Subject: Re: ccd performance
To: Brian Hechinger <>
From: Hauke Fath <hauke@Espresso.Rhein-Neckar.DE>
List: current-users
Date: 06/14/1997 21:36:15
At 18:38 Uhr +0200 14.06.1997, Brian Hechinger wrote:
>Hauke Fath drunkenly mumbled...
>> "Half of the 4GB disk" is about the outer third of the disk's cylinders.
>> With zone bit recorded disks, the physics of this area (spoken in terms of
>> data density/bits per inch and data rate/bits per second) is entirely
>> different from a full 2 GB disk. With a SCSI ZBR recorded disk you have *no
>> way* of accessing "half the heads" to mimic half the capacity as the
>> internal data layout is entirely up to the disk.
>hmm, hadn't thought of that.  yea, i guess it woulnd't be that easy.  but if
>he did do this he would get better results than a 5400rpm and 7200rpm drive
>right??  that is where we are headed here anyway.

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,

> i thought i was
>being witty and useful and trying to help, guess i didn't help all that much
>afterall. :)  (although i did learn something today, and that is always a Good



"It's never straight up and down"     (DEVO)