The 4MMIBM.SYS supports 2 models of the IBM 4mm DAT tape drive:

IBM 2.0Gb 4mm Tape Drive Option (part number 55F9428)
        firmware identifier IBM HP35480A !C6

IBM 2.0Gb 4mm DAT 3440 001
        firmware identifier HP IBM35480A !C5


To install this driver, please copy all files in this directory to the root
directory of a floppy disk in drive A:, and label that disk 4MMIBM.

Start the SETUP application in Windows NT.

Select ADD/REMOVE TAPE DEVICES under the OPTIONS menu.

Click on the ADD button.

Select "OTHER (requires a disk from hardware manufacturer)"

Insert the disk labeled 4MMIBM into drive A: and click on OK.

Click on OK to approve the selection of IBM 4mm DAT.

Click on INSTALL to install the driver.

Click on OK to copy the files from drive A:.

Click on CLOSE to close the window.

Select EXIT from the OPTIONS menu to exit SETUP.

You will need to restart your computer for these changes to take effect.
Please choose SHUTDOWN from the FILE menu in Program Manager to do this.