Patent ID: 6715027
Filing Date: 2004-03-30
Classification: G06F

Abstract:
A method for ranked cleaning using a flash memory used in a file system, the method comprising the steps of:a) calculating rank values for all segments of the flash memory periodically; and b) if the storable space of the flash memory becomes less than a predetermined volume, a cleaner operating to clean invalid space of segments in order of their rank values obtained in the previous step high to low and thus to secure new storage space, wherein the rank values are calculated by an equation expressed as: R=A&it;age&CenterDot;i2&it;v&CenterDot;fwhere v is the ratio of valid blocks to the entire segment, f is the ratio of free blocks in a segment, i is the ratio of invalid blocks, age is the time that has passed since the segment is cleaned, and A is the weight.