Commodore CBM 4040 Dual Drive Floppy Disk

Commodore CBM 4040 Dual Drive Floppy Disk

I must thank Davide M. for the donation.


The Commodore 4040 is the replacement for the previous models 2040 (USA) and 3040 (Europe). It’s a dual drive 5¼” floppy disk subsystem for Commodore International computers. It uses a wide case form, and uses the IEEE-488 interface common to Commodore PET/CBM computers.

These drive models use a similar single density, single side floppy data storage format to that used by the Commodore 1541 drive, but with a slightly different data marker indicating which model originally formatted the disk. The low-level disk format was similar enough to allow reading between models, but different enough that one series of drive models could not reliably write to disks formatted with one of the other model series.

Download: CBM 2040-3040-4040-8050 Disk Drive Manual (1235)

Testing the Floppy Drive with the ZoomFloppy interface:

source: wikipedia

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