Forums | MacLife

TechTool does it but I've been told that it's completely unnecessary.

Mac OS X uses something called "Hotfile Adaptive Clustering". The jist of this tech is that any file which is less than 20 megs in size is de-fragmented on the fly when it is accessed off the disk.

What about files larger than 20 megs? Well, i've only got 38 of them in my home directory, and they are all large media files which really never get modified, so their risk of fragmentation is fairly low.

In short, I wouldn't worry about defragmenting your hard drive.

How about iDefrag?

This caught my eye:

"Even if you aren’t interested in defragmenting your hard disk, if you produce products on CD-ROM disks, iDefrag will be of use. Seek times on CD-ROM and DVD-ROM disks are many times slower than those of hard disk mechanisms, so fragmentation really hits performance, in some cases adding many minutes to read times. iDefrag can defragment disk images before they are burnt onto CD or DVD-ROM, optimizing access time and significantly reducing install or read times."

Is that a legitimate argument in favor of this software, or hype?

mtpalms wrote:

How about iDefrag?

This caught my eye:

"Even if you aren’t interested in defragmenting your hard disk, if you produce products on CD-ROM disks, iDefrag will be of use. Seek times on CD-ROM and DVD-ROM disks are many times slower than those of hard disk mechanisms, so fragmentation really hits performance, in some cases adding many minutes to read times. iDefrag can defragment disk images before they are burnt onto CD or DVD-ROM, optimizing access time and significantly reducing install or read times."

Is that a legitimate argument in favor of this software, or hype?

A fragmented cd/dvd would be bad.  But I don't see how you'd get a fragmented disk image.  If you copy all the files to the image, each one gets copied in order, so the image won't be fragmented.

This makes no sense at all.

Think about it--as files are created, modified, moved, copied or deleted, space is needed in its new destination.  Likewise, when a file is deleted, the space it takes is vacant.  So, here comes a new file--look for an open block that the new doc will fit in.  It may fit in a heap of free space but there are also the instances where a file is too big and may have to be segmented such that it fits--partly in one area of free space and other portions of said file may have to be segmented up to fit in remaining free areas of the hard drive.  Just like a cupboard of cereal, soups, potato chips, etc.  A HD is just as vulnerable to scattering storage just as a file drawer or kitchen cupboard.

Over time, files are moved and jumbled around regardless of OS (Linux, OS/9, OS/X, etc.)

How is it then that the Mac is immune to fragmentation?  I am not convinced.  What makes the Mac OS so impervious to fragmentation?

http://docs.info.apple.com/article.html?artnum=25668

Yea, I'd usually agree, but my girlfriend's iBook is quite fragmented, and also only has 4.77GB available (I think I'll upgrade the HD this summer).

I can't find a free defragmenting program, and I don't really want to pay $30 for something I'll only use once a year (and I probably won't use it after I upgrade her HD).

Shadowless wrote:

Yea, I'd usually agree, but my girlfriend's iBook is quite fragmented, and also only has 4.77GB available (I think I'll upgrade the HD this summer).

I can't find a free defragmenting program, and I don't really want to pay $30 for something I'll only use once a year (and I probably won't use it after I upgrade her HD).

what if you upgrade her?

you can always put her book in TDM and copy all the stuff off of it, erase and re-install.

you would probably be better served with a good DU to take care of the directory more so than the defrag