Abstract: A method, apparatus, and a storage system are provided for implementing enhanced indirection update for indirected storage devices. A novel remapping command generated by a host is used to store indirection data. The remapping command enables remapping of a set of Logical Block Addresses (LBAs) to a different set of LBAs. The remapping command includes a source LBA, length and a destination LBA.

Abstract: A method and a storage system are provided for implementing deterministic memory allocation for indirection tables for persistent media or disk drives, such as, shingled perpendicular magnetic recording (SMR) indirection tables. A plurality of fixed-size memory pools are used to store indirection data. The distribution of pool allocate sizes is fixed. A pool allocate size is selected based upon an indirection system request size.

Abstract: A method and a storage system are provided for implementing indirection tables for persistent media or disk drives with enhanced emergency power outage (EPO) protection for the indirection data, such as shingled perpendicular magnetic recording (SMR) indirection tables. Chaining of indirection data is provided with one block pointing to another block of the indirection data stored to disk or flash memory. An EPO-safe buffer is used to store a metadata entry responsive to completing each host write command. Each metadata entry is added to a metadata block, a pointer is stored in the EPO-safe buffer to a current metadata block and a previous metadata block. For a next EPO-safe buffer update entries are removed for the previous metadata block, keeping the last two metadata pointers and last metadata block.

Abstract: SMR disk drives with hybrid E-regions that include a nonvolatile solid state memory E-region in addition to the magnetic media E-regions on disk are described. The memory E-region can be used in operations that will be referred as destaging and/or restaging to sequentialize sets of exception records to reduce the time and energy spent in executing seeks in the disk E-region. The ratio of the size of the solid state memory E-region to the total E-region capacity on the disks can be optimized for selected applications according to the invention using tradeoffs between performance and cost. For example, an embodiment with a memory E-region size that is 10% of the total disk E-region capacity achieves substantial performance enhancement over a disk-only E-region implementation and also results in smaller costs than would be required in a NAND-only memory E-region.

Abstract: SMR disk drives with hybrid E-regions that include a nonvolatile solid state memory E-region in addition to the magnetic media E-regions on disk are described. The memory E-region can be used in operations that will be referred as destaging and/or restaging to sequentialize sets of exception records to reduce the time and energy spent in executing seeks in the disk E-region. The ratio of the size of the solid state memory E-region to the total E-region capacity on the disks can be optimized for selected applications according to the invention using tradeoffs between performance and cost. For example, an embodiment with a memory E-region size that is 10% of the total disk E-region capacity achieves substantial performance enhancement over a disk-only E-region implementation and also results in smaller costs than would be required in a NAND-only memory E-region.

Abstract: A method and a storage system are provided for implementing fragmented stream handling for persistent media including shingled disk drives (SDDs). A plurality of Exception Regions for recording stream commands is defined for disk regions. One state is maintained in each of the Exception Regions including a free Exception Region, an active Exception Region, a recovery Exception Region and a used Exception Region. TRIM commands are issued by a host to the drive to indicate deleted content.

Abstract: A method and a storage system are provided for implementing indirection tables and providing enhanced updates of the indirection tables for persistent media or disk drives, such as shingled perpendicular magnetic recording (SMR) indirection tables. A plurality of memory pools are used to store indirection data. An exception pointer table provides a pointer to an exception list for an I-Track. The exception list includes predetermined-size exception entries sorted by an offset from a start of the I-Track. An insert exception entry is provided for a new host write and merged to an updated exception list using an offset of the insert exception entry.

Abstract: An indirection system in a shingled storage device is described that uses an algorithm to map LBAs to DBAs based on a predetermined rule or assumption and then handles as exceptions LBAs that are not mapped according to the rule. The assumed rule is that a fixed-length set of sequential host LBAs are located at the start of an I-track. Embodiments of the invention use two tables to provide the mapping of LBAs to DBAs. The mapping assumed by the rule is embodied in the LBA Block Address Table (LBAT) which gives the corresponding I-track address for each LBA Block. The LBA exceptions are recorded using an Exception Pointer Table (EPT), which gives the pointer to the corresponding variable length Exception List for each LBA Block. The indexing into the LBAT and the EPT is derived from the LBA by a simple arithmetic operation.

Abstract: A method, apparatus, and a storage system are provided for implementing enhanced indirection update for indirected storage devices. A novel remapping command generated by a host is used to store indirection data. The remapping command enables remapping of a set of Logical Block Addresses (LBAs) to a different set of LBAs. The remapping command includes a source LBA, length and a destination LBA.

Abstract: Shingled magnetic recording (SMR) devices are described that include a command processor for accepting commands from the host/user for executing selected SMR related operations, setting selected SMR parameters and reading selected SMR related statistics and status indicators. The commands allow a host/user to control defragmentation and destaging operations. Embodiments include some or all of the set of features allowing selection of formatting settings, selection of optimization settings; command to immediately run defragmentation operation; command to change waiting time before starting defragmentation operation; and command to temporarily suspend defragmentation operation until certain usage threshold is met (e.g., E-region(s) near full).

Abstract: A method and a storage system are provided for implementing fragmented stream handling for persistent media including shingled disk drives (SDDs). A plurality of Exception Regions for recording stream commands is defined for disk regions. One state is maintained in each of the Exception Regions including a free Exception Region, an active Exception Region, a recovery Exception Region and a used Exception Region. TRIM commands are issued by a host to the drive to indicate deleted content.

Abstract: A host operating system (OS) can function as a task under a disk drive operating system. The host OS and the disk drive operating system can be run on a single processor. The processor is able to maintain the real-time response characteristics of a disk drive controller. A shared memory subsystem can be accessed by both operating systems. A disk drive storage device can access and respond to metadata about an underlying file system maintained by a host operating system (OS) to optimize data transfers between the disk drive and the host OS. The disk drive can identify the nature of read/write accesses, allowing it to prioritize and performance optimize the accesses. The disk drive can perform these functions without any changes to the block interface.

Abstract: A method and a storage system are provided for implementing host logical address to physical memory address mapping for persistent storage media including flash memory. Numerical compositions at multiple levels of granularity are used to store the logical address to physical memory address mappings. A plurality of groupings, each grouping including a fixed number of blocks is encoded using recursive composition, eliminating the need to store separate lengths.

Abstract: Shingled magnetic recording (SMR) devices according to embodiments of the invention include unshingled cache regions that can be used for storage of data. The unshingled cache regions can be used in a variety of flexible ways including in an implementation of write-twice caching or for opportunistic temporary storage to improve performance. The cache regions can be offset between top and bottom surfaces of the disk and staggered between disks to provide shorter seek times to the nearest cache region. Embodiments of the invention are adapted for use with symmetric or asymmetric heads.

Abstract: An indirection system in a shingled storage device is described that uses an efficient algorithm to map LBAs to DBAs based on a predetermined rule or assumption and then handles as exceptions LBAs that are not mapped according to the rule. The assumed rule is that a fixed-length set of sequential host LBAs are located at the start of an I-track. Embodiments of the invention use two tables to provide the mapping of LBAs to DBAs. The mapping assumed by the rule is embodied in the LBA Block Address Table (LBAT) which gives the corresponding I-track address for each LBA Block. The LBA exceptions are recorded using an Exception Pointer Table (EPT), which gives the pointer to the corresponding variable length Exception List for each LBA Block. The indexing into the LBAT and the EPT is made efficient by deriving the index from the LBA by a simple arithmetic operation.

Abstract: A method and a storage system are provided for implementing indirection tables for persistent media or disk drives with enhanced emergency power outage (EPO) protection for the indirection data, such as shingled perpendicular magnetic recording (SMR) indirection tables. Chaining of indirection data is provided with one block pointing to another block of the indirection data stored to disk or flash memory. An EPO-safe buffer is used to store a metadata entry responsive to completing each host write command. Each metadata entry is added to a metadata block, a pointer is stored in the EPO-safe buffer to a current metadata block and a previous metadata block. For a next EPO-safe buffer update entries are removed for the previous metadata block, keeping the last two metadata pointers and last metadata block.

Abstract: SMR disk drives with hybrid E-regions that include a nonvolatile solid state memory E-region in addition to the magnetic media E-regions on disk are described. The memory E-region can be used in operations that will be referred as destaging and/or restaging to sequentialize sets of exception records to reduce the time and energy spent in executing seeks in the disk E-region. The ratio of the size of the solid state memory E-region to the total E-region capacity on the disks can be optimized for selected applications according to the invention using tradeoffs between performance and cost. For example, an embodiment with a memory E-region size that is 10% of the total disk E-region capacity achieves substantial performance enhancement over a disk-only E-region implementation and also results in smaller costs than would be required in a NAND-only memory E-region.

Abstract: Shingled magnetic recording (SMR) devices are described that include a command processor for accepting commands from the host/user for executing selected SMR related operations, setting selected SMR parameters and reading selected SMR related statistics and status indicators. The commands allow a host/user to control defragmentation and destaging operations. Embodiments include some or all of the set of features allowing selection of formatting settings, selection of optimization settings; command to immediately run defragmentation operation; command to change waiting time before starting defragmentation operation; and command to temporarily suspend defragmentation operation until certain usage threshold is met (e.g., E-region(s) near full).

Abstract: A method and a storage system are provided for implementing deterministic memory allocation for indirection tables for persistent media or disk drives, such as, shingled perpendicular magnetic recording (SMR) indirection tables. A plurality of fixed-size memory pools are used to store indirection data. The distribution of pool allocate sizes is fixed. A pool allocate size is selected based upon an indirection system request size.

Abstract: SMR disk drives with hybrid E-regions that include a nonvolatile solid state memory E-region in addition to the magnetic media E-regions on disk are described. The memory E-region can be used in operations that will be referred as destaging and/or restaging to sequentialize sets of exception records to reduce the time and energy spent in executing seeks in the disk E-region. The ratio of the size of the solid state memory E-region to the total E-region capacity on the disks can be optimized for selected applications according to the invention using tradeoffs between performance and cost. For example, an embodiment with a memory E-region size that is 10% of the total disk E-region capacity achieves substantial performance enhancement over a disk-only E-region implementation and also results in smaller costs than would be required in a NAND-only memory E-region.