Abstract: A nonvolatile memory system for a host computer system including a nonvolatile memory and a volatile random access memory that is chosen because of its short access time. When main power to the host system and RAMDISK is interrupted, data stored in the volatile memory is automatically transferred to the nonvolatile memory where it is stored until power is restored. When main power is restored, the data is automatically returned to the volatile memory. The RAMDISK memory features a power monitoring circuit that detects when main power is interrupted and switches the system onto a battery backup power source in order to power the RAMDISK while data transfer takes place. After power has been restored, the backup battery is recharged automatically by the monitoring circuit.