Roger C. Scudder Jr. on Sun, 25 Apr 1999 06:58:34 -0400 (EDT)

[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

RE: Linux file system

This is my take on this subject...

The reason FAT file systems need to be de-fragmented is because of the way
disk space is allocated.  A file may be split into several pieces and a table it 
recorded to keep track of where one section ends and the next begins.  That's
where the performance hit comes in.  If there are lots of files split into lots of
pieces the disk head starts spending a substantial amount of time positioning.

The reason all of this becomes necessary is because the disk space can only
be allocated in a linear fashion from front to back.  This causes problems when 
files are deleted there ends up being a lot of small free spaces.  Unless the 
splitting method is used  the front to back method is very inefficient.

In the case of the ext2 file system,  files need not be split because there is no
front to back allocation restriction.  Space is allocated in a scheme that greatly
reduces the number of small unused free spaces.  Imagine playing Tetris if
you didn't have to always work from the bottom up.  You'd get a lot more 
opportunities to arrange the blocks just right.

-----Original Message-----
From:	Steven J. Pulito []
Sent:	Tuesday, April 20, 1999 1:51 AM
To:	PLUG Mailing List
Subject:	Linux file system

Hello everybody,

quick question:

I've heard that there is no need to defrag a linux hard drive because the
file system does it automatically.  Could someone verify this and possibly
elaborate on the technical details?

Steve Pulito

To unsubscribe, send a message with the word 'unsubscribe' in the subject
or body of your message to

To unsubscribe, send a message with the word 'unsubscribe' in the subject
or body of your message to