Browse Prior Art Database

Enhanced Means for Rapid Reading And Writing of Cylinders in Small Or Thermally Active Multidisk File Memories

IP.com Disclosure Number: IPCOM000101811D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 78K

Publishing Venue

IBM

Related People

Siverling, MM: AUTHOR

Abstract

Described is a device for aligning heads to compensate for drift in a disk head arm assembly comprising multiple read/write heads.

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Enhanced Means for Rapid

Reading

And Writing of Cylinders in Small Or Thermally Active Multidisk File Memories

       Described is a device for aligning heads to compensate
for drift in a disk head arm assembly comprising multiple read/write
heads.

      A Direct Access Storage Device (DASD) typically comprises a
number of identical data storage disks attached to a single rotating
spindle.  Information is stored on concentric tracks on the surfaces
of the disks.  The set of all tracks a given radius from the disk
center constitutes a cylinder.  A head arm assembly contains one
read/write head for each disk surface containing data.  When data is
accessed, the head arm assembly positions the heads over a given
track of their respective disk surfaces, thus accessing all tracks of
a cylinder simultaneously. The development of DASD with greater data
density has lead to narrower tracks, and consequently lower
tolerances for misalignment of the different heads on the head arm
assembly.  As a result of these lower tolerances, differences in
thermal expansion and other factors can cause heads to drift out of
alignment.

      This invention counteracts drift by introducing an apparatus on
each arm of the head arm assembly that can cause a small controlled
movement of the head in the plane of the disk surface.  A wedge,
sector or other servo pattern can be used to periodically determine
the relative mismatch of the head positions to their track center
lines and fe...