In computing, Diskcomp is a command used on MS-DOS, PC DOS, OS/2 and Microsoft Windows for comparing the complete contents of a floppy drive to another one.
Media limitation
Diskcomp does not work with hard drives, CDs, network drives, ZIP drives, or USB drives, etc. It also does not allow diskcomp from 3.5 inch drive to 5.25 inch drives, and vice versa. The source and target drive must be the same size.
References
Diskcomp Wikipedia(Text) CC BY-SA