[techtalk] partitioning question

[Almut Behrens]

On Wed, Jul 25, 2001 at 01:41:28PM -0400, Andrew Wendt wrote:
> On July 25, 2001 03:29, coldfire wrote:
> > so assuming that the extended partitions are in fact one big linked
> > list .. must that linked list be traversed from the very beginning to find
> > a specific partition down the line?  if so, that would be terrible for
> > performance .. needing to access hda342 but having to start on hda4 (yeah,
> > i exagerated a bit :).
> 
> The extended partitions are stored in a linked list, but the list only needs 
> to be read once and is thereafter remembered by the kernel.

... performance issues with several hundred partitions seem a bit
academic to me ;) but anyway: the kernel not only stores the partition
list in memory, it also isn't stored as a linked list, but as a linear
array, essentially indexed by minor number of the respective device.
I.e., there are no performance issues depending on the number of
partitions.
Also, AFAIK, with current kernels, there is a maximum of 15 partitions
per device for SCSI disks, and 63 partitions for IDE drives -- so, even
if you wanted to have 342 partitions, you couldn't ;)

Cheers,

- Almut