The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 08, 2002
Filed:
Sep. 08, 1999
International Business Machines Corporation, Armonk, NY (US);
Abstract
A system for preventing off track data write operations in data storage devices such as hard disk drives. In a preferred embodiment, the amplitude of a head output signal is monitored. The output signal amplitude value is determined by measuring the voltage of a capacitor used in a Variable Gain Amplifier (VGA) in an Automatic Gain Control (AGC) circuit of a hard disk drive channel unit. The measured head output signal amplitude is compared with a previously determined minimum normal head output signal amplitude reference value to determine whether the head output signal amplitude is within a normal operating range. If the measured value is less than the reference value then the head is in an off track position, and the data write operation is inhibited. Radial position dependent amplitude reference values can also be used.