Magnetic disk device
AssigneesKabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation
InventorsYuichiro Watanabe, Kazunori Matsuyama
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Abstract
A magnetic disk includes areas to which unique addresses are respectively assigned. A memory is configured to store unprocessed commands. A controller is configured to store, in the memory, a database of a tree-shaped structure. The structure includes a plurality of nodes respectively associated with a plurality of addresses respectively specified by a plurality of unprocessed commands. Two of the plurality of nodes are associated with each other. The controller is further configured to select, of the plurality of unprocessed commands, either a command associated with an address larger than and closest to a start address or a command associated with an address smaller than and closest to the start address as a candidate command to be executed next.
Claims15
A magnetic disk device, comprising:
- a magnetic disk including a plurality of areas to which unique addresses are respectively assigned;
- a memory configured to store a plurality of unprocessed commands;
- and
- a controller configured to:
- store, in the memory, a database of a tree-shaped structure, the structure including a plurality of nodes respectively associated with a plurality of addresses respectively specified by a plurality of unprocessed commands, two of the plurality of nodes being associated with each other;
- and select, of the plurality of unprocessed commands, either a command associated with an address larger than and closest to a start address or a command associated with an address smaller than and closest to the start address as a candidate command to be executed next.
A magnetic disk device, comprising:
- a magnetic disk including a plurality of areas to which unique addresses are respectively assigned;
- a memory configured to store a plurality of unprocessed commands;
- and
- a controller configured to:
- store, in the memory, a database of the plurality of unprocessed commands in the memory;
- repeatedly perform, in each of a first reordering process and a second reordering process:
- a selection of a candidate command to be executed next from among the plurality of unprocessed commands in the memory;
- and a comparison of an execution cost of the candidate command and an execution cost of a command to be executed next;
- and
- search for, in the second reordering process, a candidate for a command to be executed next from among a plurality of unprocessed commands in the memory using an address in an address range selected based on a density of received commands if a number of received commands in a first address range is below a first value, wherein
- the first address range includes addresses for a plurality of candidate commands for which execution costs have been compared with an execution cost of the command to be executed next in the first reordering process.
Dependencies are inferred from the claim text.