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Abstracts - 1997 ANNUAL TECHNICAL CONFERENCE
Observing the Effects of Multi-Zone Disks
Rodney Van Meter
Information Sciences Institute,
University of Southern California
Abstract
Current generations of hard disk drives use a technique known as
zoned constant angular velocity (ZCAV), taking advantage of the
geometry to increase total disk capacity by varying the number of disk
sectors per track with the distance from the spindle. A side effect of
this is that the transfer rate also varies with sector address. We
analytically estimated and measured this effect on file system
performance on a BSD Fast File System, showing a drop of roughly 25%
in peak transfer rate depending on head position. We also show that,
while ZCAV effects cannot be ignored, a simple linear model adequately
estimates the performance from the few parameters normally available
in disk drive spec sheets.
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Technical Program