A erful mechanisms for handling failures and manipulating persistent data. Unfortunately, standard recoverable memories incur an overhead of several milliseconds per transaction. This paper presents a system that improves transaction overhead by a factor of 2000 for working sets that fit in main memory. Of this factor of 2000, a factor of 20 is due to the Rio file cache, which absorbs synchronous writes to disk without losing data during system crashes. The remaining factor of 100 is due to vista, a 720-line, recoverable-memory library tailored for Rio. vista lowers transaction overhead to 5 psec by using no redo log, no system calls, and only one memory-to-memory copy: This drastic reduction in overhead leads to a overall speedup of 150-556x for benchmarks based on TPC-B and TPC-C.