External 1.2MB 8″ floppy disk drive


I have a weird obsession with ancient storage media, so I bought a 8″ floppy disk drive built in 1983 and a pack of disks. I wanted the ability to read and write these ridiculous floppies but I wasn’t interested in buying a huge IBM Displaywriter to go with it.

This project is a low-level controller for the IBM 6360 with a USB interface.

Data Bus Bit [0-7]Typical 8-bit data bus.
Address Bit [1-4, 8]Each disk has 77 tracks. Each track has 26 sectors of 128 bytes each. 5 address bits can locate 32 indices – perhaps these are registers in the onboard disk controller?
DMA [Request, Acknowledge, Request transmit, Request receive, Acknowledge transmit, Acknowledge receive]Perhaps there are 3 stages:
1. A DMA write (transmit) or read (receive) is requested by the host.
2. The DMA action is acknowledged by the disk controller.
3. A data block is contiguously sent from either the host or the drive.
4. The DMA request line is deasserted.
Interrupt [1, 4, 7]WTF
Diskette Select
Diskette Ready
I/O Read
I/O Write
Terminal Count
SelectSide select?


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