Abstract: Embodiments of servo systems for disk drives are described that include servo identifiers (SIDs) that can be used in mini-mode with a shortened servo gate window that skips over the initial fields in the SID. The SID embodiments include a Servo Address Mark (SAM), Track-ID (TID), P and Q PES bursts, and one or more Integrated Servo sequences that provide a Servo Track Mark (STM) that is detectable in mini-mode. The Integrated Servo sequences can also provide additional PES information, as well as, sector identification information. In one embodiment the servo pattern includes only one IS sequence (which is aligned with the P-Burst) and the Q-Burst is made longer than the P-Burst. The additional number of cycles (bits) in the Q-Burst increases the equivalent number of bits in the PES to compensate for the lack of the second IS sequence.

Abstract: Disk drives with servo systems are described that include a servo ID pattern (SID) with a SAM field, as well as, one or more Integrated Servo sequences designed to provide a redundant sync mark function. The write-to-read gaps are omitted before selected servo sector SIDs. For example, write-to-read gaps can be omitted before alternating servo sector SIDs. When in write-mode that allows writing an extended user data sector without a write-to-read gap, the servo system delays the servo gate assertion with respect to the following SID to accommodate the absence of the write-to-read gap, which means that the SAM field cannot be read, but the Integrated Servo sequence(s) can be read and detected by the digital filters. Embodiments of the invention include sync mark timing for each SID (not just every other SID) even when writing extended user data sectors by using the Integrated Servo sequences to provide a sync timing function.

Abstract: Disk drives are described that include a hybrid servo patterns in which the augmented servo burst fields, which can be Integrated Servo sequences, that provide the PES and also supply additional information such as a SAM, LSBs of the track identifier (TID), sector number, depending on the specific embodiment. Embodiments without write-to-read gaps before the servo sector SIDs are described. The augmented servo burst fields can be read after gapless writing of the preceding data area. For seeking operations the needed bits of the TID without having to detect or decode the Integrated Servo sequences or other augmented servo burst fields. Depending on the embodiment all or the most significant bits of the track identifier can be obtained during seeks by reading the TID fields passing under a read head as the read head moves across tracks without having to detect or decode the Integrated Servo sequences.

Abstract: Disk drives are described that include a hybrid servo patterns in which the augmented servo burst fields, which can be Integrated Servo sequences, that provide the PES and also supply additional information such as a SAM, LSBs of the track identifier (TID), sector number, depending on the specific embodiment. Embodiments without write-to-read gaps before the servo sector SIDs are described. The augmented servo burst fields can be read after gapless writing of the preceding data area. For seeking operations the needed bits of the TID without having to detect or decode the Integrated Servo sequences or other augmented servo burst fields. Depending on the embodiment all or the most significant bits of the track identifier can be obtained during seeks by reading the TID fields passing under a read head as the read head moves across tracks without having to detect or decode the Integrated Servo sequences.

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.