Defrag not working?

[BuzzStPoint]

I run the disk defrag on my wifes computer and it runs for about 20 minutes. Then it says the defrag is complete..

Then you analyize the drive and it tells me it should be defraged again.. Whats the deal with that?

Is the drive fairly full?

Two things come to mind:

1) the drive is fairly full(no warnings yet) but there is not enough space left on the drive to perform the defraging. Being at that spot may not show a warning that the defrag did not succeed but will show to have defraqed until you run defraq again and it suggests that you need to run it.

2)This one is dependent upon how your files are located on your drive.
There are usually one or two sections that contain unmovable files. During defrag the noncontiguous files are removed and relocated to make them contiguous. This means that the fragmented files are reassigned to where they should be in order to make them in the same section as other like files.

Picture files as an example( easier to picture like files[pun intended]):

you have lots of picture files before and after a non-moveable cluster of files. The defragmentation will remove the picture files and rearrange them accordingly. The problem is that there is not enough space in front of the non-movable files to place them all so the files are placed in front of and behind.....This causes the program to read it as still fragmented because the files are split with the non-movable files and are not contiguous to the filing system.

As an added note> it doesn't matter which defrag program is used when dealing with the issue of installing contiguous files in front of or behind a cluster of unmovable files. More powerful defrag programs will sometimes compact files to get them all in one area while windows defraq will not...but same situation will occur using any defraq program if it is dealing with a large contiguous file that is fragmented.

from M$:

Even if you perform a full optimization, the drive may not become 100% defragmented.
CAUSE
This problem occurs when there are unmovable blocks (clusters) on the drive and a movable file is made noncontiguous by one of these blocks. Defrag tries to fit files around the unmovable blocks so that the files remain contiguous, but it is not always possible to achieve a perfect fit.

In the following simplified example, the drive has only ten clusters and three files; file A has five movable clusters, file B has two unmovable clusters, and file C has two unmovable clusters:
.....CLUSTER: 1 2 3 4 5 6 7 8 9 10
----------------------------------------
...........FILE: A B B A A A C C A
----------------------------------------
......STATUS: O X X O O O X X O O

CLUSTER = The cluster number on the drive.
FILE = The file that occupies the cluster.
STATUS = O : MOVABLE X : UNMOVABLE

In this example, files B and C cannot be moved. Because there are not five contiguous, movable clusters on the drive, file A cannot be fully optimized and the drive cannot be 100% defragmented.

Although it appears you could work around this problem by making unmovable files movable, doing so is not a good idea. Many programs mark a file as unmovable because the program keeps track of the exact location of the file. Moving the file can cause the program it is associated with to fail. For example, some programs use unmovable files as part of a copy-protection scheme.

It is better to have a slight level of fragmentation than risk moving an unmovable file that should not be moved.

http://support.microsoft.com/kb/105068/en-us



edit> the example above should have lined up top to bottom for better view but didn't< sorry!

[BuzzStPoint]

Here's what it says

Capacity: 18.6gig
used; 9.77
Free: 8.86


Heres the odd thing.. I thought that this was a 20 gig harddrive.
She has a lot of mp3's and music videos on her computer.


Edit Stats
WIndows XP
NTFS

Could be either situation as stated above. But I bet it is the unmovable files issue. If possible work around the problem by creating seperate folders for some of the music videos as they are probably the ones that are causing the issue. If they are grouped in a folder take them out of the folder/grouping.

[SetiShock]

What's the model number on the drive?
And remember in the world according to uncle Bill> 1K =1024 bytes.
Throws you off when figuring drive space. It's there just configured like Bill wants it.

[domass]

Buzz,
Remember if you buy a hard drive that says 20 gig on the box, Windows will report it as 18.6 because the hard drive company counts a gig as 1000 MB and a MB as 1000 KB. Windows counts a gig as 1024 MB and so on. You know the binary thing. So if you take the 20,000,000,000 bytes that the hard drive manufacturer says there is on there and divid it by 1024, 3 times you will get 18.626.
Are you remembering to turn off everything you can while running the defrag?

[BuzzStPoint]

http://www.seagate.com/support/disc/...st320410a.html

Theres my drive
Seagate ST320410A

U Series 6

Capacity: 20.4 GB
Speed: 5400 rpm
Average Seek Time: 9.9 ms
Cylinders: 1023
Heads: 256
Sectors: 63

[BuzzStPoint]

domass.

That puts it clearer as for turning everything off no.. I can try that.. Cna I defrag in Safe mode?

[SetiShock]

The built in will. DK pro and 9 won't.