Wrap-around sequence numbers for recovering from power-fall in non-volatile memory

摘要

Incrementing sequence numbers in the metadata of non-volatile memory is used in the event of a resume from power fail to determine which data in the memory is current and valid, and which data is not. To reduce the amount of metadata space consumed by these sequence numbers, the numbers are permitted to be small enough to wrap around when the maximum value is reached. Two different techniques are disclosed to keep this wrap around condition from causing ambiguity in the relative values of the sequence numbers.