Re: RFC: disk geometry via sysfs

[Phillip Susi <psusi@cfl.rr.com>]

linux-os (Dick Johnson) wrote:
> I read it, and it's wrong. You don't bother to learn. I will
> take one last hack at this and then drop it.
>
> When a disk is first accessed, the BIOS reads the disk capacity.
> That's all. This disk capacity is in 512-byte things called "sectors".
You don't bother to mention HOW it is wrong, so it appears it is you who 
fail to learn.  I will attempt once more to explain.  When you call int 
13 and ask it for C = 3, H = 4, S = 5, exactly which sector you get 
depends very much on what the bios thinks the geometry of the disk is, 
because the bios will translate 3/4/5 into a completely different value 
before sending it to the drive.  That translation is dependent entirely 
on which fake geometry the bios chooses to report the disk has.
I illustrated this translation and you simply say it is wrong.  If that 
is the case then show how.


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