MS CD Extensions (MSCDEX) 1.25

MSCDEX is the real-mode MS-DOS file system redirector used in conjunction with your CD-ROM driver for accessing CD drives. The CD-ROM driver, which is provided by your CD-ROM drive manufacturer, provides the hardware and protocol specific software interface to your drive. MSCDEX interfaces with this driver to present the raw CD-ROM data as a file system accessible as a DOS drive letter.

In the early days of CD-ROM drives, there were many different hardware and protocol interfaces. These included SCSI, MKE, IDE/ATAPI, and more. MSCDEX provides the drive-independent portion needed to make use of CD drives under MS-DOS.