Text 1423, 56 rader
Skriven 2004-09-23 06:55:02 av Jasen Betts (3:640/1042)
   Kommentar till text 1392 av Paul Rogers (1:105/360.0)
Ärende: It did WHAT?!
=====================
Hello Paul.

22 Sep 04 09:42, you wrote to me:

 PR>> Be warned that what you're usually told about the order Linux
 PR>> assigns hdaX numbers is different than what you're usually told.

 JB>> whaich is what exaclty?

 PR> The Linux books I've been reading demonstrate an installation
 PR> where all the partitions are simply assigned in disk order,

that's what happesn if you define them in that order...

 PR> using fdisk or in some cases Disk Druid.  Then when they talk
 PR> about the mapping to hdaX, they don't make much of a point that
 PR> it's the order of assignment in the partition table, not on the
 PR> disk;

most told me to print the partition table out before saving it.
wouldn't that make it obvious?

 PR> Starting things at one end and going sequentially to the other
 PR> ISN'T the most efficient way of allocating disk space.

that depends how you measure efficiency.

 PR> If the main "directory" is first and you're equally likely to go
 PR> from there to a file anywhere on the disk, then the average seek will
 PR> be half the disk.

In the real world the root directory spends most of its time in ram, simply
because it's so often used.

 PR>  The maximum will be the full disk.  If, OTOH,
 PR> it's in the middle, then average will be one quarter, maximum
 PR> one half.  Disk caching does little to avoid seeks.  On IBM
 PR> mainframes we regularly put the Volume Table Of Contents in the
 PR> middle of the pack.

there's no rule that says you need to define the root partition first when
using fdisk, or that you need to define them in disk order.

 PR> Authors are often making a bad assumption that users have
 PR> built partition tables in disk order.

if that's what the author tells the user to do that, how is it a bad
assumption.

fdisk here asks me what number I want to give each primary partition I make
(but not each extended partition - hmm)

Jasen

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