What is it?

A drop-in replacement for Apple’s long-unavailable DISK II interface card that uses a modern SST29EE010 EEPROM instead of the obsolete 256-byte PROM. The board keeps the original 2-drive Shugart pinout and 13-sector/16-sector firmware, so any Apple II, II+ or //e can boot and write 140 kB disks exactly as it did in 1978—only now the firmware can be reflashed in seconds.

Why did you make it?

Original DISK II PROMs (2316B/6332) have been out of production for decades; NOS parts are expensive, unreliable and often already half-dead.
By moving the 2 kB image into a single 5 V EEPROM we restore the card to “new” status, eliminate UV-erase headaches and give owners an upgrade path: simply re-flash the EEPROM to add speed-matching, half-tracking, or even 800 kB 3.5″ support later.

What makes it special?

100 % hardware-compatible: same 20-pin IDC connectors, same boot ROM entry points, same timing—no software patch required.
Dual-drive ready: on-board termination and daisy-chain header let you run two original Disk II drives (or modern 5.25″ replacements) without extra cards.
Future-proof: the 128 kB EEPROM is 98 % free, so hobbyists can add diagnostic tools, disk-copy utilities or even a tiny OS in the unused space.