hard drive history

smaller, faster: early 3.5 inch drives

Tandon (Western Digital) TM262

Photo: Red Hill.

Tandon TM262

Western Digital WD262

A very old drive and one of the first models to come in the then-new 3.5 inch size. The TM262 and TM362 were essentially identical: the only difference was that the 262 had a factory-fitted 5¼ inch mounting bracket.

The TM262 made an unusual, soft, sweet sound and was very slow (look at the seek time!) but it was usually pretty reliable and a good many examples survived in working order until they were no longer useful — something you could not say about quite a few of the less durable drives of this era.

Tandon was a little-known but quite successful drive manufacturer in the early days.

Western Digital did not make hard drives. WD manufactured hard drive controller cards for use with any brand of drive. WD had the foresight to see that integrating controller cards into the drives themselves was the way of the future, but was unable to find a drive manufacturer willing to work together on a joint venture. So in 1988 WD simply bought one, Tandon. This is why some of the last TM262s made had Western Digital badging.

Illustration: the genesis of Western Digital. Lower left, a Tandon TM362; upper left, Western Digital WD1003-WAH AT controller; right, WD262 (a Western Digital branded version of the same drive).

The 262 shows up an anomaly in our performance rating system: it was clearly quite a lot slower than the average MFM drive of the time but that doesn't show up in the figures. I suspect that the issue hinges on the internal data rate: all MFM drives are regarded as having had a 5 Mbit/sec data rate (as much a limitation of the controller as the drive) but some were much more capable than others of being tuned up by changing the interleave ratio. With a good drive and the right controller you could do a lot with MFM. The details of this are beyond the scope of this page, but I'll try to find time to add a page about it one of these days.

Data rate5 Mbit/secSpin rate3568 RPM
Seek time85msActuatorStepper
Platter capacity10.7MBInterfaceMFM
AT drive type2Form3.5" half-height
TM262 and TM36221.4MB4 thin-film heads1986?
WD262 and WD36221.4MB4 thin-film heads1988