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Mail Archives: opendos/1997/04/23/08:30:50

Date: Wed, 23 Apr 1997 14:26:51 +0200 (MET DST)
From: Mark Habersack <grendel AT hoth DOT amu DOT edu DOT pl>
Reply-To: grendel AT hoth DOT amu DOT edu DOT pl
To: "Alaric B. Williams" <alaric AT abwillms DOT demon DOT co DOT uk>
cc: Matthias DOT Paul AT post DOT rwth-aachen DOT de, opendos-developer AT delorie DOT com
Subject: Re: Usage of directory entries
In-Reply-To: <861739004.1127939.0@abwillms.demon.co.uk>
Message-ID: <Pine.BSI.3.96.970423142220.12655I-100000@hoth.amu.edu.pl>
Organization: PPP (Pesticide Powered Pumpkins)
MIME-Version: 1.0

On Tue, 22 Apr 1997, Alaric B. Williams wrote:

> > > Fragmentation can be solved by moving fragmented files (found when the filer
> > > notes that accessing a certain file has entailed a lot of extent seeks) into
> > > contiguous areas from time to time, a sort of background defrag that works
> > > on individual files when it feels the need.
> 
> > Slooow! It seems really slow!
> 
> Mark thinks all my ideas will be really slow! Peasant! Grr!!! (Only
> joking - best of friends really :-)
;-))) I'm only trying to find all the week spots (whether really existing or
just imagined) beforehand. Being a sceptic may sometimes be useful -
especially in computer stuff ;-)

> Seriously, stop and think about it. The defrag thread can run purely 
> in idle time, ie it's at a REALLY LOW priority. OTOH, it sits there
OK. So it has a low priority and, as such, runs last of all the processes. Now
think about a situation when this defrag task is being pushed back to the
bottom by other ones which constantly mess with some files (say mkisofs, for
example) - that way the defragmenter is either not run at all or its work is
wasted everytime the file system is written with the huge amount of data
output from mkisofs?

 > invisibly sorting the disks out - so disk access is FAST and NICE!
> What's more, it might find disk errors and things while it's at it,
> and raise suitable alerts.
I agree here - the error detection would be nice. But, IMHO, it would be hard
to make the defrag work in concert with swapfile managers and caches. I don't
know... just my opinion...

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