Concurrent checkpointing for rollback recovery for system failures is disclosed. This amorphized region is then etched to the first depth. Each client receives the least significant bits. In other words, an inverse 2:3 pull-down process is controlled corresponding to the continuity of a pattern of a repeat field. After initially receiving the messages X1 to X3, the receiver may sleep, or it may receive announcement messages from another channel Y. To reduce the performance penalty of including a de-trapping operation, the programming cycle of a single series of increasing pulses alternating with verify operations is replaced with a cycle including a pulse from each of two or more staircases, where each staircase is for a corresponding subset of the data states.