How Does Hard Drive Fragmentation Occur?

Reich Web Consulting
Jul 31 · 4 min read

Note: This article was originally written on Reich Web Consulting has narrowed its focus to the web and no longer offers tech support services, so we’ve moved all of our tech support content off-site. We hope you find this article useful. It is provided as-is, and we will no longer provide support on this topic.

In my previous article, I explained what the term fragmentation means. But how does it happen? Fragmentation occurs when your computer saves parts of a file to multiple locations on your hard drive.

Fragmentation is Caused by the way your Computer Saves Files

Fragmentation can occur in several situations. Sometimes a file that needs to be saved is too big to fit in any of the empty spaces on a drive (a large movie file might be an example). It can also occur when you update an existing file and the space it already occupies isn’t large enough to accommodate the changes. The file system-the part of the operating system which controls how files are stored-has to make quick decisions about where it stores your data, and sometimes the fastest way to store it is by breaking it into smaller chunks. ( Reference)

This is how most file systems in the Windows world work, and it’s also why I said in my last post that fragmentation is a necessary evil. Other operating systems store files in a way that doesn’t cause fragmentation, but if you want to work on Windows it is a pain you’ll have to deal with for now.

Why You Should Care About Fragmentation

Fragmentation eventually causes your computer to slow down. It forces your hard drive to work harder than it would if files were organized efficiently, and if your hard drive is working overtime then in theory it could wear out faster than it would under more ideal circumstances. When data is spread across multiple locations, the drive has to cover more physical distance to retrieve it than it would if the file was stored as a single, continuous block of data. When too many files become fragmented, you’ll begin to notice a decrease in your computer’s performance.

Returning to the running metaphor I used in the last article, think about the work routine of the lazy librarian. As books are returned she puts them in the closest or most convenient bookshelf with no regard to the arrangement of the Dewey Decimal system. She might have saved herself some time up front, but when a patron wants to sign out one of these misplaced books she’ll have to work quite a bit harder to find it. The file systems of all Windows operating systems work with a similar lack of foresight.

How You Can Tell If Your Drive is Fragmented

The easiest way to determine if your drive is suffering from fragmentation is to use the analysis mode of your defragmentation program, which I will talk about in detail in my next article.

But you can often tell your drives are fragmented simply based on your computer’s performance. Fragmentation affects the time it takes to open and save files, not just for you but for your operating system and other applications as well. You might find that your files open slower when you select one through an “Open” or “Save” menu option. You might find that your computer takes longer to boot because files used by your operating system have become fragmented.

One application in which fragmentation seriously degrades performance is antivirus. This is because antivirus applications scan every file on your hard drive, and fragmentation of any of those files will increase the time it takes to open and scan them. Defragmenting (also called defragging) a drive before scanning it for viruses or spyware can decrease the time it takes to scan by an average of 44%. That’s a difference of 1.5 hours versus 50 minutes! Obviously fragmentation needs dealt with to keep your computer running efficiently. ( Reference)

What You Should Do About Fragmentation

Now that you know how your files become fragmented and you’ve accepted that fragmentation is unfortunate but unavoidable, you’re probably wondering how to fix it. The short answer is to run the defragmentation program that came with your operating system. The longer (and better) answer is to wait for the next installment of my discussion about fragmentation! I know, I’m such a tease.

Originally published at

Reich Web Consulting

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Purveyor of fine web creations. Former tech support geniuses. Occasional spouter of opinions on topics of politics and ethics.

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