Browse Prior Art Database

Constant Density Signals on Record Storage Disks

IP.com Disclosure Number: IPCOM000086839D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Cope, JR: AUTHOR

Abstract

At different radial positions of a record storage disk, signal densities can be different with different levels of signal outputs. In accordance with the present technique, the signal amplitude output and the lineal bit spacing are both constant with radius.

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Constant Density Signals on Record Storage Disks

At different radial positions of a record storage disk, signal densities can be different with different levels of signal outputs. In accordance with the present technique, the signal amplitude output and the lineal bit spacing are both constant with radius.

The above-stated results are achieved by making head-gap positioning movements along a chordal (as opposed to a radial) line of the record disk. At a radial inwardmost position A, the width of the scanned track is a maximum while at a radial outwardmost position E the track width is minimal. This width variation plus the radially determined head-to-medium variations result in a constant amplitude signal output and a given constant lineal bit spacing. The intermediate tracks B through D have corresponding track widths and speeds to yield the constant amplitude signal output at a given bit density. The reduced track width results in reduced amplitude at a given track-to-head speed. Because of increasing speed at increasing radii, the output amplitude is constant.

The head positioning movements are shown as being along a true tangent to the disk concentric tracks. The gaps may be skewed and the head motions may be correspondingly skewed with respect to such true tangents. That is, the head motions may be, as shown by dotted line F, which is disposed at an angle phi with respect to two tangent lines for the illustrated head-gap positions. The orientation of the gap...