Fault-Tolerant Index Detection Pattern for Hard Disk Files
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
The pattern is a redundant pattern (1-2-3-4-5) of magnetic transitions imbedded on the dedicated servo surface of a hard magnetic disk to generate a fault-tolerant index pulse. The pattern (1-2-3-4-5) of magnetic transitions is a separate and distinct index pattern which is written once per revolution on the dedicated servo surface of the hard disk. The pattern is written in the fill area (D) of the figure immediately before the index servo identification pattern, which is the pattern (A) just preceding "Index Servo ID" in the figure indicating the index signal. The index pattern consists of the five consecutive (1-2-3-4-5) patterns which are identical. The index signal is generated at the servo identification "Index Servo ID", following the detected index pattern consisting of the five identical patterns (1-2-3-4-5).