SmartDrive was a disk caching program that shipped with MS-DOS versions 4.01 through 6.22 and Windows 3.x.[1] It improved disk transfer rates by storing frequently accessed data in the main memory. Early versions of SmartDrive were loaded through a CONFIG.SYS device driver named SMARTDRV.SYS. Later versions were loaded through an executable file named SMARTDRV.EXE, usually automatically at boot time by including the SMARTDRV.EXE command in AUTOEXEC.BAT (or install=SMARTDRV.EXE into CONFIG.SYS), though it could still be loaded as a driver if double-buffering was required.
The Windows 2000 and XP setup programs suggest that SmartDrive be used to decrease installation time when installing from MS-DOS.[2]