Probabilistic graphical model for flash memory programming

Flash memory presents significant advantages over hard drives in terms of read speed and power efficiency; however its lifetime can be several orders of magnitude smaller. Thus increasing lifetime of flash memory via signal processing techniques is an important research area. The first half of the paper presents a statistical method for estimating the health of the cells in a Flash memory, based on which a variable error correction coding scheme can be used to increase lifetime. The second half of the paper proposes a statistical approach to increase lifetime when the flash controller can dynamically vary the program and erase operation strategy. This approach uses Markov Decision Processes (MDP) to choose the optimal program or erase strategy at any given point in the life of a Flash memory based on its current state or health. From a bigger picture stand-point, the paper presents a novel way of flash management using a Markov model for health of the memory at any given point in its lifetime.