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From: wwtaroli@rodan.acs.syr.edu (Bill Taroli)
Newsgroups: comp.sys.mac.hardware
Subject: Re: Disk optimization
Message-ID: <1990Sep22.224137.27367@rodan.acs.syr.edu>
Date: 22 Sep 90 22:41:37 GMT
References: <1990Sep20.163033@miguel.llnl.gov>
Organization: Syracuse University, Syracuse, NY
Lines: 45

In article <1990Sep20.163033@miguel.llnl.gov> macq@miguel.llnl.gov (Don MacQueen) writes:
>together each in one big block.  But if this is done then the next time
>a file is made bigger it is necessarily fragmented.  Wouldn't it be
>better to take the free space and divide it up proportionally to the
>file sizes and stick a bit of free space after each file?  Then files
>would have a better chance of not becoming fragmented.

What you say is true. However, at least one disk optimizer, Disk Express II,
attempts to account for this. What it does is move all the files, in a
predetermined manner, to the _end_ of the disk. It then leaves all recently,
read "in the last couple days", used files at the head of the disk. It is 
designed to run nightly. Thus, if you were working on an old file whose size
grew, this file would be moved to the head of the disk. Presumably, if you edit
it, then you will have some interest in the file for a while... and will likely
edit it again. In this way, the situation you describe is avoided (or at least
you don't have to live with it for more than 24 hours).

However, some have criticized DiskExpress II because it can run during your
work. In older versions, this would actually occur during whatever you were
doing. As of 2.04, this problem has been solved somewhat by DiskExpress II
bowing out more easily if you are typing, mousing, etc. I haven't formed a firm
opinion on this, but have toggled the "Optimize Automatically" option many 
times.

It should be noted here that DiskExpress II will also allow you to have it
track your usage of files without performing automatic backups. This affords
you the option to have DiskExpress II perform the optimizations when _you_ want
in addition to putting the most recently used files at the beginning of the 
drive.

This is the only package I know that performs optimizations in this manner
(pushing older files to the end of the drive), but there may be others. This
just happens to be the one I use.

Regards,

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* Bill Taroli (WWTAROLI@RODAN.acs.syr.edu)    | "You can and must understand  *
* Syracuse University, Syracuse NY            | computers NOW!" -- Ted Nelson *
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--
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* Bill Taroli (WWTAROLI@RODAN.acs.syr.edu)    | "You can and must understand  *
* Syracuse University, Syracuse NY            | computers NOW!" -- Ted Nelson *
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