High performance pure block device designed and tested to handle unexpected resets cleanly. Can be used for driver on all NOR, NAND and serial flash types.

The FTL is a layer which provides an abstraction over NAND or NOR flash memory pages. The FTL layer is located between user application (usually a filesystem) and flash device driver.

FTL sits on top of NAND memory and manages blocks erasing and physical pages in such a way, that it presents NAND memory to the outside world as a number of logical pages. User can write any logical page as many times as they want. They don’t need to care about the requirement of erasing blocks or writing pages one by one. Number of logical pages is always lower than the total number of physical pages, because some space is needed for internal FTL’s data.

SFFSN Flash File System NAND

FTL is designed to support all types of standard NAND flash.

NAND flash is a relatively new flash technology designed to store large amounts of non-volatile data at reduced cost. It is characterized by having storage that can only be written to if previously erased – these blocks erase quicker than on NOR flash but is still quite long. Other features that differentiate it from NOR flash are that it is often shipped with a number of bad-blocks and their reliability is much increased if all single bit errors are detected and fixed.

NAND memory is divided into physical blocks. Each block is divided into physical pages. Each physical page in a block can be written only once before entire block needs to be erased. Moreover, pages in a block must be written one by one, starting from the beginning of a block.

There are many different NAND flash devices available all with slightly different characteristics while retaining the same base properties. The system supports all known manufacturers devices including: Samsung, Renesas, Toshiba, Micron and ST Micro. Sample drivers are provided for Samsung, ST, and Micron devices.