Patent ID: 8200914
Filing Date: 2012-06-12
Classification: G06F

Abstract:
1. A firmware program product comprising a tangible storage medium having a processor readable program, wherein the processor readable program when executed by a processor causes the processor to: receive an atomic read-before-write instruction comprising new data, a target address for the new data, and an undo log address; read old data from the target address from a first storage device of a plurality of separate storage devices in communication over a storage communications channel with a controller comprising the processor; write the old data and the target address to a buffer of the controller; write the old data and the target address to the undo log address in a second storage device; write the new data to the target address in the first storage device; increment the undo log address with a value equivalent to a number of bytes comprising the old data, the target address, and a time stamp; receive an atomic undo instruction; read the old data and the target address from the undo log on the second storage device in response to the atomic undo instruction; and write the old data to the target address on the first storage device in response to the atomic undo instruction.