{ somewhat off topic, for the file system curious }
On Wed, 5 Jan 2000, Gustav Schaffter wrote:
> OTOH, OS/2 Warp uses HPFS, which was also said (by Microsoft !-) to keep
> defragmentation low and shouldn't need any defragmentation. Experience
> showed, though, that defragging an HPFS partition *could* make a
> difference. Primarily on partitions with static (or almost static) data
> residing on them.
HPFS tried very hard to avoid fragmenting files. The file APIs took an
optional parameter of file length, and used this to find a free space on
disk with enough space for the file; if not enough was available, it
looked for free fragments nearby each other to improve read
performance. When this parameter was not provided by the application, the
file system did its best. Since not all (in fact, very few) applications
used this feature, HPFS was prone to fragmentation, just not as prone as
FAT. Since most of us came from FAT to HPFS, this was still an amazing
improvement.
Most of the defraggers which were made were just programs which made a
copy of every file on the disk, providing its length to the file system,
and it let HPFS do its best. This worked suprisingly well.
Finally, for the interest, NTFS is a descendent of HPFS, and is basically
HPFS with security features added.
Rob, showing his OS/2 roots...
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