I agree that it's likely to be a floppy drive controller.
The 74LS38 devices use open-collector logic, as do PC floppy drives. There are what appear to be pullup resistors adjacent to the 34 way connector and the 34 way cable has a connector for a second device half way along it in the same fashion that floppy drive cables are set up. However, this last observation may simply mean that the cable is off a PC floppy drive, while the card was intended for something else.
The mystery is; if it is a floppy controller, then where is the PLL and all the associated "analog" stuff? The Apple II floppy controller cards were unique in that they used some very clever Woz logic to do away with all the traditional complexity of a disk controller. I've never seen anyone else emulate this.
The 74LS38 devices use open-collector logic, as do PC floppy drives. There are what appear to be pullup resistors adjacent to the 34 way connector and the 34 way cable has a connector for a second device half way along it in the same fashion that floppy drive cables are set up. However, this last observation may simply mean that the cable is off a PC floppy drive, while the card was intended for something else.
The mystery is; if it is a floppy controller, then where is the PLL and all the associated "analog" stuff? The Apple II floppy controller cards were unique in that they used some very clever Woz logic to do away with all the traditional complexity of a disk controller. I've never seen anyone else emulate this.