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Method for Defining Start Point for Servo Writing

IP.com Disclosure Number: IPCOM000035879D
Original Publication Date: 1989-Aug-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Arai, A: AUTHOR [+4]

Abstract

Disclosed is a method for defining a starting point for writing servo on a hard disk drive (HDD). Servo writing on the HDD is to be done from an outer crash stop (abbreviated as O.C.S.) to an inner crash stop (I.C.S.). To find the point where the actuator touches the O.C.S., a read-back signal from the medium is used as described below:

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Method for Defining Start Point for Servo Writing

Disclosed is a method for defining a starting point for writing servo on a hard disk drive (HDD). Servo writing on the HDD is to be done from an outer crash stop (abbreviated as O.C.S.) to an inner crash stop (I.C.S.). To find the point where the actuator touches the O.C.S., a read-back signal from the medium is used as described below:

(1) Write a pattern where a servo writer's push-rod does not touch the actuator.

(2) Check if the read-back signal exists for confirmation.

(3) Move the writer's push-rod by half track pitch.

(4) If the read-back signal does not exist, the point where the push-rod touches the actuator is defined within the precision of half track pitch. If the read- back signal exists, repeat the steps from (3). (Refer to Fig. 1 for physical geometry.)

The preciseness for finding the starting point depends on a step move of the writer's push-rod of the process (3). This can be shorter or longer depending on the tolerance for finding the point.

It is necessary to find the servo-writing start point for the following reasons:

(1) For a sector servo system, where cylinder identifications (IDs) are to be written on a disk, it is necessary to write servo data from ID = 0.

(2) Since the O.C.S. is usually defined precisely by mechanical geometry aiming at the precise use of the magnetic medium, the point where the actuator touches O.C.S. is needed to be defined.

The advantage of this approach may be stated...