This page contains every external drive in the collection compatible only with Apple II computers. This page will be updated as we obtain more drives. Some drives in the collection are compatible with both Macintosh and Apple II computers. These drives can be found on the External Macintosh Drives page. Connecting a drive to a card or built-in port that is incompatible could result in damage to the computer and the drive. Consult Apple.com support pages to collaborate information posted here or on any other third-party or hobbyist site before you use your Apple drive.
The Disk II is Apple's first disk drive. The Disk II drives were revolutionary for their time. Steve Wozniak substantially designed the circuitry for the Disk II in the late 1970s when the Apple II was Apple's only product. He figured out a way to build the drive for a fraction of the cost of comparable 5.25-inch magnetic drives at the time. Even at a cost of about $600 each (including the controller card), these drives were an incredible bargain. They were fast, quiet, durable, and relatively inexpensive. Woz accomplished with a small controller card the same thing it previously took a card many times the size with many more chips. The Disk II uses the Disk II Interface Card to connect to an Apple II computer. Disk II drives are attached directly to the card by a ribbon cable, unlike later generation Apple 5.25-inch drives that use a 19-pin connector. The Disk II Interface Card supports up to two Disk II drives at a time. The Disk II has a sturdy metal case that is painted beige with a black face. It can support a monitor but it is unadvisable to place a monitor on top of two Disk II drives because a heavy monitor can cause the case to bend down and affect the drive mechanism.
The UniDisk 5.25 reaplaced the Disk II. The drive mechanism is the same as the drive for the DuoDisk, the Apple IIc internal drive, and the Disk IIc. The UniDisk 5.25 uses a 19-pin connector and works with the Apple 5.25 Disk Drive Card. For each controller card connected to a UniDisk, a second UniDisk drive can be daisy-chained or connected to the back of the first. Unlike the Disk II, the UniDisk 5.25 is constructed of molded plastic, which actually makes its construction sturdier than its predecessor. The first version and the one pictured on this page was beige in color. Apple later changed the color to platinum (blue-gray). A9M0104 was bundled with an Apple 5.25 Disk Drive Card. A9M0105 shipped without the card.
The DuoDisk is essentially two Unidisk 5.25 drives in a single enclosure. It has a beige case and does not have a pass through port because the Apple 5.25 Disk Drive Card only supports two disk drives. The DuoDisk uses a special cable that is completely detachable from the drive, unlike the single UniDisk 5.25 drive, which has a connector that is not detachable from the drive case. There is a compatibility problem with the DuoDisk and ROM 3 Apple IIgs main logic board. The DuoDisk does not work with the SmartPort because there is some code in the ROM that does not handle the interface to a DuoDisk properly. One workaround is to use the DuoDisk on an interface card like a DuoDisk Interface Card. On ROM 01 IIgs computers, you can connect the DuoDisk directly to the SmartPort or to a drive attached to the SmartPort. If you plan to attach the DuoDisk to the SmartPort on the back of a ROM 3 IIgs, then you need to make sure the DuoDisk's analog board has a particular modification. If it lacks this modification, you can do it yourself. This modification is not necessary if the DuoDisk is the only drive in the chain attached to the SmartPort. The modification can be found at http://support.apple.com/kb/TA36357. The original ROM version of the Apple IIc only supported a single 5.25-inch external drive. Later versions supported daisy chaining up to two external 5.25-inch drives. Use of the DuoDisk with later versions of the IIc might work, but we have not tested it. Disk Medium:
The Apple 5.25 Drive replaced the UniDisk 5.25. It has a platinum case. Generally, the UniDisk 5.25 and Apple 5.25 drives are interchangeable. However the UniDisk 5.25 is not compatible with the Apple IIe Card because it uses a voltage (-12 volts) that the Macintosh LC does not support. The Apple 5.25 Drive uses the same 19-pin connector as the UniDisk 5.25.
Apple released this very stylish drive in 1984 along with the Apple IIc. Its off-white case matches the industrial design of the Apple IIc. This drive is the first Apple II drive to use a 19-pin connector. It does not have a pass through connector because the original version of the Apple IIc does not support more than one external 5.25-inch disk drive. The drive is otherwise mechanically the same as the UniDisk 5.25 and it will work with an Apple 5.25 Disk Drive Card.
The UniDisk 3.5 was designed to use exclusively with Apple II computers. The UniDisk 3.5 is not compatible with the original version of the Apple IIc (ROM version '255') but will work with later ROM version '0' and above. The UniDisk 3.5 has an off-white case and a pass through connector for daisy-chaining other drives. The Apple II, Apple II Plus, and Apple IIe require the Apple 3.5 Disk Drive Card (the "Liron" card). The UniDisk 3.5 is compatible with 800K double density floppy disks. The drive can also use 400K single density floppy disks but will only work with double density disks on the Apple IIc. The IIgs supports the UniDisk 3.5, but the drive is slower than later Apple external 3.5-inch drives.