Storage device, information processing device, data access method and program
A storage device includes a recording medium in which data is recorded on a cluster basis, and a memory that stores a file allocation table (FAT) in which disposition information regarding the cluster is recorded.
1. A storage device comprising:
a recording medium that is configured to record data on a cluster basis;
a memory that stores a file allocation table (FAT) having disposition information regarding the data that is recorded on the cluster basis, wherein the memory is separate from the recording medium, and wherein the memory does not store the data that is recorded on the cluster basis;
a communication bus communicatively that directly connects the recording medium to the memory; and
a memory interface directly connected to the memory, the memory interface configured to provide an information processing device access to the FAT stored in the memory.
2. The storage device according to claim 1 , wherein the memory interface includes an address line and a data line, wherein the address line designates an address for data stored in the memory, and wherein the data line provides access to the data stored in the memory at the designated address.
3. The storage device according to claim 2 , wherein the designated address includes a cluster number or a cluster and byte counts that are occupied by a piece of the disposition information stored in the memory.
4. The storage device according to claim 3 , further comprising a second interface including a command line, the second interface is configured to receive a direct memory access (DMA) descriptor from the information processing device via the command line.
5. A system comprising:
a storage device including:
a recording medium that is configured to record data on a cluster basis,
a memory that stores a file allocation table (FAT) having disposition information regarding the data that is recorded on the cluster basis, wherein the memory is separate from the recording medium, and wherein the memory does not store the data that is recorded on the cluster basis,
a communication bus communicatively that directly connects the recording medium to the memory, and
a memory interface directly connected to the memory, the memory interface configured to provide access to the FAT stored in the memory; and
an information processing device including
a control unit that is configured to gain access to a file recorded in the recording medium of the storage device, and
a second memory interface that is configured to communicate with the memory interface of the storage device to access the FAT stored in the memory of the storage device.
6. The system according to claim 5 , wherein communication between the memory interface and the second memory interface includes an address line and a data line, wherein the address line designates an address for data stored in the memory, wherein the data line provides access to the data stored in the memory at the designated address, and wherein the control unit is further configured to acquire the disposition information recorded in the FAT by gaining access, via the data line, to the data stored in the memory at the designated address.
7. The system according to claim 6 , wherein the designated address includes a cluster number for a cluster and byte counts which are occupied by a piece of the disposition information stored in the memory.
8. The system according to claim 6 , wherein the information processing device further includes a direct memory access (DMA) controller that is configured to perform a DMA transfer of a portion of the data that is recorded on the cluster basis in the recording medium of the storage device using a DMA descriptor, wherein the control unit is further configured to generate the DMA descriptor based on the acquired disposition information.
9. A data access method, the method comprising:
designating, by a control unit of an information processing device, an address on an address line between a memory interface of the information processing device and a second memory interface of a storage device; and
acquiring, by the control unit, disposition information of a file allocation table (FAT) stored in a memory of the storage device at the designated address via a data line between the memory interface of the information processing device and the second memory interface of the storage device, wherein the disposition information is regarding data that is recorded on a cluster basis in a recording medium of the storage device,
wherein the memory is separate from the recording medium, wherein the memory does not store the data that is recorded on the cluster basis, wherein the memory is directly connected to the second memory interface, and wherein a communication bus of the storage device directly connects the mrmory to the recording medium.
10. A non-transitory computer readable medium storing a program comprising instructions executable by a processing unit to perform operations comprising:
designating an address on an address line between a memory interface of an information processing device and a second memory interface of a storage device, and
acquiring disposition information of a file allocation table (FAT) stored in a memory of the storage device at the designated address via a data line between the memory interface of the information processing device and the second memory interface of the storage device, wherein the disposition information is regarding data that is recorded on a cluster basis in a recording medium of the storage device,
wherein the memory is separate from the recording medium, wherein the memory does not store the data that is recorded on the cluster basis, wherein the memory is directly connected to the second memory interface, and wherein a communication bus of the storage device directly connects the memory to the recording medium.
11. The non-transitory computer readable medium according to claim 10 , wherein the designated address includes a cluster number for a cluster and byte counts which are occupied by a piece of the disposition information stored in the memory.
12. The non-transitory computer readable medium according to claim 10 , further comprising instructions executable by the processing unit to perform the operations comprising:
generating a direct memory access (DMA) descriptor based on the acquired disposition information; and
controlling a direct memory access controller (DMAC) to perform a DMA transfer of a portion of the data that is recorded on the cluster basis in the recording medium of the storage device using the DMA descriptor.
13. The data access method according to claim 9 , wherein the designated address includes a cluster number for a cluster and byte counts which are occupied by a piece of the disposition information stored in the memory.
14. The data access method according to claim 9 , further comprising:
generating, by the control unit, a direct memory access (DMA) descriptor based on the acquired disposition information; and
controlling, by the control unit, a direct memory access controller (DMAC) to perform a DMA transfer of a portion of the data that is recorded on the cluster basis in the recording medium of the storage device using the DMA descriptor.
15. The storage device according to claim 1 , further comprising a housing, wherein the recording medium and the memory are internally disposed within the housing.
16. The system according to claim 5 , wherein the storage device has a first housing, and wherein the information processing device has a second housing that is different than the first housing.
17. The data access method according to claim 9 , wherein the recording medium and the memory are internally disposed within a housing of the storage device.