US 8,711,504 B1 · Disk drive with a subset of sectors with reduced write-to-read gap

Abstract

Disk drives are described in which the conventional write-to-read gap is omitted in selected sectors which frees up space that can be used for other purposes including writing a higher number of bits in the user data area in the gapless selected sectors. Alternative embodiments can use the additional space for servo information such as a repeatable run out (RRO) field. Conventional servo sector SID formats can be used for both gapped and gapless SIDs, which means that during seeking and reading operations full SIDs can be read for every wedge. The tradeoff for being able to write data much closer to the gapless SIDs is that the servo system does not detect the SAM or read the TID in the gapless SIDs during write operations.

Claims18

Dependent claims

A method of operating a disk drive having tracks including a plurality of angularly spaced sector identifications (SIDs) including a preamble field, a servo address mark (SAM) field, a track identification (TID) field and a position error signal (PES) burst field, the method comprising:

writing a first set of data bits preceding a selected SID N on the track with the first set of data bits being positioned with a first sized gap between first set of bits of data and SID N;
detecting the SAM field, the TID field and the PES burst field in SID N;
writing a second set of data bits between the SID N and SID N+1 with the second set of data bits being positioned with a second sized gap between the second set of data bits and SID N+1, where the second sized gap is substantially smaller than the first sized gap;
ignoring the SAM field and the TID field in SID N+1;
and
detecting the PES burst field in SID N+1.

3 more elements

A disk drive comprising:

a rotatable disk with a plurality of concentric tracks with a first track including a plurality of angularly spaced sector identifications (SIDs) with each SID including a servo address mark (SAM), a track identification (TID), and a position error signal (PES) burst field, and sectors of data bits recorded between consecutive SIDs, with a first subset of the sectors of data bits being positioned with a write-to-read gap separating the first subset of the sectors of data bits from a subsequent SID in a down-track direction, and a second subset of the sectors of data bits being positioned without a write-to-read gap separating the second subset of the sectors of data bits from a subsequent SID in a down-track direction;
and
a servo system that only reads the PES burst field in a different subsequent SID after a write operation for a different second subset of the sectors of data bits positioned without a write-to-read gap separating the different second subset of the sectors of data bits from the different subsequent SID.

Dependencies are inferred from the claim text.

Disk drive with a subset of sectors with reduced write-to-read gap

Life of this patent

Disk drive with a subset of sectors with reduced write-to-read gap

Life of this patent

Abstract

Claims18