> Any good SCSI drive knows the physical geometry of the disk and can
> therefore optimally schedule reads and writes. Although necessary features,
> like read queueing, are also available in the current SATA spec, I'm not
> sure most drives will implement it, at least not very well.
>
> So, what if one were to write a program which would perform a bunch of
> seek-time tests to estimate an IDE disk's physical geometry? It could then
> make that information available to the kernel to use to reorder accesses
> more optimally. Additionally, discrepancies from expected seek times could
> be logged in the kernel and used to further improve efficiency over time.
On a system that's been set up with one large root partition, and
nothing else, you might get a noticable gain, but I would guess that
you could get a simliar gain by partitioning the disk and manually
placing, E.G. /var near the outside of the disk, and things like /etc
near the centre. I.E. placing more active partitions on faster areas
of the disk.
> If it were good enough, many of the advantages of using SCSI disks would
> become less significant.
Not really - there are still a lot of advantages of SCSI that it
wouldn't address.
John.
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This archive was generated by hypermail 2b29 : Tue Apr 15 2003 - 22:00:28 EST