Originally Posted by gresch

only if the partition is in FAT, not NTFS

here's some info for everyone:

A blank unformatted disk is like a newly constructed parking lot with no lines.

Formatting puts the lines in and in those spaces, or blocks (the correct phrase) on a disk is where files are written. Blocks can vary in size and the size is determined by what the disk will be used for. For commone every day use like a home PC, a small block size is best as most files are small. On a machine that stores HUGE files, a bigger block size is best. Why? Because if you put a small file in a big block, whatever space that isn't used in the block is wasted (i.e. putting a 4k file in a 10k block wastes 6k or 60% of the space). Writing a HUGE file to small block sizes makes the disk work harder as it traverses all of those tiny blocks instead of doing a looooong read on a big block.

Another example: Say you've written 10 files to a disk and delete files 5 & 6 in the middle. The next time that the OS needs space to write a file it knows that the blocks taken up by files 5& 6 is available so it plunks all or part of the new file in that space. If the file is too big for the space, the OS writes a part of the file there, then seeks to a new spot and continues to write.

Why does this matter? Because now that new file is written all over the disk and to retrieve (open) it, the disk heads have to traverse all over the disk to get it.

What does defrag do? It reads the disk and puts all of those "fragmented" files back to together in 1 contiguous space so that when they are retrieved the drive does less work by reading the file from 1 place.

All of that being said, NTFS does a better job of not letting a disk get fragmented, while a FAT drive is usually a mess and needs to be defragged a lot.

*puts pocket protector away and continues on with day.

Have a nice day