The Mudcat Café TM
Thread #40764   Message #585954
Posted By: JohnInKansas
04-Nov-01 - 08:25 PM
Thread Name: Help: computer problem
Subject: RE: Help: computer problem

PS: re defrag.

It's a good idea to close all files when you run defrag.

Defrag has to look at what's on your drive in order to decide what to do to it. It stores the "state" of the drive, to use while it's working. If anything on the drive changes, it has to start over.

ANY program that's open can "ding" the drive, and even the most minor change causes a restart.

If the drive is "disorderly" defrag itself may need to write a scratch pad on the drive - and this is a change, so it has to start over.

Usually - depending on drive size - nothing actually gets changed until defrag gets to somewhere around 8 to 12 percent. That's when it finishes "analysing" and actually starts moving stuff around. Screen savers are a particular nuisance, especially if set to come on after a short time. A defrag on a 20MB disk can be expected to take up to 3 or 4 hours, depending on machine speed.

Defrag will also refuse to function if the free (unused) space on the drive is less than about 10 percent, since it needs that much room to sort the files. Defrag picks up any file that's out of order and writes it to the "end" of the disk. Then it goes to the end of the disk to pick clusters up in order and write them back where they "should" be - in order.