Microsoft MS-DOS version 6.x introduced the DriveSpace file system, which increases the storage capacity of disk drives by compressing data written to the drive. DriveSpace includes a programming interface that lets disk utility programs examine and manage disk drives containing compressed data. The DriveSpace programming interface is described in the MS-DOS Programmer's Reference for version 6.x. This section describes additional IOCTL functions that have been added to the DriveSpace programming interface for Windows 95.