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:
Jul. 13, 1999
Filed:
Jul. 22, 1996
Masashi Kisaka, Yokohama, JP;
Nobuyuki Kitazaki, Fujisawa, JP;
Takashi Nakamura, Fujisawa, JP;
Yuji Yokoe, Yokohama, JP;
Isao Yoneda, Yokohama, JP;
International Business Machines Corporation, Armonk, NY (US);
Abstract
The present invention determines whether a filter is used for reading and writing on a disk to correct repeatable runout. The invention estimates the magnitude of repeatable runout for each disk by measuring the maximum absolute value of a state variable of a filter when the disk is turned on or when the disk returns from a sleep mode, and compares the measured value to a predetermined criterion such as the track width. If the magnitude of the repeatable runout is less than or equal to the predetermined criterion, the filter is not used. If the magnitude of the repeatable runout exceeds the predetermined criterion, the invention reads and writes data using the filter.