Browse Prior Art Database

Track Servo System

IP.com Disclosure Number: IPCOM000080416D
Original Publication Date: 1973-Dec-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 3 page(s) / 52K

Publishing Venue

IBM

Related People

Shew, LF: AUTHOR

Abstract

This servo system provides means for a servo track to be closely adjacent to the data track, or for using the data as servo information. The method would reduce the data head position errors caused by temperature gradient and certain mechanical component build-ups. Consequently, a more accurate track-following servo system can be achieved.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 3

Track Servo System

This servo system provides means for a servo track to be closely adjacent to the data track, or for using the data as servo information. The method would reduce the data head position errors caused by temperature gradient and certain mechanical component build-ups. Consequently, a more accurate track- following servo system can be achieved.

One type of servo system currently used in random-access disk files generally employs a separate surface or a separate band on a given surface, to provide the necessary track servo information. The disadvantage of this scheme is that the servo head and data head are placed far apart, resulting in a large position error due to their large temperature difference. Another disadvantage is the reduction in the utilization of the recording surfaces for data storage, since a larger portion of the area has to be allotted for servo information.

Another type is the sectorized servo system in which many sectors of servo information are prerecorded on the data track, and the separation of servo information and data is by time division multiplexing. This method, however, requires too many sectors of servo information. There is also a third type of servo system which uses the data for servo information. But it is impractical because electronics have drift so that it would shift off the track center and "walk away" after several times of rewriting.

The method described here is to insert one or a few short sectors of sample servo information (200-300 bytes) on each track to assure that the track center would not be shifted, and to use its own data or data on an adjacent track for servo information, as shown in Figs. 1 and 2, respectively. With this method, only several hundred bytes of sample servo information on each track are required. In high-linear density recording, this amount of servo information would constitute less than one...