hard drive history

size still matters: is there ever enough?

Western Digital Caviar AC22000

Photo: Red Hill.

Western Digital Caviar 1.28 Family

WD was the last major maker to use thin-film head technology across its entire desktop model range — IBM, Seagate, Quantum, Maxtor and Fujitsu all switched to MR heads before Western Digital — and these members of the Caviar 1.28 family were the last thin-film drives ever made. They were excellent performers nevertheless. This family of drives was also the last to spin at Western Digital's traditional 5200 RPM instead of the standard 5400.

(At this point the alert reader will recall that I described the Seagate Medalist 4500 as the last thin-film head drive. This is correct! The WD was released long after the Medalist 4500, but ceased production earlier, so both drives can claim to be the "last", depending on which way you look at it.)

The 2.5GB AC22500 was very popular here at Red Hill, and great value for money. The 2.0GB AC22000 is mainly included for the sake of interest as we only sold a few dozen of this excellent but short-lived drive. It was our original replacement for the wonderful old IBM Deskstar 2.1, and was itself soon replaced on WD Australia's shelves (for some unknown reason) by the marginally larger but older and slightly slower AC22100 . Notice how the three WD 2GB drives form a neat sequence of shrinking head-count, lower cost, and higher performance. The pattern reached its logical conclusion a little later still with the single platter AC12100, which was the last of the Western Digital 2GB drives.

As a rule of thumb, the appearance of single platter drives signaled the beginning of the end for a size category; in the 1990s only about half the manufacturers would usually bother to do a single platter model — it was a finely balanced equation: was it better to tool up for a short production-run, low-cost new single platter drive, or just to keep on making the old two-platter model for a while longer?

Data rate114 Mbit/secSpin rate5200 RPM
Seek time11msBuffer256k
Platter capacity1.28GBInterfacemode 4
Read channelPRMLHead technologythin film
AC120001.28GB2 heads
AC220002.0GB3 heads**
AC225002.56GB4 heads****
AC332003.25GB5 heads*
AC340004.0GB6 heads