Ignore tips that say your Mac doesn't need defragmenting

I was browsing the web today and came across a tip for the Mac: "100 Tips #28: How Do I Defrag My Mac?" The answer was, "You don’t. There’s no need to. The OS X filesystem is designed to look after files properly in the first place, so that’s one thing you don’t have to worry about." Well that's just nonsense and my tip is to ignore tips that tell you you don't need to defragment your Mac's hard disk drive. The Apple Mac's file system is good, but it is not that good and it does not eliminate fragmentation. One of the reasons Macs get slower as they get older is because file fragmentation builds up. If you don't believe me, here's how to check.

Go to Coriolis Systems and download the demo version of iDefrag. It won't defragment your Mac's hard disk drive (unless you buy the full version), but you can use it to analyse the disk and display a report on the fragmentation. I just tried it and here are the results:

As you can see, there's a file with 893 fragments, a couple more with over 500 and so on. Is this utility simply lying and displaying fake messages to get you to buy the software? No, you'll find other utilities if if search for them and they'll tell you the same thing. Files get fragmented on the Mac. It's a fact. Here's another view of the fragmentation analysis:

The strip along the bottom is a graphical display of the files on the disk and the red lines are the fragmented ones. Seems to me that there's quite a lot of fragmentation there.

Fragmented files are slower to access than contiguous files in which the contents are stored as a single block on the disk. That's why a Mac with a heavily fragmented disk runs more slowly than expected. Defragmenting the disk will speed it up.

This is well known of course, and OS X keeps track of key files and tries to prevent them from being fragmented, but it's fighting a losing battle and it can't automatically defrag every file. It just leaves many to get fragmented.

So what can you do? One thing would be to buy a disk defragmenter like iDefrag. There are others, usually as a component of a utility toolkit like Drive Genius. Another way is to use a free program like Carbon Copy Cloner to copy the Mac's disk to a USB disk, then wipe the internal disk and copy the USB disk back to the internal one.

Of course, you could simply ignore fragmentation. Disk drives are getting faster it takes less time to find file fragments than it used to. I remember my first hard disk drive, it was 20Mb. Yes, that's 20 megabytes not gigabytes! I benchmarked the read speed and it was 90k/sec! At that rate it took all day to load a fragmented file!