Radially-Coherent Reading and Writing System and Method for a Magnetic Disk

Abstract

Radially-coherent data reading from, and data writing to, a magnetic disk use non-coherently written synchronization signals on the disk. In a form, the radially-coherent data reading and writing is performed using a magnetic head / disk tester which includes a spinstand for supporting a spinning magnetic disk, a magnetic head assembly, a write channel network for generating a write data signal for application to a write element of the magnetic head, a read channel for receiving a read-back signal from a read element of the magnetic head assembly, and a signal processing system that analyzes a read-back signal from a disk and provides synchronization signals for radially-coherent data reading and data writing.

Description

RELATED APPLICATION(S)[0001]This application claims the benefit of U.S. Provisional Application No. 62 / 001,842, entitled “Radially-Coherent Reading and Writing System and Method for a Magnetic Disk,” filed May 22, 2014. The entire teachings of the above application(s) are incorporated herein by reference.FIELD OF INVENTION[0002]The present technology relates generally to magnetic head / disk testers, and more particularly to systems and methods for radially-coherent reading from, and writing, to a magnetic disk.BACKGROUNDRadially-Coherent Writing[0003]It is common in the art that data be written to a plurality of concentric (about a rotation axis RA of a magnetic disk) circular data tracks on a magnetic disk. The written data is “radially-coherent” in a range of radial positions along the respective data tracks if for each radial position in that range, the bits of the written data start from the same (or a “common”) radially-extending reference line on the magnetic disk, and all magn...

AI Technical Summary

Benefits of technology

Enables precise radially-coherent writing and reading on magnetic disks without pre-written servo information, reducing synchronization jitter and improving data alignment, thus enhancing the capabilities of head / disk testers for modern data densities.

Problems solved by technology

This severely limits the radially-coherent writing capabilities of conventional-type head / disk testers, such as that shown in FIG. 4, which employs the above described spindle optical encoder synchronization method.

The prior art head / disk testers are too imprecise for modern heads and data densities.

The drawbacks of such servo writer methods are:1. Usage of required expensive servo writing equipment; and2. Following pre-writing of the radially-coherent servo data on the disk, it is necessary to transfer the magnetic disk from the servo writer equipment to a head / disk tester.

A further drawback of above-described the two-step self-servo writing, is that the disk drive needs to be disassembled in order to remove the servo written disk from the disk drive in order to put it on a head / disk tester.

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