A 30 terabyte mass storage architecture

A description is given of a system that contains the online storage of approximately 15 million patents or 30 Tbytes of data. Magnetic disk storage is used on an IBM plug-compatible mainframe to store the indices. Optical storage which offers the best cost/performance ratio, is used to store the images of the patents. Two types of optical storage devices are used: the removable optical disk and the jukebox. Removable optical disks have a relatively fast access time and therefore they are used to store the most frequently accessed patents. The jukeboxes have a relatively slow access time and are used to store the remainder of the patents. Both the removable optical disks and the jukeboxes are controlled by Unix supermicrocomputers such as the SUN-3. The intelligent controllers contain cache magnetic storage for matching the data transfer speed of the optical drives with the network. All of the removable optical disks and jukeboxes are connected together using packet-switching digital switches which offer an off-the-shelf IEEE 802.3 network with guaranteed end-to-end throughput.<>