Just what exactly is taking up all of that disk space?

Anyone who is serious about committing their piles of paper and other media to digital format asks this question from time to time. And it doesn’t seem to matter how large hard drives have grown over the years—the media files seem to grow to keep pace quite nicely.

I would like to share with you a pair of similar free utilities, one for the PC and one for the Mac, that allow you to easily evaluate exactly where your disk space is going.

(This topic was recently discussed on the Mac Geek Gab podcast, which inspired this post.)

The Old Way

In the past I would often poke around the hard drive, checking out the “usual suspects,” occasionally finding a few plump temporary files or some stale unused applications that could be dumped. When I needed to do a more thorough cleaning, I would run a “find” for files larger than, say, 10MB, and I would sort them in descending order and hack away at the resulting list.

But I have never been satisfied with the results of my efforts—there has always been some lingering feeling that I just wasn’t seeing what the true space hogs were on my system.

Then I found an application that uses the concept of Treemaps to display your hard drive in a colorful visual form.

Treemaps

This is what a treemap of my Mac hard drive looks like:

The application has used color coding and rectangles to represent files on the hard drive in such a way that accentuates clusters of similar items.

Each directory is represented by some rectangular area in this image. The colors represent different file types (e.g. MP3 files), making it easier to spot large sets of similar files, and easier to visualize where your space is going.

For example, the thin yellow rectangle is highlighting the space (in blue) occupied by my iTunes music library. The large red area on the right (seen by the tool as a single file) is my iPhoto library. The area between those two sections is my current video recordings from EyeTV (in green), along with all of my text documents.

You can see quickly from this image that photos, video, and music occupy the lion’s share of my hard drive. Most of the remaining jumble across the bottom is the Mac OS X operating system and all of my program files.

At a glance, I can see that if I deleted all of my EyeTV recordings, I would free up a large percentage of my drive space.

It is through this tool that I realized how impractical tools like Xslimmer are for me. These tools save disk space by removing non-Intel binaries and unused language files (Mac applications often come with Intel and Power PC binaries packaged together). But even if I deleted my entire Applications folder, it would only free up a corner of the map above. I just wouldn’t gain much by slimming down application files and language resource files.

Since I work with both Mac OS X and Windows, I found a freeware version of this utility for each.

Disk Inventory X

This is the Mac utility that I used to make the screenshot above. Here is the application developer’s website.

Besides showing the treemap, Disk Inventory X provides a file browser tree and a sidebar with information about the color coding. You can bring up an Information pane that shows the details of whatever item you have selected in the treemap.

Again, I have selected my iTunes library. You can see in sidebar that blue means “MP3 Audio File.”

WinDirStat

This is pretty much the same application concept in an open-source version for Windows. Here is the developer’s web site. Scroll down to the bottom of their page for the download link.

In this screenshot from Windows, I selected my C:\Program Files directory. You can see the white rectangle on the right side, showing us exactly how much space all of my programs occupy.

Other notable features on this screenshot: my system page file is that fat bluish rectangle in the bottom right, and the collection of red in the upper left is a large quantity of Windows patches.

Summary

Both of these tools provide an excellent means of visualizing exactly where the fat is in your hard drive. The price is right. Try one today!