METHODS FOR MEASURING USABLE LIFESPAN AND REPLACING AN IN-SYSTEM PROGRAMMING CODE OF A MEMORY DEVICE, AND DATA STORAGE SYSEM USING THE SAME

摘要

A data storage system comprises a host and a flash memory device having a non-non-volatile memory. A controller of the flash memory device calculates an average erase count of the flash memory to obtaining a remaining period of time indicating usable lifespan of the flash memory device. The host obtains an index by comparing the average erase count with a first threshold and determines a performance capability status for the flash memory device. The performance capability status is set to a first status when the average erase count exceeds the first threshold. The host generates an indication based on the performance capability status and performs a limp function responsive to the first status. The limp function loads a predetermined in-system programming code for replacing an original one to configure a minimum number of at least some spare blocks of the flash memory reserved and used for data update operations.