Wednesday, August 15, 2007

Get More Hard-Disk Space by Using NTFS Compression

The quickest and easiest way to give your system more room is to use XP's built-in compression scheme for NTFS disks. Here's how to use itand how to convert your existing disk to NTFS if it doesn't already use it.

If you need more hard-disk space, don't buy another hard disk right away. First, consider using NTFS (NT File System) compression, which can give significantly more hard-disk space by compressing all the files on your PC. NTFS's on-the-fly compression capabilities can shrink the size of individual files and folders, or entire drives. When you use it, the files or folders will be compressed when they're on your hard disk to save space, but they will be decompressed automatically when you use them, and then compressed again when stored on your hard disk. This means that, unlike with a compression program such as WinZip (, you don't have to deal with decompressing as well as compressing files. You can also easily turn compression on and off.

Note that NTFS compression isn't available with a FAT32 filesystem, so if you have a FAT32 system you'll first have to convert to NTFS, as explained later in this hack. If you're not sure which filesystem your volume uses, right-click your volume in Explorer, choose Properties General, and look for the information next to File System.

How much disk space can you save by using NTFS compression? That depends largely on the kinds of files you have on your system. Bit-mapped graphics files are very compressible, so you'll save quite a bit of hard-disk space if you have many of them. Document files, such as Word files, are also reasonably compressible, while certain kinds of files, such as PDF (Adobe Acrobat) files, are barely compressible at all.

If you use NTFS compression on a file, the file can't be encrypted using XP's encrypting capabilities, so be careful not to compress any files that you want to encrypt.

In tests on my own PC, I found that bit-mapped .tif graphics files were compressed by more than 80 percenta folder full of them shrunk from 295MB to 57MB. Word files shrunk by 66 percenta folder full of them shrunk from 131KB to 44KB. PDF files, by way of contrast, hardly compressed at all: a group of them shrunk by just more than 6 percent, from 5.59MB to 5.27MB.

When you use compression, you might notice a slight drop in system performance. There might be a slight lag when opening or closing files, depending on the speed of your system, because the files have to be decompressed for you to open them and compressed when you save them. With newer systems, though, you probably won't notice a lag. On my now-aging 1.8GHz desktop, for example, I don't see a difference between working with files that have been compressed and working with files that haven't been compressed.

You can use NTFS compression on individual files, folders, and entire disks. To use NTFS compression on a file or folder, right-click the file or folder in Windows Explorer and choose Properties General Advanced. You'll see the screen shown in Figure 3-20.

Figure 3-20. Enabling compression on files and folders to save hard-disk space

Check the box next to "Compress contents to save disk space," click OK, and click OK again when the Properties dialog box appears.

If you want to compress an entire drive, right-click it in Windows Explorer and choose Properties General "Compress drive to save disk space." You'll be asked for confirmation, and then every folder and file on the drive will be compressed, one after another. Depending on the size of the drive, the procedure can take several hours. You can continue to use XP while the compression takes place. During that time, however, you might be prompted to close a file you're working on so that XP can compress it.

By default, XP visually differentiates between compressed files and decompressed files; compressed files are shown in blue. If for some reason your compressed files aren't blue, and you want them to be, from Windows Explorer choose Tools Folder Options View, scroll down, and select the checkbox next to "Show encrypted or compressed NTFS files in color."

Don't compress system files or .log files (files that contain logging information). If you do, your system can take a severe performance hit because these files are in frequent background use and compressing and decompressing them constantly takes up CPU power. If these files are in folders that are compressed, you can decompress just those individual files by unchecking the "Compress contents to save disk space" box next to them. You can also decompress the folder in which they are located in the same way.

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