Fragmentation of a hard drive naturally occurs over time as you save files. To understand this think of files being built out of blocks that you number to keep track of the order. When you initially save them you put them in order (0,1,2,3,4,5,6). Then you save a second file it will save at the end of the first file (0,1,2,3,4,5,6,0,1,2,3,4,5,6). Now you open the first file, maybe it was a word document. When you save the document it grows in size and so now it looks like (0,1,2,3,4,5,6,0,1,2,3,4,5,6,7,8). Over time even the order of the blocks can be messed up (1,8,5,7,3,2,1,5,4,3,2,0,6,4,6). When the numbers (or documents) are out of sequence, it takes the computer more memory space and longer to find, open, and save the requested file and in extreme cases, may cause errors in loading the file(s).

Running a disk defragmenter will put the blocks back in order and make room so the blocks are one after the other (0,1,2,3,4,5,6,7,8,0,1,2,3,4,5,6).

NERD NOTE - Google does not allow animated GIF images to be displayed when using Google sites (the system this web page is written in). However, if you click on the image to the left the image will display by itself and will demonstrate how defragmentation operates.