Disk drive having multiple disk surfaces accessible by a read/write head and nonvolatile memory for continuous data transfer
View Patent ↗A magnetic recording hard disk drive (HDD) has at least one read/write head that accesses more than one disk surface. The HDD is able to transfer data to and from the host computer seamlessly without interruption during the time the head is being moved from one disk surface to another disk surface. Nonvolatile solid state memory is associated with pairs of disk surfaces. During the time of a head transfer from one disk surface in the pair to the other disk surface, data is read from or written to the associated nonvolatile memory. The data is first read from or written to one disk surface, then from or to the nonvolatile memory, and then, after completion of the head transfer, from or to the other disk surface, thereby allowing seamless uninterrupted transfer of data.
1. A magnetic recording disk drive comprising:
N magnetic recording disks numbered from 0 to N−1 and rotatable about a common axis, each disk having a front surface and a back surface and at least one disk surface having a plurality of concentric data tracks, each data track including a plurality of contiguous sectors for the storage of data blocks from a host computer, each sector having an associated logical block address (LBA);
a nonvolatile memory having a plurality of addresses for the storage of data blocks from a host computer, each nonvolatile memory address having an associated LBA, wherein the nonvolatile memory has N−2 partitions numbered from 1 to N−2 and associated with disks 1 to N−2, each partition having LBAs numbered consecutively between an LBA on the front surface of its associated disk and the back surface of its associated disk;
first and second read/write heads for writing data blocks to the sectors and reading data blocks from the sectors;
a head actuator connected to the heads for moving the heads across the disk surfaces;
a driver connected to the head actuator for moving the head actuator axially to enable the heads to move in axial gaps between axially-adjacent disks to access different disk surfaces, wherein the first head accesses only the back surfaces of the disks and the second head accesses only the front surfaces of the disks; and
a controller adapted for connection to the host computer for transferring data blocks between the host computer and the sectors on the disk surfaces and addresses in the nonvolatile memory in response to read and write commands from the host computer.
2. The disk drive of claim 1 wherein the controller includes logic for executing method acts comprising, in response to a write command from the host computer:
writing data blocks sequentially with the second head to the LBAs on the front surface of disk 1;
while the driver is moving the head actuator to enable the first head to access the back surface of disk 1, writing data blocks sequentially to the LBAs of partition 1 of the nonvolatile memory; and
while a head is accessing the back surface of disk 1, writing data blocks with the first head sequentially to the LBAs on the back surface of disk 1.
3. The disk drive of claim 1 wherein the controller includes logic for executing method acts comprising, in response to a read command from the host computer:
reading data blocks sequentially with the second head from the LBAs on the front surface of disk 1;
while the driver is moving the head actuator to enable the first head to access the back surface of disk 1, reading data blocks sequentially from the LBAs of partition 1 of the nonvolatile memory; and
while a head is accessing the back surface of disk 1, reading data blocks with the first head sequentially from the LBAs on the back surface of disk 1.
4. A magnetic recording hard disk drive comprising:
a base;
a spindle;
a spindle motor attached to the base for rotating the spindle about an axis of rotation;
a plurality of magnetic recording disks on the spindle, each disk having at least one disk surface having a plurality of concentric data tracks, each data track including a plurality of contiguous sectors for the storage of data blocks from a host computer, each sector having an associated logical block address (LBA);
a nonvolatile memory having a plurality of addresses for the storage of data blocks from a host computer, each nonvolatile memory address having an associated LBA; wherein the LBAs are numbered consecutively from an LBA on a first disk surface through LBAs of the nonvolatile memory to an LBA on a second disk surface;
a disk separator movable axially for separating selected axially-adjacent disks, each pair of axially-adjacent disks defining an axial gap in the disk stack when the disks in a pair are separated;
a rotary actuator on the base and rotatable about an axis generally parallel to the rotational axis of the spindle motor;
a head-arm assembly comprising an arm and at least one read/write head attached to an end of the arm for writing data blocks to the sectors and reading data blocks from the sectors, the head-arm assembly connected to the rotary actuator and rotatable by the rotary actuator generally radially in the axial gaps to enable the head to access tracks on a surface of one of the axially-separated disks;
a driver connected to the rotary actuator for moving the head-arm assembly axially to enable the head-arm assembly to be rotatable in different axial gaps and the head to access different disk surfaces; and
a controller adapted for connection to the host computer for transferring data blocks between the host computer and the sectors on the disk surfaces and addresses in the nonvolatile memory in response to read and write commands from the host computer.
5. The disk drive of claim 4 disk wherein there are N disks numbered axially from 0 to N−1, wherein each disk has a front surface and a back surface, wherein there are first and second heads, wherein the first head accesses only the back surfaces of the disks and the second head accesses only the front surfaces of the disks, wherein the LBAs are numbered consecutively from an LBA on the back surface of disk 0, through an LBA on the front surface of disk 1, through the LBAs of the nonvolatile memory to an LBA on the back surface of disk 1, and wherein the controller includes logic for executing method acts comprising, in response to a write command from the host computer:
writing data blocks sequentially to the LBAs of the front surface of disk 1 with the second head;
while the driver is moving the head actuator to a different axial gap to enable the first head to access the back surface of disk 1, writing data blocks sequentially to the LBAs of the nonvolatile memory; and
writing data blocks sequentially to the LBAs of the back surface of disk 1 with the first head.
6. The disk drive of claim 5 wherein the controller includes logic for executing method acts comprising, in response to a read command from the host computer:
reading data blocks sequentially from the LBAs of the front surface of disk 1 with the second head;
while the driver is moving the head actuator to enable the first head to access the back surface of disk 1, reading data blocks sequentially from the LBAs of the nonvolatile memory; and
reading data blocks sequentially from the LBAs of the back surface of disk 1 with the first head.
7. The disk drive of claim 5 wherein the LBAs are further numbered consecutively from an LBA on the back surface of disk 1 to an LBA on the front surface of disk 2.
8. The disk drive of claim 5 wherein the nonvolatile memory has N−2 partitions numbered from 1 to N−2 and associated with disks 1 to N−2, each partition having LBAs numbered consecutively between an LBA on the front surface of its associated disk and the back surface of its associated disk.
9. A magnetic recording disk drive comprising:
N magnetic recording disks numbered from 0 to N−1 and rotatable about a common axis, each disk having a front surface and a back surface and at least one disk surface having a plurality of concentric data tracks, each data track including a plurality of contiguous sectors for the storage of data blocks from a host computer, each sector having an associated logical block address (LBA);
a nonvolatile memory having a plurality of addresses for the storage of data blocks from a host computer, each nonvolatile memory address having an associated LBA, wherein the LBAs are numbered consecutively from an LBA on a first disk surface through LBAs of the nonvolatile memory to an LBA on a second disk surface;
first and second read/write heads for writing data blocks to the sectors and reading data blocks from the sectors;
a head actuator connected to the heads for moving the heads across the disk surfaces;
a driver connected to the head actuator for moving the head actuator axially to enable the heads to move in axial gaps between axially-adjacent disks to access different disk surfaces, wherein the first head accesses only the back surfaces of the disks and the second head accesses only the front surfaces of the disks; and
a controller adapted for connection to the host computer for transferring data blocks between the host computer and the sectors on the disk surfaces and addresses in the nonvolatile memory in response to read and write commands from the host computer, wherein the controller includes logic for executing method acts comprising, in response to a write command from the host computer:
writing data blocks sequentially to the LBAs of the front surface of disk 1 with the second head;
while the driver is moving the head actuator to enable the first head to access the back surface of disk 1, writing data blocks sequentially to the LBAs of the nonvolatile memory; and
writing data blocks sequentially to the LBAs of the back surface of disk 1 with the first head.
10. The disk drive of claim 9 wherein the LBAs are further numbered consecutively from an LBA on the back surface of disk 1 to an LBA on the front surface of disk 2.