Re: how elevator algorithm works in modern hard disks?



forrest wrote:
On 1月22日, 下午7时37分, Josef Moellers <josef.moell...@xxxxxxxxxxxxxxxxxxx>
wrote:

forrest wrote:

Hi Everyone,
It's said that physical geometry is invisible to the cpu and is
unimportant. However, if the geometry is entirely different with the
logical one, which the cpu can see, how does elevator algorithm work?
As we know, elevator algorithm always find the nearest block in some
direction, which depends on the actual geometry of a disk.

Elevator algorithm is used in linux kernel, so there must be some
details that I don't know. Could anyone tell me?

Replacement strategies put aside, rotating disks are still organized in
cylinders, and even if they are of varying sizes (outer cylinders having
more sectors that inner cylinders), a higher sector number still implies
a higher or equal cylinder number.


Is there any reading material I can refer to? I want to know more
details about it.

Don't know, sorry.

--
These are my personal views and not those of Fujitsu Siemens Computers!
Josef Möllers (Pinguinpfleger bei FSC)
If failure had no penalty success would not be a prize (T. Pratchett)
Company Details: http://www.fujitsu-siemens.com/imprint.html

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