Re: Ext2fs and hashed table.

Rogier Wolff (
Mon, 9 Jun 1997 22:35:31 +0200 (MET DST)

> Hi,
> (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....


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