Browse Prior Art Database

High-Speed/Low-Power Selectable Optical File

IP.com Disclosure Number: IPCOM000103174D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 43K

Publishing Venue

IBM

Related People

Luecke, F: AUTHOR

Abstract

Disclosed is the concept of having two or more speeds ranging from "high performance" (fast) to "maximum economy" (slow) available for the operation of an optical or magnetic DASD disk file. In any application it is good to minimize the power consumed and the heat produced by the file, and in battery-powered systems, such as laptop computers, the operating time between charges can be increased by minimizing the power consumed by the file. On the other hand, it is occasionally desirable for the file to have high performance.

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High-Speed/Low-Power Selectable Optical File

      Disclosed is the concept of having two or more speeds ranging
from "high performance" (fast) to "maximum economy" (slow) available
for the operation of an optical or magnetic DASD disk file.  In any
application it is good to minimize the power consumed and the heat
produced by the file, and in battery-powered systems, such as laptop
computers, the operating time between charges can be increased by
minimizing the power consumed by the file.  On the other hand, it is
occasionally desirable for the file to have high performance.

      A large fraction of the power consumed by a file is used in
spinning the disk and in operating the actuator to seek and follow
tracks.  The energy required by the spindle motor to spin the disk
varies approximately with the 2.8th power of rotational speed.  The
power used by the actuator for focus and tracking varies with the 4th
power of disk RPM, and power varies inversely with the 4th power of
access time. This being so, the required energy can be lowered
appreciably by operating both the spindle motor and actuator at less
than maximum speed for all but the most urgent, file-intensive parts
of an application.

      Implementation of this concept requires that the channel and
other electronics be capable of operating at more than one frequency,
a capability already implemented in some files due to the use of
banding.  Less, but still significant, power savings would result
fr...