This will vary with disk models:
Take the number of sectors, divide by the number of (cylinders *
heads), this is the number of sectors that flies under one head in one
revolution of the disk.
Factor in the spindle-speed of the disk, and you get the number of
sectors/second that pass under one head.
Since only 1 head can be read or written at a time, this is the maximum
long-haul data transfer rate of the hard drive.
Sigh. Would that it were that simple. The number of sectors per cylinder is not constant across the platter. Modern disks have a (nearly) constant size sector so you'll find that the outer cylinders transfer faster than the inner cylinders. If you can write a whole cylinder (that is, across several platters) you'll get better transfer rates that you will if you write on adjacent cylinders. In other words, a disk with a lot of platters will tend to be faster than a disk with a single platter.
Current disk technology is somewhere around 45-50Mb/s (my shiny new disk is somewhere in this range). That's sustained data rate. This is rather faster that ATA33 (17Mb/s) and indeed faster than ATA66 (33Mb/s). Luckily I've got an ATA133 bus, but ATA100 would be fine (which is what this disk actually is).
jch
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