# US 10,319,405 B2 · Overlap detection for magnetic disks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,319,405 B2 - Document ID: US10319405B2 - Status: Granted - Kind: B2 - Application number: 15/938,357 - Filed: 2018-03-28 - Published: 2018-11-22 - Granted: 2019-06-11 - Earliest claimed: 2017-05-18 - Assignees: Seagate Technologies LLC - Applicants: Seagate Technology LLC - Inventors: Chris R. Fulkerson; Abhay T. Kataria - Web page: https://patentgrep.com/patent/US10319405B2 ## CPC - G11B 19/041: {Detection or prevention of read or write errors} - G11B 5/012: Recording on, or reproducing or erasing from, magnetic disks (G11B17/00, G11B19/00 take precedence) - G11B 20/10009: {Improvement or modification of read or write signals} - G11B 20/1217: {on discs} - G11B 20/18: Error detection or correction; Testing {, e.g. of drop-outs} - G11B 2020/10898: {Overwriting or replacing recorded data} - G11B 2020/1869: {Preventing ageing phenomena from causing data loss, e.g. by monitoring the age of record carriers or by recognising wear, and by copying information elsewhere when a record carrier becomes unreliable} - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) ## Abstract Embodiments described herein provide an apparatus that is operable with a storage system. The storage system includes a controller operable to assign a pointer to a first track of a magnetic disk when data is written to the first track. The pointer points to the end of the data in the first track. The controller is also operable to detect a successive write to an earlier written portion of the first track, to update a location of the pointer based on the successive write to the earlier written portion of the first track, to increment a write count of the first track based on the successive write to the earlier written portion of the first track, and to rewrite a track adjacent to the first track when the write count breaches a threshold number. ## Claims ### Claim 1 A storage system, comprising: a controller operable to assign a pointer to a first track of a magnetic disk when data is written to the first track, the pointer pointing to the end of the data in the first track, the controller being further operable to detect a successive write to an earlier written portion of the first track, to update a location of the pointer based on the successive write to the earlier written portion of the first track, to increment a write count of the first track based on the successive write to the earlier written portion of the first track, and to rewrite a track adjacent to the first track when the write count breaches a threshold number. ### Claim 2 (depends on 1) The storage system of claim 1, wherein: the controller is further operable to determine that the writes to the first track are to a same location of the previously written location of the first track, and to change how the write count is incremented. ### Claim 3 (depends on 1) The storage system of claim 1, wherein: the controller is further operable to assign a bit set to the first track that includes a sector identification of the first track and the write count of the first track. ### Claim 4 (depends on 3) The storage system of claim 3, wherein: a number of bits of a bit set at the inner diameter of the magnetic disk is less than a number of bits of a bit set at the outer diameter of the magnetic disk. ### Claim 5 (depends on 1) The storage system of claim 1, wherein: the controller is further operable to generate an overlap check bitmask indicating a previously written portion of the first track, to generate a write check bitmask based on the writes to the first track, and to increment the write count based on a comparison of the overlap check bitmask with the write check bitmask. ### Claim 6 (depends on 1) The storage system of claim 1, wherein: the controller is further operable to reset the write count after the track adjacent to the first track is rewritten. ### Claim 7 (depends on 1) The storage system of claim 1, wherein: the controller is further operable to read data from the track adjacent to the first track, and to correct the data with an error correction code prior to rewriting the data to the track adjacent to the first track. ### Claim 8 A method, comprising: assigning a pointer to a first track of a magnetic disk when data is written to the first track, the pointer pointing to the end of the data in the first track; detecting a successive write to an earlier written portion of the first track; updating a location of the pointer based on the successive write to the earlier written portion of the first track; incrementing a write count of the first track based on the successive write to the earlier written portion of the first track; and rewriting a track adjacent to the first track when the write count breaches a threshold number. ### Claim 9 (depends on 8) The method of claim 8, further comprising: determining that the writes to the first track are to a same location of the previously written location of the first track; and changing how the write count is incremented. ### Claim 10 (depends on 8) The method of claim 8, further comprising: assigning a bit set to the first track that includes a sector identification of the first track and the write count of the first track. ### Claim 11 (depends on 10) The method of claim 10, wherein: a number of bits of a bit set at the inner diameter of the magnetic disk is less than a number of bits of a bit set at the outer diameter of the magnetic disk. ### Claim 12 (depends on 8) The method of claim 8, further comprising: generating an overlap check bitmask indicating a previously written portion of the first track; generating a write check bitmask based on the writes to the first track; and incrementing the write count based on a comparison of the overlap check bitmask with the write check bitmask. ### Claim 13 (depends on 8) The method of claim 8, further comprising: resetting the write count after the track adjacent to the first track is rewritten. ### Claim 14 (depends on 8) The method of claim 8, further comprising: reading data from the track adjacent to the first track; and correcting the data with an error correction code prior to rewriting the data to the track adjacent to the first track. ### Claim 15 A non-transitory computer readable medium comprising instructions that, when executed by a storage controller, direct the storage controller to: assign a pointer to a first track of a magnetic disk when data is written to the first track, the pointer pointing to the end of the data in the first track; detecting a successive write to an earlier written portion of the first track; update a location of the pointer based on the successive write to the earlier written portion of the first track; increment a write count of the earlier written portion of the first track based on the successive write to the first track; and rewrite a track adjacent to the first track when the write count breaches a threshold number. ### Claim 16 (depends on 15) The computer readable medium of claim 15, further comprising instructions that direct the storage controller to: determine that the writes to the first track are to a same location of the previously written location of the first track; and change how the write count is incremented. ### Claim 17 (depends on 15) The computer readable medium of claim 15, further comprising instructions that direct the storage controller to: assign a bit set to the first track that includes a sector identification of the first track and the write count of the first track. ### Claim 18 (depends on 17) The computer readable medium of claim 17, wherein: a number of bits of a bit set at the inner diameter of the magnetic disk is less than a number of bits of a bit set at the outer diameter of the magnetic disk. ### Claim 19 (depends on 15) The computer readable medium of claim 15, further comprising instructions that direct the storage controller to: generate an overlap check bitmask indicating a previously written portion of the first track; generate a write check bitmask based on the writes to the first track; and increment the write count based on a comparison of the overlap check bitmask with the write check bitmask. ### Claim 20 (depends on 15) The computer readable medium of claim 15, further comprising instructions that direct the storage controller to: reset the write count after the track adjacent to the first track is rewritten.