hard drive history

finding the formula: ide as we know it

Various early Western Digital Caviar drives

Photo: Red Hill.

Western Digital Caviar AC2200

The earlier of the two Western Digital 210MB drives. These were very common in the market: we hardly sold any new but would see many of them over the years following.

The AC2200 was fairly fast but (as with many WD drives from this period) prone to stiction problems — the heads sticking to the surface of the disc. This usually occurred when the machine had been switched off for a long time; the first few shopping days after Christmas and Easter always used to bring in two or three computers which wouldn't spin up because the heads had welded themselves to the discs.

There were two short-term cures: in some of the older MFM drives you could rotate the spindle by hand; with sealed units like the AC2200 it was more brutal: switch the drive on while shaking it hard! If the problem recurred, as it usually did, the drive needed replacement.

Until about 1998 all Western Digital drives, by the way, had the exact same master/slave jumper settings. This made them very easy to work with — whether it was 40MB or 40GB, you didn't have to scratch around for a manual, just set a single jumper to turn master into slave. Nearly all the CD-ROM and DVD drive makers adopted the simple WD jumper setup too, and continued to use it right up until the end of IDE drive production around 2010.

Illustration: I don't have an AC2200 to photograph, but it was very similar to the Western Digital drives from around the same era pictured here.

Data rate18.7 Mbit/secSpin rate3652 RPM
Seek time14msBuffer64k
Platter capacity106.3MBInterfaceIDE
Actuatorvoice coilForm3½" 1/3 height>
AC2200212.6MB4 thin-film heads*