Transient errors and rollback recovery in LZ compression

This paper analyzes the data integrity of one of the most widely used lossless data compression techniques, Lempel-Ziv (LZ) compression. In this algorithm, because the data reconstruction from compressed codewords relies on previously decoded results, a transient error during compression may propagate to the decoder and cause a significant corruption in the reconstructed data. To recover the system from transient faults, we designed two rollback error recovery schemes for the LZ compression hardware, the "reload-retry" and "direct-retry" schemes. Statistical analyses show that the "reload-retry" scheme can recover the LZ compression process from transient faults in one dictionary reload cycle with a small amount of hardware redundancy. The "direct-retry" scheme can recover normal operations with a shorter latency but with a small degradation in the compression ratio.