Digibarn Collection ➔ Apple Duo Disk

In 1984, shortly after the introduction of the Apple IIe the previous year, Apple offered a combination of two, two third-height, 140-kilobyte Disk II drive mechanisms side-by-side in a single plastic case, called the DuoDisk (A9M0108), which can not be daisy-chained. The unit was designed to be stacked on top of the computer, and beneath the monitor. Each unit requires its own disk controller card (as each card can still control only two drives) and the number of units is thus limited to the number of available slots; in practice, few uses of the Apple II computer can make good use of more than two 5+1⁄4-inch drives, so this limitation matters little. Originally released with a DB-25 connector to match that of the Apple III Plus, it was the first to adopt Apple's standard DB-19 floppy drive connector.