iDefrag

Hi Martin --

As a general rule, you really don't need to optimize or defragment your disk when you're running Mac OS X. Take a look at this KBase article that explains why. http://docs.info.apple.com/article.html?artnum=25668 As the article explains, there may even be some reasons why you wouldn't want to defragment a system running OS X.

That said, if you do a lot of video editing or other work on your computer that routinely swaps in and out huge files, a third party utility like iDefrag might be for you. I don't have any personal experience with that particular application, so I can't help you there.

-- JDee

I recently purchased this program to defrag my PowerBook G4. Everyone tells me I don't need to defrag, OSX has its own defragmenting routine, OSX's filesystem isn't prone to fragmentation and so on. But you know what? Defragmenting my hard drive makes me feel better. I sleep better at night knowing all my data is packed at the beginning of my hard drive. So I bought it.

Well, I like the application a lot. First of all, one thing you will notice right away is there is a lot of fragmentation on your hard drive. The application maps it all out for you before it begins. Once you start it up it unmounts the drive and goes to work (you will need to boot to a different volume to use it, I partitioned my hard drive and have Tiger on 75GB, 25GB to Panther for backup and for using iDefrag.

iDefrag works very quickly and has several different methods available for defragmentation. I have used it about six times so far, and have had no problems with it at all. That said, I don't really notice a speed difference or a performance difference. I look at iDefrag as preventative medicine. Over time, fragmentation would certainly affect performance. By using this application I believe I will prevent performance slow downs in the future.

And even if I'm wrong and it was a waste of 30.00, well it was only 30.00, and I am sleeping better knowing all my data is packed at the beginning of my hard drive.

PowerBook G4 15; 1.67 GHz; 512MB; 100GB; SuperDrive Mac OS X (10.4.3)

Hi Jeff,
Hi Martin,

" OSX has its own defragmenting routine,..."

Not exactly. What it does, is that it rewrites a complete file when it is used by an application. It does it all the time.
Defragmentation is like a side-effect, sort of.

That's just how Mac OS X works, and that's why
- of course iDefrag will always find that there is a lot of fragmented files
- it doesn't help trying to rearrange defragmented files at the beginning or at the end or in the middle... of the hard drive.

" ...at the beginning of my hard drive"

Mac OS X also chooses and arranges the best possible location on the hard drive, of the most often accessed files.
This best possible location depends on other kinds of criteria than the only beginning of the HD and than the only contiguity.

You can find some good info about this here:

(kernelthread.com) Fragmentation in HFS Plus Volumes
(TidBITS) Optimizing Disks Is a Waste of Time
(in addition to the
(Apple KB) About disk optimization with Mac OS X article)

That's why there is little benefit in defragmenting, it can even be counterproductive and defeat Mac OS X's own handling and rewriting of files on-the-fly, and don't forget that there is always a risk of System damage when getting so deep inside, if a power outage or something happens and interrupts...

In my view, there is more sense in doing an Erase & Install of Mac OS X, say once every year or two, and in rebuilding Directory twice a year with DiskWarrior.
Just my opinion.

Sleep well!
🙂
Axl