Abstract: A disk drive is disclosed comprising a disk, a head, and a ramp located near an outer periphery of the disk. The disk drive further comprises control circuitry operable to load the head off the ramp over the disk, receive an unload command to perform an unload operation, evaluate a number of unloads relative to an unload limit that varies over time, and when the number of unloads exceeds the unload limit, delay the unload operation.

Abstract: A disk drive is disclosed comprising a non-volatile write cache and a head actuated over a disk. A plurality of write commands are received from a host, wherein each write command comprises write data. A workload for a non-cache area of the disk is determined, and when the workload for the non-cache area of the disk is less than a threshold independent of a workload for the write cache, substantially all of the write data is stored in the non-cache area of the disk. When the workload for the non-cache area of the disk is greater than the threshold independent of the workload for the write cache, a first percentage of the write data is stored in the non-volatile write cache and a second percentage of the write data is stored in the non-cache area of the disk, wherein the first percentage is proportional to the workload for the non-cache area of the disk.

Abstract: Systems and methods for writing a sequence of data to a disk drive using sorted data zones are provided. One embodiment includes a disk drive comprising one or more disks having a plurality of disk surfaces, wherein each disk surface comprises a plurality of data zones, each data zone having a data transfer rate; a plurality of heads, wherein each head is configured to write data to a respective one of the disk surfaces; and a controller configured to operate the plurality of heads to sequentially write a sequence of data blocks to the plurality of disk surfaces in accordance with an order of head-zone combinations ordered from highest data transfer rate to lowest data transfer rate, each head-zone combination corresponding to one of the heads and one of the data zones of the respective disk surface.

Abstract: A data storage device is disclosed comprising a non-volatile memory and control circuitry operable to evaluate a physical feature of the data storage device, wherein the physical feature is physically alterable by a user. When the physical feature is in a first state, host access to first secure data stored in the non-volatile memory is enabled, and when the physical feature is in a second state, the host access to the first secure data is disabled and host access to second data stored in the non-volatile memory is enabled.

Abstract: A hybrid drive is disclosed comprising a head actuated over a disk, and a non-volatile semiconductor memory (NVSM). When a write command is received from a host that is mapped to the NVSM, the write command is serviced by writing data to the NVSM, and when a life remaining of the NVSM falls below a threshold, by also writing a copy of the data to the disk.

Abstract: A hybrid drive is disclosed comprising a head actuated over a disk, and a non-volatile semiconductor memory (NVSM). A first execution time needed to execute commands in a NVSM command queue is estimated, and a second execution time needed to execute commands in a disk command queue is estimated. An access command is inserted into a selected one of the NVSM command queue and the disk command queue in response to the first and second execution times, and one of the first and second execution times is updated in response to an estimated execution time of the access command.

Abstract: Systems and methods for writing a sequence of data to a disk drive using sorted data zones are provided. In one embodiment, a multi-head disk drive comprises a plurality of disk surfaces, wherein each disk surface comprises a plurality of data zones, each data zone having a data transfer rate different from the other zones of the respective disk surface. The multi-head disk drive also comprises a head assembly comprising a plurality of heads, wherein each head is configured to write data to a respective one of the disk surfaces, and a controller configured to operate the plurality of heads to sequentially write a sequence of data blocks to the plurality of disk surfaces in accordance with a list of head-zone combinations ordered from highest data rate to lowest data rate, each head-zone combination corresponding to one of the heads and a data zone of the respective disk surface.

Abstract: A hybrid drive is disclosed comprising a head actuated over a disk, and a non-volatile semiconductor memory (NVSM). A write command is received from a host, the write command comprising data. First and second error correction code (ECC) symbols are generated over the data, wherein the second ECC symbols are different than the first ECC symbols. The data and first ECC symbols are written to the NVSM, and the second ECC symbols are written to the disk.

Abstract: A data storage device is disclosed comprising a non-volatile memory, a logical block address (LBA) table for storing plaintext data used to access the non-volatile memory, and control circuitry including a secure processor and a device processor. The secure processor is operable to initialize the LBA table with at least one authentication code over the plaintext data, and verify the authentication code over the plaintext data. The device processor is operable to receive an access command from a host, evaluate the plaintext data in the LBA table to determine whether to allow the access command, and when the access command is allowed, execute the access command.

Abstract: A hybrid drive is disclosed comprising a non-volatile semiconductor memory (NVSM) comprising a plurality of blocks, and a head actuated over a disk comprising a plurality of tracks, each track comprising a plurality of data sectors. A garbage collection operation is executed on the NVSM by reading valid data from a first block of the NVSM, writing the valid data to the disk, and erasing the first block.

Abstract: Servo-related tasks are performed at a first processor in a disk drive. A signal indicative of an environmental condition is received at the first processor, and code associated with the environmental condition is identified based at least in part on the signal. A second processor in the disk drive is caused to execute the code associated with the environmental condition, and a responsive task is performed at the first processor based at least in part on the executed code associated with the environmental condition.

Abstract: A host activity measure indicative of a frequency of disk access commands received by a disk drive is determined, and then compared against a host activity threshold. A subsystem activity measure indicative of an activity level of a disk drive subsystem is also determined, and then compared against a subsystem activity threshold. Based at least in part on a determination that 1) the host activity measure is indicative of a greater frequency of disk access commands than the host activity threshold, and 2) the subsystem activity measure is indicative of less activity than the subsystem activity threshold, an operating frequency of a disk drive processor is increased.

Abstract: A data storage device is disclosed comprising a non-volatile memory and control circuitry operable to evaluate a physical feature of the data storage device, wherein the physical feature is physically alterable by a user. When the physical feature is in a first state, host access to first secure data stored in the non-volatile memory is enabled, and when the physical feature is in a second state, the host access to the first secure data is disabled and host access to second data stored in the non-volatile memory is enabled.

Abstract: A disk drive is disclosed which receives a plurality of access commands from a host, where each access command identifies a target track. The access commands are stored in a command queue, and for each command in the command queue, a seek length is computed corresponding to a number of tracks between a current track the head is over and the target track of the access command. A seek time is computed in response to the seek length using a seek profile comprising a first plurality of seek length segments and a variance group comprising a second plurality of seek length segments. Each seek length segment corresponds to a range of seek lengths, and the first plurality of seek length segments is different than the second plurality of seek length segments.