NTFS Compression Compared to Other Methods

Other compression utilities are available to compress files on computers running Windows NT. These utilities differ from NTFS compression in the following ways:

• They usually can be run only from the command line.

• Files cannot be opened when they are in a compressed state — the file must first be uncompressed by using the companion program to the one used to compress the file. When you close the file, it is saved in an uncompressed state, and you have to use a program to compress it.

The Windows NT Workstation Resource Kit includes a compress program and two expand utilities. The compress program can only be run from the command line. There are two versions of the expand program: one runs from the command line, and the other is a Windows NT–based program. For more information, see "File System Utilities" in Chapter 22, "Disk, File System, and Backup Utilities."

As described earlier, the DoubleSpace and DriveSpace compression features in MS-DOS cannot be used when running Windows NT.