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Increasing Storage Space on Boot/System SSDs for Mobile Devices

Managing free disk space on computers and devices is a bigger issue now than it used to be, thanks to the proliferation of 32-, 64-, and 128-GB solid-state drives (SSDs) as "typical" for low-end tablets and notebooks. Kim Lindros and Ed Tittel show you how to use the graphical disk analyzers WinDirStat and SpaceSniffer to free up space on disks, especially on SSDs where disk space is usually at a premium.
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Managing free disk space on computers and devices is a bigger issue now than it used to be, thanks to the proliferation of 32-, 64-, and 128-GB solid-state drives (SSDs) as "typical" for low-end tablets and notebooks. You can use Windows Explorer (Windows 7 and previous) or File Explorer (Windows 8) to check partition space and search for files by size, but we use a few utilities that provide value-adds and make this task much easier.

WinDirStat and SpaceSniffer run in any version of Windows, and each does a great job of inspecting and freeing up Windows disk space to optimize the performance of smaller SSDs. Both utilities are freeware, although SpaceSniffer calls itself "donationware" and appreciates contributions, large or small.


WinDirStat is an open source, graphical disk analyzer for Windows that provides usage statistics and cleanup functionality. A few Linux alternatives are KDirStat, upon which WinDirStat was created, and Baobab. Similar tools called Disk Inventory X and GrandPerspective are available for Mac OS X.

To use WinDirStat, download the windirstat<version>setup.exe installer file and double-click it to start the installation. WinDirStart starts automatically.

Upon launch, WinDirStat prompts you to select whether to scan all local drives, an individual drive, or a specific folder. The program then reads the directory tree (within a minute or two, depending on the size of the disk) and presents the information shown in Figure 1.

Figure 1 WinDirStat screen after scanning a disk

The main pane on the top is a typical tree view that is sorted by folder size, but the treemap displayed in the bottom pane is what makes WinDirStat (and SpaceSniffer, covered next) unique among typical disk analyzers.

The treemap uses rectangles to represent files and folders, proportional to their size. In general, large rectangles represent folders and smaller rectangles represent files. A legend in the upper-right part of the screen helps you determine the type of files represented in the treemap.

When you click a rectangle, WinDirStat takes you to the location on the disk, displaying the same file or folder in the tree view at the top of the screen (see Figure 2).

Figure 2 Selecting a file in WinDirStat

Right-clicking a file or folder in tree view opens a menu from which you can open a file or folder, delete it, copy the path, or get property information, among other actions. The Clean Up item on the menu bar provides the same set of commands.

Another handy feature of the utility is the Options feature. Select Options > Show Free Space to see the proportion of free disk space at a glance. You can also use Options to show or hide file types, the treemap, the toolbar, and the status bar. Choose Unknown to see allocations for shadow copies and other system-controlled files, which can sometimes consume untoward amounts of disk space.

The Report feature lets you send an email to the computer owner (which might be you!) that lists the folders and files that should be considered for deletion in the near future.


SpaceSniffer shares several features with WinDirStat, such as the ability to select disks when the utility first starts, fast disk scanning, a treemap view, and the ability to open and delete files. However, it has some notable differences.

SpaceSniffer doesn't require any installation—just unzip the download file to a folder and run SpaceSniffer.exe. The utility also shows the treemap being built during the scan, which is surprisingly fascinating, and then opens to a full treemap view.

Figure 2 SpaceSniffer screen after scanning a disk

When you hover your mouse pointer over a rectangle, the program displays the folder or file name and its size in a pop-up window. Clicking a rectangle also displays the creation, last modified, and last accessed dates in the window. Double-clicking a rectangle zooms in, giving you a more granular view of the file or folder within the treemap. This is useful for clicking into folders that contain subfolders, so you can see what's inside of each folder.

Using the Filter toolbar, SpaceSniffer lets you search for files by file extension, size, approximate age (< 6 months, for example), attribute (archive, hidden, etc.), and name (with or without wildcards). You can combine multiple filters and tag files and folders to return to them later or to exclude them from a filter.

Once you identify files or folders you want to delete, just right-click and select Delete from the pop-up menu. You can also use the menu to open items; and a Send To item lets you create a ZIP file, create shortcuts on the desktop, send the file via email and more—much like Windows Explorer and File Explorer.

Like WinDirStat, SpaceSniffer lets you export a report to a file, enabling you to examine a list of files and folders to determine candidates for deletion.

Regular Inspection and Cleanup Help Manage Disk Consumption

We have gotten into the habit of running WinDirStat at least once a month, just to see what the composition of the files on our system disks looks like. Every now and then, we'll spot something big and unexpected or unwanted. When that happens, it may be necessary to run system utilities (such as dipping into System Restore and electing to delete all but the most recent Restore Point, for example) to free up space, or perhaps to run the "Cleanup system files" option in Disk Cleanup to remove extra files hanging around after installing a Service Pack or major update.

But if you keep an eye on how much space is being consumed and what's consuming it, you'll be able to get rid of the items that you don't need or want, and keep the amount of free space available as high as possible.

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