[Linux-disciples] Defragging a Linux box?

[Stephen R Laniel]

I assume Linux filesystems need to be defragged just like any
other filesystem, right? Files get read and written out of
random blocks, leaving bits of files scattered all over the hard
drive. The disk head will have to move all over the disk to read
the file.

Is my reasoning correct? If not, what's different about ext2/3?
If so, which defragger do you use?

-- 
``I personally find it worrying that the administration's choices
  in domestic and foreign policy are starting to puzzle clever
  economists. These, after all, are people who by temperament and
  training will bend over backwards till their spines snap before
  saying the words, `Yeah, I guess you'd have to say that was
  pretty irrational.'''
 -http://www.crookedtimber.org/archives/001265.html