It reads and checks and realigns all your memory bits. It is much like removing articles off of a shelve and dusting them off and dusting the shelve off and placing the pieces back on the shelve all nice and clean.

i don't mean to call your data trash but i relate it to the way a trash compacter aligns all the stuff at the back so the front is blank for wild magnetic scribbling/short hand that will then later be compacted towards the back next time you defragment

the way it was explained to me was say you had an empty book shelf, this is your hard drive. you put books on it but you put them all over the book shelf, instead of starting in one place and putting the books next to each other. when you defragment, you pick up each book and re arrange them so there are no spaces between them.

It collects all the fragments of files and odd bits of rubbish and puts it all together freeing up all the clear space. This makes the computer find files much faster and work faster overall.

It tidies up. If you were reading a book but pages 86 and 87 were still at the library, you'd have to waste a lot of time going to get them. When you save your files to your hard drive they take up the first bit of free space so one game or program could be in little fragments all over the place, and your hard drive has to go through everything you've got on it, to find them all, every single time. When you defragment, you take all the fragments of a program and stick them all together in one place so the computer doesn't have to go searching, and it all runs a tiny bit faster.

Honestly,I don't understand it much but I know things run faster after you do. I use Linux though and I've never defragmented cause I don't know how on Linux or if it's necessary.

It re-arranges files on your computer, so it can run tasks faster by running in a less cluttered path, so it doesn't have to move back and forth to find files that run a program. Consider it cleaning your room to find a set of keys, it's easier to find stuff when you know where it's all at.

It's like taking all your paperwork that you've acquired over time and thrown into a box, and sorting it all into your filing cabinet. As you use your computer it throws data where ever it has a free or rewritable space on the hard drive. When you defrag it sorts all the data that's been 'thrown' and organizes it into complete files for faster retrieval yo...

My understanding is the hard drive gets the information laid down in a haphazard manner, so it is not organized which is called fragmented. the defrag program lines up all the data so it is concise and organized. when it is organized, the computer can access the information quicker so the system runs faster.

De fragmenting allocates contiguous memory spaces, thereby orders all files in continuous locations. Also, it groups similar files together allocates new indexing(if you have enabled them) after relocating the files.

Well, when your computer writes to the hard drive it places the data wherever it can as the write head zooms by. When you defragment it takes all this jumble and places it contiguously. Meaning that files have no breaks in them nor pieces of other files. It's like taking a messy photo album and placing all the photos from one occasion by eachother instead of all throughout.

The equivalent of cleaning up a cluttered, untidy desk or table: you get rid of rubbish, sort and organize the essentials, freeing up space, so you have a clean, free area to work on/with.

New angle on explaining defragmentation. I hope this works. I'm going to use numbers to represent file pieces. 1-9 will be one file, 10-19 a different file, 20-29 another, etc. I'll also use 00 to label empty space. File pieces are written to the drive in consecutive order at first, filling all the empty spaces as they go. So a hard drive with 5 files (of varying sizes) stored neatly would look like: 1/2/3/10/11/12/13/14/20/21/22/23/24/25/31/32/41/42/43/00/00....... In that example, there are 5 files and their pieces are contiguous. Now let's delete the 4th file (31/32) and we're left with: 1/2/3/10/11/12/13/14/20/21/22/23/24/25/00/00/41/42/43/00/00..... With me so far? Now let's add a new file made up of 4 pieces: 1/2/3/10/11/12/13/14/20/21/22/23/24/25/51/52/41/42/43/53/54/00/00..... This new file is fragmented, because all of its pieces don't fit together. This happens a lot on your computer. Every time you un-install a program, delete files, surf the web, this kind of thing happens on a grand scale. So after a while, the hard drive has more work to do to access certain files and this also slows things down. Defragmenting the last example would make the files line up like so: 1/2/3/10/11/12/13/14/20/21/22/23/24/25/41/42/43/51/52/53/54/00/00..... Ultra-simplified, but I hope that makes sense.

It removes the unused spaces between bits on the hard drive. Deleting things leaves usused spaces and programs end up in bits and pieces all over the drive. Defragmenting moves them all together and the computer doesn't have to waist time searching for pieces. If the drive is badly fragmented, new programs end up written all over the hard drive After defragmenting everything is in one continous binary word. Solid State hard drives don't require this to be done.

Defragmenting your computer actually rearranges your files stored on a disk to occupy contiguous storage locations. Thus it improves system startup times.