Browse Prior Art Database

Spindle Rotation Optimization for Disk Write/Read Operation

IP.com Disclosure Number: IPCOM000117824D
Original Publication Date: 1996-Jun-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 4 page(s) / 79K

Publishing Venue

IBM

Related People

Kakihara, T: AUTHOR [+3]

Abstract

Disclosed is a new disk write algorithm that uses an adaptive Spindle Motor Round Per Minutes (RPMs) optimization scheme to reduce the average access time for drive write operation. The spindle RPM for write commands from the host computing system is optimized by the microcode on hard disk drive electronics, based on factors such as host system data transfer rate, host command interval and access pattern; i.e., sequential or random.

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Spindle Rotation Optimization for Disk Write/Read Operation

      Disclosed is a new disk write algorithm that uses an adaptive
Spindle Motor Round Per Minutes (RPMs) optimization scheme to reduce
the average access time for drive write operation.  The spindle RPM
for write commands from the host computing system is optimized by the
microcode on hard disk drive electronics, based on factors such as
host system data transfer rate, host command interval and access
pattern; i.e., sequential or random.

      If the host transfer rate is slower than disk data transfer
rate and access pattern is sequential write, then the spindle RPM
will be slowed down by the microcode not to miss a disk revolution.
If the access pattern is random, then the spindle RPM will be made
faster to reduce its rotational latency.

      Prior technology simply rotates the spindle motor at a fixed
RPM, so the drive misses disk revolutions very frequently while
writing data to the disk media, if the host transfer rate is slower
than the drive media transfer rate.  This missing revolution degrades
the average  access time and effective data transfer rate to a great
degree.

      Fig. 1 shows the disk write time when a missed revolution
occurs.  One disk revolution takes about 11 ms at 5400 RPM.

      Recent evolving hard disk drive technologies are improving
media transfer rates drastically, while the host transfer rate has
not been improved very much.  Therefore, this degraded...