Cylinders versus tracks...

Jules Richardson julesrichardsonuk at
Fri Dec 22 17:13:50 CST 2006

Tony Duell wrote:
>> Personally I prefer to talk in terms of 'surface number' rather than 'head 
>> number', as a given surface could conceivably have more than one head in order 
> Well, if I had a drive with, say, 2 surfaces, 2 heads per surface, and 
> 100 positions those heads could be moved to, I'd probably call it 100 
> cylinders, 4 heads, since logically it's the same as 4 surfaces with one 
> head per surface. Calling it 200 cylinders, 2 surfaces, while correct, 
> would seem to be as confusing as clalling it 400 tracks

Hmm, that's interesting. I suppose it depends on whether those multiple heads 
are referenced independently, or whether they're only there to improve latency 
(and hence from an interfacing point of view you still only reference two 
surfaces, but the electronics are smart enough to 'use' the head which happens 
to be nearest to the data that you want)

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