What is Fragmentation?

An article by Brian Reich    5 Comments

Fragmentation is  one of the primary ailments that infects a slow computer.  You might have heard the word before. Someone might have even taught you how to fix it.  But most of us don’t know what fragmentation is, how it occurs, and–unlike a virus or spyware–why we’re stuck living with fragmentation in our lives.  Without getting into too many technical details, let me explain what fragmentation is.

According to it’s Wikipedia entry, fragmentation is the inability of a file system to lay out related data sequentially (contiguously).

Think of your computer’s hard drive as a library run by the laziest librarian in the world. The library’s founders organized it’s books according to the Dewey Decimal System but as books are returned and new books are donated to the library, the lazy librarian puts the books wherever she can find space for them, as opposed to placing them in the appropriate location according to the system.  After a while the lazy librarian as well as the library’s patrons will have to work much harder to find the books they need.

Your computer works in much the same way.  Your operating system has what is called a file system (a method for storing and organizing files) but, unlike the Dewey Decimal System, disorganization is often built into it.  Most file systems (including those used by Windows) will store chunks of a file wherever it can find space for them on the disk.  When you need a file your computer has to work harder to retrieve it because it is spread across different physical locations on the hard drive as opposed to being stored in a single, larger chunk of disk space.  This not only causes slower performance, but can theoretically shorten the life of your hard drive.

To fix file system fragmentation you use a utility called a defragmenter.  A defragmenter is the veritable Conan the Librarian of your hard drive: it corrals all of the chunks of each file together into a single continuous space. When a defragmented file is accessed after defragmentation, your computer doesn’t have to work so hard to locate all of it’s segments because they are all arranged in the same location. I’ll talk more about how to defragment in the follow-up article.