Designing floating codes for expected performance

Floating codes are codes designed to store multiple values in a Write Asymmetric Memory, with applications to flash memory. In this model, a memory consists of a block of n cells, with each cell in one of q states {0,1,...,q - 1}. The cells are used to represent k variable values from an -ary alphabet. Cells can move from lower values to higher values easily, but moving any cell from a higher value to a lower value requires first resetting the entire block to an all 0 state. Reset operations are to be avoided; generally a block can only experience a large but finite number of resets before wearing out entirely. A code here corresponds to mapping from cell states to variable values, and a transition function that gives how to rewrite cell states when a variable is changed. Previous work has focused on developing codes that maximize the worst-case number of variable changes, or equivalently cell rewrites, that can be experienced before resetting. In this paper, we introduce the problem o...

• Type: Journal
• Year: 2010
• Where: TIT
• Authors: Flavio Chierichetti, Hilary Finucane, Zhenming Liu, Michael Mitzenmacher
• Keywords: Cell, Education, Lower Value, TIT 2010, Variable Changes