Cylinders versus tracks...

Brian L. Stuart blstuart at
Fri Dec 22 11:24:40 CST 2006

> Oh, that's another thing - is there a correct convention for track numbering? 
> There seem to be equal numbers of apps out there which treat the first track 
> as track zero as there are which treat it as track one :-) (Personal 
> preference would be to number from zero, just because it likely makes some 
> programming calculations easier, but I'm not sure if it's technically wrong to 
> present that visually to the user...)

I'm not sure there is a correct convention.  I do know that controller
programming can be a bit weird.  The old AT-style controllers on PCs
seemed to want the cylinders and heads numbered from 0 and the
sectors numbered from 1.  I don't have any hardware docs with
me at the moment, but that's what I've seen in drivers.  As an aside,
it's fun to try to explain to a class who've only seen sanitized classroom
examples that the real world is filled with stuff like this.  That's why
I like to teach OS with code, and not just general principles.


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