it?
> Intercepting all BIOS traps and looking for rwabs calls would be one way.

It would slow down ALL BIOS calls as a side-effect.

> My MWC manual lists a variable named "hdv_rw" under System Variables.  This
> variable is said to point to the hard disk read/write routine.  Does anybody
> know what parameters the hard disk read/write routine expects when called?
> Is this routine used by all calls to rwabs?

Yes, this vector is used by all (GEMDOS) reads/writes from/to the hard
disk.  The easiest way I know of to find out how the `rwabs' call
works is to look at the source for Moshe Braners original ramdisk
program for the ST.  Is that still available on the net?  I've got an
extensively-hacked copy of it around here somewhere....
-- 
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