Flip-N-Write: A Simple Deterministic Technique to Improve PRAM Write Performance, Energy and Endurance

The Phase-Change Random Access Memory (PRAM) technology is fast maturing to production levels. Main advantages of PRAM are non-volatility, byte addressability, in-place programmability, low-power operation, and higher write en-durance than that of current flash memories. However, the relatively low write bandwidth and the less-than-desirable write endurance of PRAM remain room for improvement. This paper proposes and evaluates Flip-N-Write, a simple microarchitectural technique to replace a PRAM write operation with a more efficient read-modify-write operation. On a write, after quick bit-by-bit inspection of the original data word and the new data word, Flip-N-Write writes either the new data word or the "Flipped" value of it.