High-Performance Embedded Computing

4.4 Operating System Design 257

wear leveling Because flash memory wears out much more quickly with writes than other

types of permanent storage, flash memory systems use wear-leveling tech-

niques to maximize the lifetime of the flash memory. Wear-leveling methods

distribute writes around the memory to avoid using one block excessively. How-

ever, one Achilles heel of flash-based memory systems is the file allocation

table. Whenever a file is created, destroyed, or changed in size, the file alloca-

tion table must be updated. The file allocation table can therefore wear out much

more quickly than the remainder of the flash memory. This is one reason ...