Do you like to spend time every month staring at your computer monitor watching those coloured block moving during hard drive defragmentation instead of leaving it alone doing its job ?
There's something "magnetic" that attract you to waste time in this way. Maybe it is a likeness that reminds you the things you liked (or still like ?)
Well.. i'm sorry to tell you that disk defragmentation is going to vanish as soon as new solid state disks will replace "old" hard disk drives (HDD).
The big reason fragmentation has a harmful effect on hard disk drives is because it forces the drive to do more physical work to retrieve the same amount of data. The read/write heads have to move back and forth that much more, and the system sometimes has to wait on the drive platters to spin all the more, which incurs a cumulative performance penalty.
In short, the reason fragmentation causes perceptible performance problems is because drives have moving parts (look at this video); they're not solid-state units, and they can't respond equally fast to every request for data.
The best recommendation for keeping HDD performance at an acceptable level is to "defragment" the HDD regularly. There are even some utilities (Diskeeper, for example) which continuously defragment the HDD so it never gets defragmented very much.
A Solid State Disk (or Solid State Drive) is really different: while not technically disks, the term Solid State Disk (SSD) may be used because they are going to be used as an alternative for disk drives (Samsung recently announced that it has developed a 1.8"-type 64 Gigabyte SSD).
SSD have no moving parts. It takes an equally long time to retrieve any one byte of data as it does any otherâ€â€or, if there is a delay because files are fragmented on data locations that are apart from each other, it's not something that is cumulatively measurable or perceptible to you. If a file gets fragmented on SSD device, it takes no measurably greater amount of time to retrieve it than if it is contiguous: it takes much less time for an SSD to electronically change the memory address to the next cluster in a file than it does for an HDD to move the heads and wait for the cluster's sectors to rotate under the head. You will hardly ever need to defragment an SSD. If it makes you feel better, you could do it once a month to eliminate cluster fragmentation, but you will not notice any good effects.
Then there's the question of what "contiguous" means on SSD devices because they use wear-leveling strategies, which places an additional layer of abstraction between the data and how it's organized. This is done to keep the number of read/write cycles for any given block of memory from being prematurely exhausted.
This is why talking about a given file as "fragmented" on a solid state drive is essentially meaningless; it could be stored by default in a number of blocks that are entirely disparate, and you'd never know.
