Abstract: One or more mapping data structures are maintained containing mappings of logical flash memory addresses to physical flash memory addresses. Each mapping data structure has a predetermined capacity of mappings. A master data structure is also maintained containing a pointer to each of the one or more mapping data structures. Additional mapping data structures are allocated as needed to provide capacity for additional mappings. Each time a mapping data structure is allocated or de-allocated the pointers in the master data structure are changed accordingly.

Abstract: A flash driver tracks data stored in a flash memory device through the use of logical-to-physical sector mapping. The mapping is stored in a data structure and allows data to be written into the next free physical sector in the flash memory medium. Write operations complete quickly, because there is no need to perform an erase operation in order to write new data on to the flash memory medium. Data loss due to power interruption during a write operation is also minimized by the described implementations. The logical-to-physical sector mapping stored in data structure is backed-up on the flash memory medium. In the event there is a catastrophic power interruption, logical-to-physical sector mapping can easily be reestablished by scanning the backed-up mapping in the flash memory medium. The backed-up information can be stored in a spare portion of a NAND or NOR flash memory medium.

Abstract: Erase operations are performed on a flash memory device by monitoring the entropic nature of the flash memory device. In one implementation, flash abstraction logic, tracks how many physical sectors are free to receive data; track how many physical sectors contain data that is dirty, and compare whether the physical sectors that are free to receive data outnumber the physical sectors that contain data that is dirty. A compactor performs an erase operation of one or more blocks when the physical sectors that contain data that is dirty outnumber the physical sectors that are free to receive data. In another implementation, the flash abstraction logic tracks how many physical sector addresses are free to receive data, and track when the physical sector addresses that are free to receive data are insufficient in quantity to receive write requests from a file system.

Abstract: An open-architecture transactional file system is described. In one described implementation, a file system comprises a plurality of interchangeable and/or customizable logic layers configured to manage operations on behalf of an application when the application makes data requests to a data source. Functionality associated with the file system is augmentable by substituting and/or modifying one or more of the plurality of interchangeable and/or customizable logic layers, respectively, enabling the file system to function with many different types of data sources.