Data storage device with write caching for maximizing disk access during laser diode steady state
Various illustrative aspects are directed to a data storage device, method, and one or more processing devices that are configured to: maintain respective measures of write commands associated with respective ones of shingled magnetic recording (SMR) zones defined in a data storage device, wherein data associated with the write commands is stored in a write cache associated with the data storage device; select one of the SMR zones based on the respective measures; perform a pre-heat operation of a laser diode included in a head associated with the selected one of the SMR zones; and perform a continuous write operation in the selected one of the SMR zones following the pre-heat operation, wherein the continuous write operation writes at least a portion of data stored in the write cache associated with the selected one of the SMR zones.
1. A data storage device, comprising:
one or more disks;
an actuator mechanism configured to position a selected head among one or more heads proximate to a corresponding disk surface of a corresponding disk among the one or more disks; and
one or more processing devices, individually or in combination, configured to:
maintain respective measures of write commands associated with respective ones of shingled magnetic recording (SMR) zones defined in the data storage device, wherein data associated with the write commands is stored in a write cache associated with the data storage device;
select one of the SMR zones based on the respective measures;
perform a pre-heat operation of a laser diode included in a head associated with the selected one of the SMR zones; and
perform a continuous write operation in the selected one of the SMR zones following the pre-heat operation, wherein the continuous write operation writes at least a portion of data stored in the write cache associated with the selected one of the SMR zones.
2. The data storage device of claim 1 , wherein the respective measures comprise respective amounts of the data stored in the write cache and associated with respective ones of the SMR zones.
3. The data storage device of claim 2 , wherein the selecting comprises selecting one of the SMR zones that has a largest amount of data stored in the write cache.
4. The data storage device of claim 2 , wherein the selecting comprises selecting one of the SMR zones that has a largest ratio of amount of data stored in the write cache to an amount of time associated with writing the amount of data to the one of the one or more disks.
5. The data storage device of claim 2 , wherein the selecting is performed based on determining a caching condition is satisfied.
6. The data storage device of claim 5 , wherein the caching condition comprises one of:
a respective amount of data stored in the write cache and associated with a respective one of the SMR zones exceeds an individual threshold;
a sum of respective amounts of data stored in the write cache for all the SMR zones exceeds a combined threshold; or
the data storage device has excess write capacity.
7. The data storage device of claim 1 , wherein the performing the pre-heat operation of the laser diode raises a temperature of the laser diode to a steady state thermal condition corresponding to a mode hop resistant temperature.
8. The data storage device of claim 7 , wherein the temperature of the laser diode avoids crossing a mode hop threshold temperature while the laser diode is in the steady state thermal condition.
9. The data storage device of claim 1 , wherein the portion of the data stored in the write cache and associated with the selected one of the SMR zones comprises a largest portion of the data stored in the write cache and associated with the selected one of the SMR zones that ends at an end of track boundary in the selected one of the SMR zones.
10. The data storage device of claim 1 , wherein a number of the SMR zones is limited to less than a maximum number of SMR zones associated with the data storage device.
11. A method comprising:
maintaining respective measures of write commands associated with respective ones of shingled magnetic recording (SMR) zones defined in a data storage device, wherein data associated with the write commands is stored in a write cache associated with the data storage device;
selecting one of the SMR zones based on the respective measures;
performing a pre-heat operation of a laser diode included in a head associated with the selected one of the SMR zones; and
performing a continuous write operation in the selected one of the SMR zones following the pre-heat operation, wherein the continuous write operation writes at least a portion of data stored in the write cache associated with the selected one of the SMR zones,
wherein the maintaining, the selecting, the performing the pre-heat operation, and the performing the continuous write operation are performed by one or more processing devices individually or in combination.
12. The method of claim 11 , wherein the respective measures comprise respective amounts of data stored in the write cache and associated with respective ones of the SMR zones.
13. The method of claim 12 , wherein the selecting comprises selecting one of the SMR zones that has a largest amount of data stored in the write cache.
14. The method of claim 12 , wherein the selecting comprises selecting one of the SMR zones that has a largest ratio of amount of data stored in the write cache to an amount of time associated with writing the amount of data to the disk.
15. The method of claim 12 , wherein the selecting is performed based on determining a caching condition is satisfied, wherein the caching condition comprises one of:
a respective amount of data stored in the write cache and associated with a respective one of the SMR zones exceeds an individual threshold;
a sum of respective amounts of data stored in the write cache for all the SMR zones exceeds a combined threshold; or
the data storage device has excess write capacity.
16. The method of claim 11 , wherein the performing the pre-heat operation of the laser diode raises a temperature of the laser diode to a steady state thermal condition corresponding to a mode hop resistant temperature.
17. One or more processing devices comprising, individually or in combination:
means for maintaining respective measures of write commands associated with respective ones of shingled magnetic recording (SMR) zones defined in a data storage device, wherein data associated with the write commands is stored in a write cache associated with the data storage device;
means for selecting one of the SMR zones based on the respective measures;
means for performing a pre-heat operation of a laser diode included in a head associated with the selected one of the SMR zones; and
means for performing a continuous write operation in the selected one of the SMR zones following the pre-heat operation, wherein the continuous write operation writes at least a portion of data stored in the write cache associated with the selected one of the SMR zones.
18. The one or more processing devices of claim 17 , wherein:
the respective measures comprise respective amounts of data stored in the write cache and associated with respective ones of the SMR zones; and
the selecting comprises selecting one of the SMR zones that has a largest amount of data stored in the write cache.
19. The one or more processing devices of claim 17 , wherein the performing the pre-heat operation of the laser diode raises a temperature of the laser diode to a steady state thermal condition in which the temperature of the laser diode avoids crossing a mode hop threshold temperature during the continuous write operation.
20. The one or more processing devices of claim 17 , wherein a number of the SMR zones is limited to less than a maximum number of SMR zones associated with the data storage device.