The main competitor of the µPD765 FDC chip on the market was the WD179x FDC chip family. Its main differences are:
* the 765 has 5 status registers, while the 179x only has one.
* the 765 has 3 scan commands, while the 179x has none.
* the 765 has 5 status registers, while the 179x only has one.
* the 765 has multi-byte "command phase" and "result phase", while commands are issued to the 179x by writing a single byte to the Command Register, after having set parameters in its dedicated registers. After the command completes, the Status Register contains all the status information in a single byte.
* the 765 has drive select pins to directly select one of four floppy drives, while the 179x has none. Instead, external logic must be used to handle multiple drives.
* the 765 only does standard track formats (preamble, marks and data fields), while the 179x will write anything you tell it in the write track (formatting a track) mode.