US 6,583,944 B1 · Method and system for compensation for spin speed variation in a magnetic disk storage device

Abstract

A method, and a system for implementing such method, for use in a magnetic disk storage system for compensating for variation in spin speed of a data storage media from a nominal or design spin speed. The method includes providing the nominal spin speed for the data storage media in the particular magnetic disk storage system and then measuring the actual spin speed of the data storage media. In one preferred embodiment, the spin speed measurement is completed by measuring the time from one servo position field to the next sequential servo position field in a track on the data storage media. Next, the present spin speed variation is determined by comparing the measured spin speed with the nominal spin speed. A correction factor is calculated based on the spin speed error and applied to at least one data transfer parameter, such as channel reference frequency or read/write gate assertion timing, prior to a subsequent data transfer process (i.e., a read or a write operation). The spin speed compensation method may further include verifying that the measured spin speed is within a range of acceptable spin speeds. The range of acceptable spin speeds is determined based on maximum spin speed change rates of the magnetic disk storage system and the most recent measured spin speed. If the measured spin speed is outside this range, the data transfer operation, i.e., a write operation, is stopped to prevent damaging data previously stored on the data storage media.

Claims14

Dependent claims

A method for compensating for variation in spin speed from a nominal spin speed in a magnetic disk storage system including a data storage media rotatable at a spin speed, the method comprising:

providing the nominal spin speed of the data storage media in the magnetic disk storage system;
measuring the spin speed of the data storage media;
determining a spin speed error based on the provided nominal spin speed and the measured spin speed;
and
prior to a data transfer process in the magnetic disk storage system, applying a correction factor based on the spin speed error to at least one data transfer parameter used to control the data transfer process, wherein the at least one data transfer parameter is channel reference frequency.

2 more elements

A magnetic disk storage system for adjusting data transfer parameters to correct for spin speed variation of data storage media rotated within the magnetic disk storage system, the data storage media being separated into tracks having data sectors and servo position fields, comprising:

a read head positioned adjacent the data storage media for detecting when the read head is adjacent one of the servo position fields and, in response, transmitting a servo timing signal;
a controller communicatively linked to the read head for receiving a first and a second of the servo timing signals corresponding to a first and a second of the servo position fields;
and
a memory device for storing data and linked to the controller, the memory device having in storage a nominal spin speed value for the magnetic disk storage system;
wherein the controller is configured for measuring a spin speed of the data storage media using the first and the second servo timing signal, for determining a spin speed error by comparing the nominal spin speed value to the measured spin speed, and for adjusting at least one of the data transfer parameters to correct for the spin speed error;
wherein the memory device further includes a maximum spin speed rate change value for the magnetic disk storage system and wherein the controller is adapted for verifying the measured spin speed is within an acceptable spin speed range that is established by the controller by applying the maximum spin speed rate change value to the measured spin speed;
and
wherein the controller includes means for determining whether a requested data transfer operation is a write operation and wherein the controller is operable to halt the write operation when the measured speed spin is outside the acceptable spin speed range.

5 more elements

Dependencies are inferred from the claim text.

Method and system for compensation for spin speed variation in a magnetic disk storage device

Life of this patent

Method and system for compensation for spin speed variation in a magnetic disk storage device

Life of this patent

Abstract

Claims14