Data management and control system in semiconductor flush memory and semiconductor flush memory accommodation apparatus

Abstract

Service life of a semiconductor flush memory is extended by averaging the number of times of rewrite operation and non-uniformity of time associated with a synchronization processing is eliminated. The invention provides a mapping rule such that when a space bitmap recorded to a semiconductor flush memory spreads over three erase blocks in the semiconductor flush memory using a UDF file system as a file system, a Root directory is recorded to partial DSA1 corresponding to partial SBM1, a first file directory group is recorded to only partial DSA1 and partial DSA2 corresponding to partial SBM1 and partial SBM2, and a second file directory group is recorded to only partial DSA1 and partial DSA3 corresponding to partial SBM1 and partial SBM3.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a directory structure for explaining a mapping rule applied to a data management and control system according to a first embodiment of the invention;

FIG. 2 is a view showing a directory structure to which file data recorded on a semiconductor flush memory belongs;

FIG. 3 is a view useful for explaining a file management method when the directory structure shown in FIG. 2 is expressed by a UDF file system specification;

FIG. 4 is a block diagram showing a construction of a semiconductor flush memory accommodation apparatus that uses the data management and control system according to the first embodiment of the invention;

FIG. 5 is a view useful for explaining the operation of the semiconductor flush memory accommodation apparatus according to the first embodiment of the invention;

FIG. 6 is a view useful for explaining a monitor camera apparatus as an application example of the semiconductor flush memory accommodation apparatus according to the first embodiment of the invention;

FIG. 7 is a view useful for explaining a directory structure when the mapping rule according to the first embodiment of the invention is applied to a monitor camera apparatus;

FIG. 8 is a view showing a directory structure for explaining a mapping rule according to a second embodiment of the invention; and

FIG. 9 is a view useful for explaining a directory structure when the mapping rule according to the second embodiment of the invention is applied to a monitor camera apparatus.

Claims

1. A data management and control system in a semiconductor flush memory for executing data erasure in a block unit, wherein: a data storage area for storing file data stipulated by a file system and a space bitmap representing a use condition of said data storage area and constituted by a plurality of partial space bitmaps in the block unit are formed in said semiconductor flush memory;said partial space bitmaps correspond to partial data storage areas divided in said data storage area, respectively; anda mapping rule for associating file directory groups so assorted as to correspond to the number of said partial space bitmaps with said partial data storage areas and having partial data storage areas to which one file directory group cannot be recorded in such a fashion as to spread over other storage areas is set.

2. A data management and control system according to claim 1, wherein said file system is based on a UDF file system specification.

3. A data management and control system according to claim 2, wherein said mapping rule contains a root directory in said file data when the number of said partial space bitmaps is N (N≧3), divides said file directories below said root directory into N file directory groups without allowing said file directories to overlap with one another, manages said root directory by a first partial space bitmap, manages an Mth (1<M<N) file directory group by the first and Mth partial space bitmaps and records said Mth file directory group to only the first and Mth partial data storage areas.

4. A data management and control system according to claim 2, wherein said mapping rule contains only once a root directory in said file data when the number of said partial space bitmaps is N (N≧2), divides said file directories below said root directory into N file directory groups without allowing said file directories to overlap with one another, manages said root directory by a first partial space bitmap, manages an Mth (1<M<N) file directory group by the Mth partial space bitmap and records said Mth file directory group to only the Mth partial data storage areas.

5. A semiconductor flush memory accommodation apparatus comprising: a semiconductor flush memory forming a data storage area for storing file data stipulated by a file system, and a space bitmap representing a use condition of said data storage area and constituted by a plurality of partial space bitmaps in a block unit;a system memory for storing information for a synchronization processing with said space bitmap to look up or change said space bitmap and temporarily storing file the data;data management means containing a data arrangement management portion for associating file directory groups so assorted as to correspond to the number of said partial space bitmaps with said partial data storage areas and providing a mapping rule having partial data storage areas to which one file directory group cannot be recorded in such a fashion as to spread over other areas, and managing a UDF file system and the space bitmap; anddata control means for controlling a data flow between said system memory and said semiconductor flush memory.

6. A monitor camera apparatus comprising: a semiconductor flush memory forming a data storage area for storing file data stipulated by a file system, and a space bitmap representing a use condition of said data storage area and constituted by a plurality of partial space bitmaps in a block unit;a system memory for storing information for a synchronization processing with said space bitmap to look up or change said space bitmap and temporarily storing file the data;data management means containing a data arrangement management portion for associating file directory groups so assorted as to correspond to the number of said partial space bitmaps with said partial data storage areas and providing a mapping rule having partial data storage areas to which one file directory group cannot be recorded in such a fashion as to spread over other areas, and managing a UDF file system and the space bitmap;data control means for controlling a data flow between said system memory and said semiconductor flush memory;image processing means for acquiring images or sound; andnetwork connection means for establishing connection with network connection means,wherein said file directory group includes image information divided by a plurality of weekdays.

7. A data management and control method in a semiconductor flush memory for executing data erasure in a block unit, comprising the steps of: forming a data storage area for storing file data stipulated by a file system and a space bitmap representing a use condition of said data storage area and constituted by a plurality of partial space bitmaps in the block unit for said semiconductor flush memory; andsetting a mapping rule for associating a directory structure of said file data with partial data storage areas divided by said data storage area;wherein said mapping rule contains a root directory of said directory structure when the number of said partial space bitmaps is N (N≧3), and divides said file directories below said root directory into N file directory groups without allowing said file directories to overlap with one another, manages said root directory by a first partial space bitmap and executes recording to only a first partial data storage area corresponding to said partial space bitmap, manages an Mth (1<M<N) file directory group by the first and Mth partial space bitmaps and executes recording to the first and Mth partial data storage areas corresponding to said partial space bitmap; andwherein said Mth file directory group cannot be recorded in such a fashion as to spread over Mth and Lth (L: an integer smaller than N with the exception of 1 and M) partial data storage areas.

8. A data management and control method in a semiconductor flush memory for executing data erasure in a block unit, comprising the steps of: forming a data storage area for storing file data stipulated by a file system and a space bitmap representing a use condition of said data storage area and constituted by a plurality of partial space bitmaps in the block unit for said semiconductor flush memory; andsetting a mapping rule for stipulating association between a directory structure of said file data and partial data storage areas divided by said data storage area;wherein said mapping rule contains only once a root directory of said directory structure when the number of said partial space bitmaps is N (N≧2), divides said file directories below said root directory into N file directory groups without allowing said file directories to overlap with one another, manages said root directory by a first partial space bitmap and executes recording to only a first partial data storage area corresponding to said partial space bitmap, manages an Mth (1<M<N) file directory group by an Mth partial space bitmaps and executes recording to only said Mth partial data storage area corresponding to said partial space bitmap; andwherein said Mth file directory group cannot be recorded in such a fashion as to spread over other partial data storage areas than said Mth partial data storage area.