[SLUG] Fedora Core 2 and X

[Gavin Baker]

Stephen wrote:

> If anyone knows how on earth I can get my logitech optical scroll 
> wheel mouse's scroll wheel to work then I'll be impressed btw!
>
Try adding

  Option      "ZAxismapping" "4 5"

to your to your mouse' InputDevice section and/or changing its Protocol 
to ImPS/2.

X should have set this up by itself really. The newer X's can autodetect 
most things.

> Oh, and why do ext2 file systems not need defragmenting like FAT/NTFS 
> then?
>
It does fragment, but usually not to the point of decreasing performance 
to any noticable level.

It's just the way it tries to allocate space. If you create a directory, 
it tries to allocate an inode for it that has plenty of free space in 
the same blockgroup etc.

It makes sense really; try to put files that are logically close 
together, (like a directory and it's contents) physically close 
together.... If you look at kernel-source/fs/ext2/ialloc.c, the 
functions find_group_dir and find_group_orlov have good explanatory 
comments of how it tries to do this.

It doesn't always suceed of course, especially when a file system is 
just-about full.

There are defrag utils for ext2. But it seems reasonable to assume that 
once you have defragged, new files *would* cause a perfomance decrease; 
if we place everything in our current filesystem in one continuous 
region of disk it would speed up reads, but any new file is going to 
cause a large seek, and quite possibly a huge one.

Regards,
Gav