Saturday, August 14, 2010

Floppy disk drive

The term was first used by Apple Computer in 1988 to refer to their 1.44 MB 3.5 inch floppy drive. This replaced the older 800 KB floppy drive that had been standard in the Macintosh up to then, but remained compatible in that it could continue to read and write both 800K (double-sided) and 400K (single-sided) floppy disks, as well as the then-new high-density floppies. This drive was also capable of reading and writing MS-DOS formatted disks and FAT file formats, using PC Exchange or other software, unlike the 400K and 800K drives. This was made possible as the SuperDrive now utilitized the same MFM (Modified Frequency Modulation) encoding scheme used by the IBM PC, yet still retained backward compatibility with Apple's variable-speed zoned CAV scheme and Group Code Recording encoding format, so it could continue to read Macintosh MFS, HFS and Apple II ProDOS formats on 400/800K disks.

Introduced in 1988 under the Trademark name FDHD (Floppy Disk High Density), the subsequently renamed SuperDrive was known primarily as an internalized floppy drive that was a built in part of the Macintosh computer; however, an external version of the drive was manufactured that came in a Snow White-styled plastic case. While the external drive worked on both Apple's product lines, it was mainly intended for use on the Apple II series, for which Apple introduced in 1991 a slot-based interface called the Apple II 3.5 Disk Controller Card for Apple IIe and IIGS computers so they too could use 1.4 MB storage and read/write MS-DOS. The controller card as well as the external Superdrive were discontinued in June 1994. The SuperDrive cannot be used with the original Macintosh 128K through Macintosh Plus, nor with the stock Macintosh II or Macintosh SE (for which an upgrade kit was available), though it will act like an 800K drive if connected.

The first Macintosh model to include a SuperDrive floppy drive was the Macintosh IIx. Every Macintosh and PowerBook introduced from 1988-1997 (with the exception of the PowerBook 100, PowerBook Duo series, and PowerBook 2400c, which offered a proprietary external floppy drive as an option), had a built-in SuperDrive floppy drive (advertised as a 1.44 MB floppy drive).[citation needed] The last model to include this feature was the Power Macintosh G3 series, which was manufactured until January 1999. The PowerBook G3 1998 model, (a.k.a. Wallstreet) had an optional floppy drive module. The PowerBook 190 series, PowerBook 5300 Series, PowerBook 3400c, and original PowerBook G3 shared the same interchangeable floppy drive module as a standard feature. The PowerBook 1400 series also had a floppy drive module, but was incompatible with the other PowerBooks. The end of the SuperDrive coincides with the demise of Old World ROM Macs; with the advent of the New World ROM machines, Apple stopped offering internal floppy drives on all models. The SuperDrive is not supported in Mac OS X even on the few Old World ROM machines that can officially run OS X.

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