Subject: Re: ccd performance
To: Hauke Fath <hauke@Espresso.Rhein-Neckar.DE>
From: Dave Huang <>
List: current-users
Date: 06/14/1997 17:43:37
On Sat, 14 Jun 1997, Hauke Fath wrote:
> I'm not even sure about that...
> The effective data rates of a 5400rpm and a 7200rpm disk need not
> necessarily differ that much. On the other hand, when you've reached the
> innermost cylinders of your 2GB disk, you are still not half through the
> 4GB disk. There are some drives (IBM's come to mind) that keep up maximal
> data rate for the entire outer half of the disk, so the two drives' data
> rates would differ by a factor of two or more. That's less for empty disks,
> though.

Yeah, my 5400rpm drive does have more sectors per track than my 7200rpm
one, although not enough more to make up for the difference in rotational
speed. Also, I'm only using about 800 megs on each disk for the ccd. In my
current setup, the ccd component on the 5400rpm disk starts on a cylinder
with 144 sectors/track and ends at 129 sectors/track (according to the
notch mode page thingie), which I guess would be 6480 to 5805KB/s. The ccd
component on the 7200rpm disk starts on a cyl with 132spt and ends at
114spt, which would be 7920 to 6840KB/s.

If I were to move the ccd component from the 5400 drive to the 4 gig 7200,
it'd probably span a section of the disk with 132spt to 124spt, 7920 to
7440KB/s. Not too bad, I suppose, much less of a speed difference than the
5400rpm drive.

But back to my original question... :) Anyone got suggestions on what sort
of interleave to use for ccds on zone bit recorded disks?

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