BRIEF DESCRIPTION OF THE DRAWINGS
Characteristics and advantage of the present invention will be more clearly understood by referring to accompanied drawings wherein:
FIG. 1 is a system view illustrating a method to access storage device through universal serial bus according to the present invention.
FIG. 2 is a view illustrating the logic memory structure and the mapping table based on which a method to access storage device through universal serial bus according to the present invention can be realized.
FIG. 3 is a flow chart illustrating an embodiment of a method to access storage device through universal serial bus according to the present invention.
FIG. 4 is a flow chart illustrating another embodiment of a method to access storage device through universal serial bus according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a system view illustrating a method to access storage device through universal serial bus according to the present invention. As shown in FIG. 1, in a method to access storage device through universal serial bus (USB) a flash disk 5 is utilized as the storage device in the present invention. The USB flash disk 5 includes a flash controller 4 and a USB plug 3. When using the method of the present invention to access storage device through USB, the USB plug 3 is connected to a USB interface 2 of a computer 1. The computer 1 outputs an access (read/write) instruction to the flash controller 4, and the flash controller 4 decides which data contained in the access instruction is needed to be temporarily saved into the flash random access memory and determines a priority order of the access instruction according to a mapping table of a flash file system. Finally, the flash controller 4 executes the access instruction according to its priority order, writingthe data temporarily saved in the flash random access memory into the flash memory.
FIG. 2 is a view illustrating a logic memory structure 11 and a mapping table 17 based on which a method to access storage device through USB of the present invention can be realized. As shown in FIG. 2, the mapping table 17 is a reference for the logic memory structure 11 in the flash file system. The flash file system in accordance with a logic memory structure 11 includes a boot partition section 12, a file allocation table section 13, a root entry section 14, a file entry section 15, a database section 16. The flash controller 4 will decide which data is needed to be saves in a flash random access memory and determine the priority sequence of the access instruction according to the mapping table 17 in the flash file system.
FIG. 3 is a flow chart illustrating an embodiment of a method to access storage device through USB according to the present invention. The method includes the following steps:
- Step 21: connecting the USB device to the USB interface of a computer;
- Step 22: outputting the instructions to the flash controller by the computer;
- Step 23: deciding which data is needed to be saved in a flash random access memory and determining the priority order of the access instruction according to a mapping table of a flash file system by the flash controller, wherein the mapping table is a reference for the flash file system in accordance with a logic memory structure, and the flash file system in accordance with a logic memory structure including a boot partition section, a file allocation table section, a root entry section, a file entry section and a database section;
- Step 24: executing the access instructions according to the priority order by the flash controller and writing the data temporarily saved in the flash random access memory into the flash memory.
FIG. 4 is a flow chart illustrating another embodiment of a method to access storage device through universal serial bus according to the present invention. The method includes the following steps:
- Step 31: connecting the USB device to an USB interface of a computer;
- Step 32: outputting the instructions to a flash controller by the computer;
- Step 33: deciding whether the data is needed to be temporarily saved in the flash random access memory according to the mapping table of the flash file system so that if some of the data is needed to be temporarily saved in the file entry section or the file entry section, returning to Step 32, otherwise, proceeding to the next step;
- Step 34: deciding the priority order according to the flash file system by the flash memory, if the instruction has a priority, proceeding to the next step, otherwise, returning to Step 32;
- Step 35: executing the access instructions according to the priority order by the flash controller and writing the data temporarily saved in the flash random access memory into the flash memory.
According to the description above, it is clear that the method can be used to access storage devices via the USB. Because the data is not needed to be repeatedly moved into and from buffer and the priority order of the access instructions can be determined while controlling the data and the instruction access, the efficiency of accessing data can be improved by the method of the present invention. In the method of the present invention the frequency of moving data into and from the buffer can be decreased and the priority of the access instructions can be appropriately determined to optimize the efficiency of accessing the storage device.
While the present invention has been illustrated by the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be effected therein without departing from the spirit and scope of the present invention as defined by the appended claims.
Patent Application
20070283095
