Method and apparatus to reduce magneto-resistive drive electromigration and improve drive yields
AssigneeMaxtor Corporation
InventorNelson Cheng
Life of this patent
Estimating the term…
Abstract
Multi-head disk drive system measures head resistances and selects lowest-resistance heads for track-servo operation during sleep mode, thereby substantially prolonging EM lifetime, improving field failure rate, unit production costs, and drive performance and yields.
Claims12
A multi-disk storage apparatus comprising:
- a first disk;
- a second disk;
- a first head associated with the first disk;
- a second head associated with the second disk;
- and
- means for determining a first resistance value associated with the first head and a second resistance value associated with second head, said means selecting the first head or the second head according to the determined resistance values,
- wherein the head having a lowest resistance is selected for performing a track-servo operation during a sleep mode, thereby effectively prolonging electromigration lifetime, improving field failure rate, reducing production cost, or increasing drive performance and yield.
In a multi-disk drive system comprising a head assembly and a plurality of disks, a method for reducing electromigration effect on one or more drive heads, the method comprising the steps of:
- operating a first drive head in a first mode to access a first disk;
- operating a second drive head in a second mode to access a second disk;
- measuring a first resistance of the first drive head and a second resistance of the second drive head;
- and
- determining that the second resistance is less than the first resistance;
- wherein the second mode comprises a quiescent state and
- wherein the second drive head performs a servo-tracking operation of the second disk during the quiescent state.
In a multi-disk drive system comprising a head assembly and a plurality of disks, a method for reducing electromigration effect on one or more drive heads, the method comprising the steps of:
- operating a first drive head in a first mode to access a first disk;
- operating a second drive head in a second mode to access a second disk, the second mode comprising a quiescent state;
- operating a third drive head in a third mode to access a third disk, wherein the third mode comprises a quiescent state;
- measuring a first resistance of the first drive head, a second resistance of the second drive head, and a third resistance of the third drive head;
- determining that the third resistance is less than the first resistance and the second resistance;
- and
- causing the third drive head to perform a servo-tracking operation of the third disk.
An improved disk drive assembly method comprising the steps of:
- measuring a signal associated a first disk head having a first resistance value;
- measuring a second signal associated a second disk head having a second resistance value;
- indicating for an operational mode one or more such disk heads according to the measured signals;
- and
- assembling the first and second disk heads in a disk drive assembly, wherein the operational mode comprises a sleep mode during which each indicated disk head operates for servo-tracking, each indicated disk head having a relatively lower resistance value.
An improved disk drive apparatus comprising:
- a plurality of storage disks;
- a plurality of drive heads, each drive head being associated with a corresponding one of the plurality of storage disks;
- means for determining a resistance value for each of the plurality of drive heads;
- and
- means for selecting the drive head having a lowest resistance value to perform a track-servo operation during a low current operational state, thereby reducing undesirable electromigration effects.
Dependencies are inferred from the claim text.