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SubjectRe: Ext2fs and hashed table.
Date
> 
> Hi,
>
> smurf@work.smurf.noris.de (Matthias Urlichs) writes:
>
> The main reasons that dump goes to disk directly are (a) to allow
> offline backup of unmounted devices, but more importantly (b)
> performance. Dump goes through the system in inode order, scanning
> blocks sequentially where possible, rather than going through the
> nearly random order that a directory scan would imply.

I find the "performance" thing questionable:

I once rewrote "fsck" (*) to do things efficiently. Instead of
doing things as they pop up, the "queue" of things to do was sorted
by block number. The whole fsck would be done in 5 passes through the
queue. (So the head would only do about 5 passes from block 0 through
the higher numbers....)

The result was about 10 or 20 percent faster than the "default" fsck
that didn't do the ordering right. I gave up then....

Roger.

(*) minix fsck, on Minix....

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