摘要:
A card information-storing portion is provided in a semiconductor memory card, and information relating to access performance such as access condition and access rate is held in the storing portion. Further, an access device acquires the held information from the semiconductor memory card to make it possible that the information can be used for control of a file system. This optimizes processing of the access device and the semiconductor memory card independent of differences in characteristics of semiconductor memory cards and management methods used, realizing high-rate access from the access device to a semiconductor memory card.
摘要:
A host information memory is provided in a semiconductor memory card and a data write start address and a data size supplied by an access unit are stored. A free physical area generation section determines whether or not to perform erasing of an invalid block of a nonvolatile memory when writing of data based on the data write start address and data size, and determines the number of blocks to be erased. When erasing, writing of data and erasing of invalid blocks are simultaneously performed with respect to different memory chips. Erase process of data, herewith, can be optimized and high speed access from the access unit to a semiconductor memory card can be realized.
摘要:
A card information-storing portion is provided in a semiconductor memory card, and information relating to access performance such as access condition and access rate is held in the storing portion. Further, an access device acquires the held information from the semiconductor memory card to make it possible that the information can be used for control of a file system. This optimizes processing of the access device and the semiconductor memory card independent of differences in characteristics of semiconductor memory cards and management methods used, realizing high-rate access from the access device to a semiconductor memory card.
摘要:
A host information memory is provided in a semiconductor memory card and a data write start address and a data size supplied by an access unit are stored. A free physical area generation section determines whether or not to perform erasing of an invalid block of a nonvolatile memory when writing of data based on the data write start address and data size, and determines the number of blocks to be erased. When erasing, writing of data and erasing of invalid blocks are simultaneously performed with respect to different memory chips. Erase process of data, herewith, can be optimized and high speed access from the access unit to a semiconductor memory card can be realized.
摘要:
A card information storage part (119) is provided in a semiconductor memory device (110) to store information of the characteristics of the semiconductor memory device (110). There is also provided a file system interface control part (120) for performing, based on the stored characteristic information, a file access suitable for the characteristics of the semiconductor memory device (110). This allows an access device (100) to perform an optimum file access via the file system interface control part (120) without awareness of the characteristics of the semiconductor memory device (110).
摘要:
When a file system control part 155A writes file data into a main memory 142, a file can be easily written continuously and the number of file copy can be decreased at updating a directory entry by writing the file data and a directory entry into different allocation units. In this manner, when using a nonvolatile memory in which physical block size as an erase unit is larger than cluster size, the write performance can be enhanced.
摘要:
When a file system control part 155A writes file data into a main memory 142, a file can be easily written continuously and the number of file copy can be decreased at updating a directory entry by writing the file data and a directory entry into different allocation units. In this manner, when using a nonvolatile memory in which physical block size as an erase unit is larger than cluster size, the write performance can be enhanced.
摘要:
A semiconductor memory card 1 includes a user data area 21 and a management information area 22, in a data storing unit 2. According to a writing test command from a memory access device 6, a memory controller 3 writes data into a user data storing area and measures the writing rate, and transmits the measurement result to the memory access device 6 via a host interface unit 4. Thereby, the memory access device 6 can recognize the writing rate.
摘要:
A semiconductor memory card 1 includes a user data area 21 and a management information area 22, in a data storing unit 2. According to a writing test command from a memory access device 6, a memory controller 3 writes data into a user data storing area and measures the writing rate, and transmits the measurement result to the memory access device 6 via a host interface unit 4. Thereby, the memory access device 6 can recognize the writing rate.
摘要:
A memory controller for reducing a time to create an address management table during initialization of a memory card. The memory controller includes a read-write memory for temporarily storing the address management table and a second memory controller for writing, in a nonvolatile memory, an address management table temporarily stored in the read-write memory. The second memory controller also writes address range specifying information that specifies an address range, when a data writing destination is changed from a first address range to a second address range. The memory controller includes an address management table generator for reading distributed management information used for managing a state of at least one physical block included in the destination address range specified by the address range specifying information during initialization, and to generate the address management table based on the distributed management information.