Shingled magnetic recording drive that updates media cache data in-place
View Patent ↗When a shingled magnetic recording (SMR) hard disk drive (HDD) receives a write command that references one or more target logical block addresses (LBAs) and determines that one or more target LBAs are included in a range of LBAs for which data are stored in a memory of the drive, additional data are written to the media cache of the SMR HDD along with the write data during the same disk access. The additional data include data that are stored in the volatile memory and are associated with one or more LBAs that are adjacent in LBA space to the target LBAs. The one or more LBAs that are adjacent in LBA space to the target LBAs may include a first group of LBAs that is adjacent to and follows the target LBAs and a second group of LBA that is adjacent to and precedes the target LBAs.
1. A disk drive comprising:
a shingled magnetic recording (SMR) region;
a conventional magnetic recording (CMR) region;
a volatile memory; and
a controller configured to
in response to a write command from a host, wherein the write command references a first logical block address (LBA) in a logical address space associated with the disk drive and includes first data associated with the first LBA, and the write command is received when second data associated with a second LBA that is adjacent in the logical address space to the first LBA is stored in the CMR region, determine whether the volatile memory stores data associated with the first LBA and the second data, and
upon determining that the volatile memory stores the data associated with the first LBA and the second data, sequentially write the first data to a first physical location in the CMR region and the second data to a second physical location in the CMR region that is adjacent to the first physical location and is different from a third physical location in the CMR region in which the second data is also stored.
2. The disk drive of claim 1 , wherein the controller sequentially writes the first data to the first physical location and the second data to the second physical location during a single disk access operation.
3. The disk drive of claim 1 , wherein the controller is configured to sequentially write third data to a third physical location in the CMR region that is adjacent to one of the first and second physical locations, the third data being stored in the volatile memory before receiving the write command and associated with a set of LBAs that are contiguous in the logical address space with the first LBA.
4. The disk drive of claim 3 , wherein the controller is further configured to:
upon receiving a read command that references the set of LBAs, retrieve valid data for the set of LBAs from one of the SMR region and the CMR region, and store the valid data in the volatile memory,
wherein the third data includes at least a portion of the valid data.
5. The disk drive of claim 3 , wherein the set of LBAs includes LBAs in a first LBA range that is adjacent to and follows the first LBA in logical address space and a second LBA range that is adjacent to and precedes the first LBA in the logical address space.
6. The disk drive of claim 4 , wherein the controller is further configured to determine from a history of commands received from the host, that the read command includes the set of LBAs.
7. The disk drive of claim 6 , wherein retrieving valid data for the set of LBAs from one of the SMR region and the CMR region comprises retrieving valid data for the set of LBAs from both the SMR region and the CMR region.
8. The disk drive of claim 1 , wherein the first physical location comprises a first sector in the CMR region and the second physical location comprises a second sector in the CMR region.
9. The disk drive of claim 1 , wherein the data associated with the first LBA and the first data are prior and current versions of the data associated with the first LBA, respectively.