The Commodore 1581 has a external power supply, one diskette station with two read / write heads and a motherboard. On the motherboard you will find RAM and ROM memory, a MOS 8520 CIA and a MOS 6502 processor. The Commodore 1581 disk drive is a smart device, reading and writing works independent of the connected computer.
The 1581 disk drive can only read and write data in the MFM format.