Mail Archives: opendos/1997/04/23/00:34:59
> > 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!
I have to agree. Win95 does that. Perhaps because the heads aren't left
near where they're most often wanted, or because FAT partitions never
get ver fast anyway. I'd prefer to have a filesystem that isn't so
subject to fragmentation so a defragger has little to do.
What I would like the system to do (as an option; if you have enough
RAM, etc) is to record what files are often needed after other files,
to sensibly preload or rearrange sectors.
I think the priorities should be:
(1) Decide on a system (lets call it IFS) to which filesystem-dependent
drivers can be added (with the least source changes from Linux the
better!) This should be able to be used on generic DOS (albeit with
some limitations) but certainly tie in with OpenDOS security.
(2) Start with at least ext2fs and vfat drivers for it.
(3) Invite others (especially commercial/shareware vendors of existing
hpfs, etc drivers) to write using it. Make sure the licencing
allows them to distribute the IFS with their product to help it
become popular.
(4) Design "automatic" diskette and CDROM drivers that adapt to the
media formats, e.g. detecting Macintosh diskettes. So the IFS should
start by doing a simple check "is this a valid FAT diskette", and
even "does this have a known virus signature or characteristics of
viruses?", then call each loaded driver until one recognises the
format.
(5) Design a totally new file system that requires very little RAM
yet is efficient (to be very efficient it might want more RAM), and
capable of storing just about any extended attributes, ACL
permissions, etc. If anybody wants to discuss details I have some
ideas (which I'd love to simulate, if anybody has flexible software
for the job).
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Mark Aitchison, Physics & Astronomy \_ Phone : +64 3 3642-947 a.h. 3371-225
University of Canterbury, </ Fax : +64 3 3642-469 or 3642-999
Christchurch, New Zealand. /) E-mail: phys169 AT csc DOT canterbury DOT ac DOT nz
#include <disclaimer.std> (/' "per haps ad gloria"
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