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From: apratt@atari.UUCP (Allan Pratt)
Newsgroups: comp.sys.atari.st.tech
Subject: Re: 1024-byte floppy sectors?
Message-ID: <2964@atari.UUCP>
Date: 17 Jun 91 20:12:42 GMT
References: <3251@krafla.rhi.hi.is>
Organization: Atari Corp., Sunnyvale CA
Lines: 23

adamd@rhi.hi.is (Adam David) writes:
>TOS uses a BPB to handle various media specifications. The floppy driver /
>filing system must use 1024-byte cluster buffers for the standard format.
>Why should it not be possible with standard TOS to use 1024-byte clusters
>of one sector each? What modifications do I need to make to TOS in order to
>use the larger sectors with it?

>Any thoughts / suggestions welcome.

You are mistaken in your belief that TOS keeps cluster buffers around. It
doesn't.  It keeps SECTOR buffers around.  The floppy BIOS assumes sectors
are 512 bytes long.  GEMDOS does not, and hard-disk partitions larger than
16MB are implemented using large logical sectors (but not large physical
sectors) with appropriate values in the BPB.  To use 1K sectors on floppies
you would have to replace the floppy BIOS completely, and include in your
TSR a routine which replaces GEMDOS's sector buffers with new buffers large
enough to handle the largest sector size in your system.  This is what the
hard disk driver has to do (except that instead of replacing the floppy
BIOS it's installing the hard-disk BIOS).

============================================
Opinions expressed above do not necessarily	-- Allan Pratt, Atari Corp.
reflect those of Atari Corp. or anyone else.	  ...ames!atari!apratt