Date: Sat, 22 Feb 1997 12:09:19 -0600 (CST)
From: "Colin W. Glenn" <cwg01 AT gnofn DOT org>
Reply-To: "Colin W. Glenn" <cwg01 AT gnofn DOT org>
To: "'OpenDOS newsgroup'" <opendos AT mail DOT tacoma DOT net>
Subject: Re: [opendos] BAD Filesystems
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On Tue, 18 Feb 1997 jdashiel AT eagle1 DOT eaglenet DOT com wrote:

> Why not add a crc on the file name; creation date, and creation time? 
> Perhaps a combined crc to act as a tie breaker but those must be and
> remain unique.  That as a random access key into a lookup table

If we use such an approach, then we could either use the method which
Linux uses, (if I understand what mharris is saying about Linux
installations in a dos FS), or when we have the driver install itself, it
would 'allocate' a file for itself to use, then hide and system it so it
doesn't get moved by defrag, and encode the absolute location of the file
into the driver itself.  Then whenever a dos-disk access is called, the
driver would trap the interrupt, update the file if necessary, then
proceed to dos for the actual execution of the command.  It would have to
be written in a very tight assembly language routine to minimize
overhead, but I think it can be had in as little as 50 instruction cycles,
not counting when the driver uses the BIOS for the disk access to update
it's control file.

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