US 5,050,169 A · Method and apparatus for testing magnetic disks

Abstract

An apparatus for testing of multiple disks in a disk drive, and a method for testing utilizing the apparatus. Disks in a disk stack have associated read/write heads, and multiple read/write heads are controlled by read/write controllers. The controllers are controlled by chip select lines, and the read/write heads are selected via a head select bus. The disk stack is rotated by means of a motor or other rotation mechanism, and data is written onto tracks on surfaces of the disks by means of the read/write heads. A given head is selected by selecting its associated controller, and selecting the head code for that particular head. Multiple controllers may be selected at one time, with one head per controller engaged for the write function at a given time, such that several heads may be written at a time for speeding up the write proces in a disk testing procedure. In an alternative embodiment, several heads may be accessed per controller at one time. Test data is written onto each track on each surface of the disks by accessing all of the heads for each controller, and then the data is read out by accessing the read/write heads one at a time, and comparing the readout data with the written data for detecting faults on the surfaces of the disks. The method may be utilized with conventional head disk assemblies by disabling standard write unsafe lines, which normally prevent the enabling of more than one read/write controller at a time. The procedure is governed by a microprocessor, which controls each of the input, output and select lines.

Claims17

Dependent claims

A method for writing to a plurality of memory disks in a head disk assembly, the assembly including a plurality of read/write heads associated with surfaces of said disks, the assembly further including a plurality of read/write control chips, each chip being for controlling a number of the read/write heads and each chip including a chip select line, at least one head select bus, and data input lines and data output lines, said assembly being configured so that different data signals may not be supplied to said read/write heads simultaneously, the method including the steps of:

(1) selecting a plurality of the chips by selecting a plurality of the chip select lines simultaneously, for causing each of the selected chips to enable at least one head controlled thereby to write onto its associated surface;
(2) providing a first head select signal on each said head select bus for selecting a first said head for each said chip;
and
(3) providing write data over said data input lines for writing onto a track of a surface associated with each said first head, said write data being identical for each said first head.

1 more element

An apparatus for detecting flaws in computer disks, the disks being included in a head disk assembly, where the assembly includes a first read/write head associated with a first surface of each disk and a second read/write head associated with a second surface of each disk, the assembly further including a plurality of head control chips for controlling read and write operations of the heads, where a predetermined number of heads is controlled by each such chip, said assembly being configured so that different data signals may not be supplied to said heads simultaneously, the apparatus comprising:

means for simultaneously providing a write signal to all of the first heads for storing identical data on said first surfaces;
means for reading said data from said first surfaces via said first heads;
and
means for comparing said read data with said written data for detecting the presence of flaws on said first surfaces of said computer disks.

1 more element

Dependencies are inferred from the claim text.

Method and apparatus for testing magnetic disks

Life of this patent

Method and apparatus for testing magnetic disks

Life of this patent

Abstract

Claims17