hard drive history

revolutions: 3600 > 4500 > 7200 rpm

Western Digital Caviar AC2850

Photo: Red Hill.

Western Digital Caviar AC2850

Our second choice 850MB drive, and no shame in that — these were one of the great drives: firmly in the tradition of the famous Western Digitals of 80MB and 210MB days. The Caviar 850 was an excellent substitute for the 850MB Decathlons when the Seagate drives were out of stock, particularly during the awkward two-month gap between the end of the 5850A and the first of the new model ST-5851A.

The Western Digital 850 was not only quick, it proved to be very reliable and many examples remained in service for years to come. Our own main showroom demo computer used an AC2850 and still ran plenty fast enough right up until early 1998; we traded AC2850s in eagerly and resold them happily until early in the new century.

As with many Western Digital units, the AC2850 was faster in real life than the not-especially-impressive raw specs suggested, perhaps because of a better than average ability to perform fast short seeks.

Data rate42.1 Mbit/secSpin rate4500 RPM
Seek time10msBuffer64k
Platter capacity427MBEncodingRLL
Form3½" 1/3 heightInterfaceIDE mode 3
AC-2850853.6MB4 thin film heads***