APPARATUS FOR HEIGHTENING UTILITY OF SINGLE WRITING/MULTIPLE READING MEMORY MEDIUM

摘要

A system for Write Once Read Many (WORM) optical storage devices to appear rewritable used magnetic disk storage and optical WORM storage subsystem. All new write operations are made to a magnetic cache storage (28) which resides on the magnetic disk subsystem. A Least Recently Written (LRW) technique is used to determine which valid data in cache storage is the oldest, and this is transferred to the WORM storage (30) when room for new data is required. In this manner all new write operations are performed to the magnetic cache storage and only the oldest valid data is transferred to WORM storage optimizing its use.