# US 2017/0220264 A1 · Zone forward drive management

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- Number: US 2017/0220264 A1
- Document ID: US20170220264A1
- Status: Published application
- Kind: A1
- Application number: 15/012,526
- Filed: 2016-02-01
- Published: 2017-08-03
- Earliest claimed: 2016-02-01
- Assignees: Seagate Technology LLC
- Applicants: Seagate Technology LLC
- Inventors: Daniel J. Sokolov; Adam J. Weikal; Monish S. Prabhakar
- Web page: https://patentgrep.com/patent/US20170220264A1

## CPC

- G06F 3/0611: {in relation to response time}
- G06F 3/061: {Improving I/O performance}
- G06F 3/064: {Management of blocks}
- G06F 3/0659: {Command handling arrangements, e.g. command buffers, queues, command scheduling}
- G06F 3/0676: {Magnetic disk device}
- G06F 12/0246: {in block erasable memory, e.g. flash memory}
- G06F 12/10: Address translation
- G11B 20/1217: {on discs}
- G06F 2212/1024: Latency reduction
- G06F 2212/21: Employing a record carrier using a specific recording technology
- G06F 2212/70: Details relating to dynamic memory management
- G06F 2212/7202: Allocation control and policies
- G11B 2020/1242: {the area forming one or more zones, wherein each zone is shaped like an annulus or a circular sector}
- G11B 2020/1298: {Enhancement of the signal quality}
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- 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

Various zone forwarding management techniques disclosed herein generally provide efficient methods of data caching, steering, mapping, and migration to reduce write amplification and command latency. In one implementation, a zone-forward storage medium management method includes receiving commands to write data sets to target LBAs included in a consecutive sequence of LBAs, selectively mapping the sequence of LBAs to a plurality of contiguous physical zones, and selectively writing the data sets to the physical zones. Various techniques may be used to migrate valid data of the plurality of physical zones to one physical zone.

## Claims

### Claim 1

A method for managing a storage device, comprising:
receiving a command to write new data to a target LBA included in a consecutive sequence of LBAs mapped to a first contiguous physical zone of a storage medium;
determining that writing the new data to the first contiguous physical zone affects valid data in one or more blocks of the first contiguous physical zone not updated by the command;
based on the determination, mapping the consecutive sequence of LBAs to a second contiguous physical zone while preserving the mapping of the LBAs to the first contiguous physical zone; and
writing the new data to the second contiguous physical zone.

### Claim 2 (depends on 1)

The method of claim 1, wherein writing the new data to the second contiguous physical zone further comprises:
copying a subset of valid data from the first contiguous physical zone to the second contiguous physical zone, wherein the subset includes data of LBAs following the target LBA in the consecutive range of LBAs and the subset excludes data of LBAs preceding the target LBA in the consecutive range of LBAs.

### Claim 3 (depends on 2)

The method of claim 2, wherein copying the subset of valid data further comprises:
copying multiple subsets of valid data to the second contiguous physical zone in multiple separate write operations, wherein the subsets are written to the second contiguous physical zone according to a consecutive track order.

### Claim 4 (depends on 3)

The method of claim 3, wherein the copying of multiple subsets of valid data begins with a subset of data located in a middle region of the first contiguous physical zone.

### Claim 5 (depends on 1)

The method of claim 1, wherein the first contiguous physical zone and the second contiguous physical zone are separate bands of shingled data in a shingled magnetic recording system.

### Claim 6 (depends on 1)

The method of claim 1, further comprising:
receiving sequential write commands to modify data of two or more LBA subsets within the sequential sequence of LBAs; and
writing the data of the two or more LBA subsets to corresponding blocks within the second contiguous physical zone according to a consecutive LBA order.

### Claim 7 (depends on 5)

The method of claim 5, wherein writing the data further comprises:
zero-filling placeholder bits into one or more gaps between the two or more LBA subsets.

### Claim 8 (depends on 6)

The method of claim 6, further comprising:
determining that the first contiguous zone includes valid data corresponding to an LBA gap between between the two or more LBA subsets; and
writing in the second contiguous zone, according to the consecutive LBA order, the data of the two or more LBA subsets and the valid data corresponding to the LBA gap.

### Claim 9 (depends on 1)

The method of claim 1, wherein the data write to the second contiguous physical zone is smaller in size than a size of data currently stored in the first contiguous physical zone.

### Claim 10 (depends on 1)

The method of claim 1, further comprising:
receiving another command to write additional data to a second LBA of the consecutive sequence of LBAs;
writing the additional data to the second contiguous physical zone; and
zero-filling a range of data blocks in the second contiguous physical zone between physical blocks mapped to the target LBA and the second LBA.

### Claim 11 (depends on 1)

The method of claim 1, further comprising:
mapping the consecutive sequence of LBAs to a third contiguous physical zone while preserving the mapping of the LBAs to the first contiguous physical zone and the second contiguous physical zone.

### Claim 12

One or more tangible computer-readable storage media encoding computer-executable instructions for executing on a computer system a computer process, the computer process comprising:
receiving a command to write new data to a target LBA included in a consecutive sequence of LBAs mapped to a first contiguous physical zone of a storage medium;
determining that writing the new data to the first contiguous physical zone affects valid data in one or more blocks of the first contiguous physical zone not updated by the command;
based on the determination, mapping the consecutive sequence of LBAs to a second contiguous physical zone while preserving the mapping of the LBAs to the first contiguous physical zone; and
writing the new data to the second contiguous physical zone.

### Claim 13 (depends on 12)

The one or more tangible computer-readable storage media of claim 12, wherein the computer process further comprises:
copying a subset of valid data from the first contiguous physical zone to the second contiguous physical zone, wherein the subset includes data of LBAs following the target LBA in the consecutive sequence of LBAs and the subset excludes data of LBAs preceding the target LBA in the consecutive sequence of LBAs.

### Claim 14 (depends on 12)

The one or more tangible computer-readable storage media of claim 12, wherein copying the subset of valid data further comprises:
copying multiple subsets of valid data to the second contiguous physical zone in multiple separate write operations, wherein the subsets are written to the second contiguous physical zone according to a consecutive track order.

### Claim 15 (depends on 12)

The one or more tangible computer-readable storage media of claim 12, wherein the first contiguous physical zone and the second contiguous physical zone are separate bands of shingled data in a shingled magnetic recording system.

### Claim 16 (depends on 12)

The one or more tangible computer-readable storage media of claim 12, wherein the computer process further comprises:
migrating valid data of the first contiguous physical zone to the second contiguous physical zone and freeing the first contiguous physical zone from association with the consecutive sequence of LBAs.

### Claim 17

A system comprising:
memory;
at least one processor;
a zone forwarding module stored in the memory and executable by the at least one processor, the zone forwarding module configured to:
receive a command to write new data to a target LBA included in a consecutive sequence of LBAs mapped to a first contiguous physical zone of a storage medium;
map the consecutive sequence of LBAs to a second contiguous physical zone while preserving the mapping of the LBAs to the first contiguous physical zone; and
write the new data to the second contiguous physical zone.

### Claim 18 (depends on 17)

The system of claim 17, wherein the first contiguous physical zone and second contiguous physical zone are zones on an overprovisioned storage drive.

### Claim 19 (depends on 17)

The system of claim 17, wherein the zone forwarding module is further configured to migrate valid data of the second contiguous physical zone back to the first contiguous physical zone and free the second contiguous physical zone from association with the consecutive sequence of LBAs.

### Claim 20 (depends on 17)

The system of claim 17, wherein the one forwarding module is further configured to migrate valid data of the first contiguous physical zone to the second contiguous physical zone and free the first contiguous physical zone from association with the consecutive sequence of LBAs.