ICKP: A consistent checkpointer for multicomputers. There has been much research on checkpointing algorithms for parallel and distributed systems; but surprisingly few implementations for uniprocessors, multiprocessors, and distributed systems, and none at all for multicomputers. We discuss ickp, our consistent checkpointer for the Intel iPSC/860, which is the first general-purpose checkpointer for a multicomputer. It is a checkpointing library that may be invoked asynchronously from the host processor, at a periodic interval, or by a library call. It implements three consistent checkpointing algorithms, two optimizations to reduce checkpoint time and overhead, and recovery.