HANDLING OF DATA STORAGE WITHIN A FLASH MEDIA DEVICE
A flash memory device can be subdivided into smaller areas (called chunks) that can written independently over a extended periods of time even though each sector must be erased as a single unit. It may be determined which chunks of data within a sector are valid or invalid and the valid data can be recovered. When errors are detected, the retrieved data may be retrieved from an earlier stored memory chunk in another sector. The type of data stored within a chunk is flagged within that chunk. Each chunk can be date and/or time stamped. Each chunk can also be given a unique, but increasing, sequence number. These values can be used to determine the latest chunk of a particular type.
1 . A method of storing and retrieving data within a memory device, the method comprises:
allocating at least one memory sector for each data type to be stored within the memory device;
dividing each memory sector into a plurality of memory chunks;
erasing all memory locations within each memory chunks;
dividing data of the data type into a plurality of data blocks corresponding to the size of the memory chunks;
storing the data blocks into the corresponding newest memory chunks;
retrieving the data blocks from the corresponding memory chunks;
detecting data errors within the data blocks retrieved from the memory device;
if data errors are detected in a retrieved data blocks, retrieve the data block from a next oldest sector of the data type corresponding to the memory chunk in the newest memory chunk having an error; and
returning to a user data of the data type containing data blocks retrieved without an error.
2 . The method according to claim 1 , wherein the method further comprising:
if no data errors are detected in the retrieved data blocks, returning to a user data of the data type containing data blocks retrieved without an error.
3 . The method according to claim 1 , wherein the detecting an error is performed using a CRC checksum.
4 . The method according to claim 1 , wherein the detecting an error is detecting an incorrect erased memory block pattern.
5 . The method according to claim 1 , wherein the memory device corresponds to a flash media device.
6 . The method according to claim 1 , wherein the data blocks stored within the memory chunks comprises a data chunk header and data.
7 . The method according to claim 6 , wherein the data chunk header comprises a date field, a time field, a sequence number field, a data type flag field, and a CRC checksum field.
8 . A computer-readable storage medium containing encoded data corresponding to computer readable instructions for a programmable computer system for implementing a method of storing and retrieving data within a memory device, the method comprises:
allocating at least one memory sector for each data type to be stored within the memory device;
dividing each memory sector into a plurality of memory chunks;
erasing all memory locations within each memory chunks;
dividing data of the data type into a plurality of data blocks corresponding to the size of the memory chunks;
storing the data blocks into the corresponding newest memory chunks;
retrieving the data blocks from the corresponding memory chunks;
detecting data errors within the data blocks retrieved from the memory device;
if data errors are detected in a retrieved data blocks, retrieve the data block from a next oldest sector of the data type corresponding to the memory chunk in the newest memory chunk having an error; and
returning to a user data of the data type containing data blocks retrieved without an error.
9 . The computer-readable storage medium according to claim 8 , wherein the method further comprising:
if no data errors are detected in the retrieved data blocks, returning to a user data of the data type containing data blocks retrieved without an error.
10 . The computer-readable storage medium according to claim 8 , wherein the detecting an error is performed using a CRC checksum.
11 . The computer-readable storage medium according to claim 8 , wherein the detecting an error is detecting an incorrect erased memory block pattern.
12 . The computer-readable storage medium according to claim 8 , wherein the memory device corresponds to a flash media device.
13 . The computer-readable storage medium according to claim 8 , wherein the data blocks stored within the memory chunks comprises a data chunk header and data.
14 . The computer-readable storage medium according to claim 13 , wherein the data chunk header comprises a date field, a time field, a sequence number field, a data type flag field, and a CRC checksum field.