Patent ID: 8539139

Claim:
A method comprising: counting a number of writes to a device (“D 1-n ”) consisting of n sub-devices (“D a ”): [ W 1 , 1 … W 1 , m - 1 W 1 , m W 2 , 1 … W 2 , m - 1 W 2 , m … … … … W n , 1 … W n , m - 1 W n , m ] where: W a,b is the number of writes to sub-device D a in time period “b”; n>1; m>1; for each sub-device D a : determining a write rate for sub-device D a at the end of time period p (“WR a,p ”) using the following equation: WR a , p = ∑ b = 1 p ⁢ W a , b ∑ b = 1 p ⁢ t b where: t b is the amount of time in time period “b”; p<m; controlling the write rate to sub-device D a in time periods after time period p so that device D 1-n will have a guaranteed lifetime (“LD 1-n ”).