Multi-disc optical data storage system for use with a host computer for emulating a magnetic disc device

A multi-disk optical data storage and emulation system for use with an operatively associated host computer system to emulate a magnetic disk device, the data storage and emulation system comprising:

• a plurality of optical disks accommodated in the system, each of the plurality of optical disks being sized according to one volume of the magnetic disk device, said plurality of optical disks representing a plurality of volumes of magnetic disks;
• a plurality of optical disk drive units fewer in number than said plurality of volumes of magnetic disks, each of the plurality of optical disk drive units receiving a one of the plurality of optical disks and communicating data therewith;
• transport means, operatively connecting said plurality of optical disks with said plurality of optical disk drive units, for selectively transporting first ones of the plurality of optical disks to first ones of the plurality of optical disk drive units to enable access to the first ones of optical disks by the first ones of optical disk drive units;
• control means connected to said transport means for controlling the transport and access of a first optical disk assigned to a specific first magnetic disk volume in accordance with an access command for access to the magnetic disk device received from the operatively associated host computer system in relation to the specific first magnetic disk volume, the control means including a data processor external of said host computer and having i) a first processing portion interpreting said access command and ii) a second processing portion executing said interpreted access command to selectively load said first optical disk into a one of said plurality of optical disk drive units;
• and,
• a host computer system interface means, interfacing the operatively associated host computer system with the multi-disk optical data storage and emulation system to emulate the magnetic disk device, for emulating accesses to the plurality of optical disks as accesses to the magnetic disk device.

A data storage system comprising:

• a host system for receiving a command in a magnetic disk format, transmitting a command in the magnetic disk format, receiving data in the magnetic disk format, and transmitting data in the magnetic disk format;
• a magnetic disk storing data in the magnetic disk format;
• magnetic disk control means, connected to the magnetic disk, for accessing the magnetic disk and transferring the data stored in the magnetic disk to the host system in accordance with a command issued from the host system;
• a set of optical disks, each having a memory capacity equivalent to magnetic disk volume;
• conversion means, operatively connecting the data storage system to the host system, for converting said command in the magnetic disk format and data in the magnetic disk format into an optical disk format for ready use by the set of optical disks;
• optical disk control means for receiving from the host system a first command in the magnetic disk format and converting the first command into a first command in the optical disk format for ready use by the set of optical disks through the conversion means, thereby accessing the optical disks, converting the data stored in the optical disks into that of the magnetic disk format for use by the magnetic disk by the conversion means, and transferring the data to the host system, the optical disk control means including a data processor external of said host system and having i) a first processing portion interpreting said first command from the host system and ii) a second processing portion executing said interpreted first command to selectively generate a first optical disk load command signal;
• and,
• transport control means operatively connecting the set of optical disks to the optical disk control means, for transporting a one of the set of optical disks to a position accessible by the optical disk control means on the basis of said first optical disk load command signal from said second processing portion of the data processor.

A data storage system comprising:

• a host system for transmitting and receiving i) a command developed for use in a magnetic disk and ii) data of a variable-length format;
• a first memory medium storing data of a capacity corresponding to at least one unit of a magnetic disk volume in a fixed-length format;
• a driving unit, connected to the first memory medium, for reading and writing data from and to said first memory medium;
• memory means for storing first information indicating a corresponding relationship between the magnetic disk volume and said first memory medium, and storing second information indicating a use condition of said driving unit;
• buffer means for storing data of a predetermined track unit determined for the magnetic disk;
• and
• a control device, connecting the memory means, the buffer means and the driving unit to the host system, for interpreting the command for use for the magnetic disk received from said host system to assign said driving unit by making reference to the said information stored in said memory means, identifying a memory medium of said first memory medium and an access position of the memory medium corresponding to an access range requested by said host system by making reference to the first information stored in said memory means, controlling the assigned driving unit to execute a processing designated by the command for use for the magnetic disk with respect to the access position of the identified memory medium, and performing a format conversion with respect to data stored in said buffer means,
• wherein said control device includes i) means for transmitting and receiving data in the variable-length format to and from said host system, and transmitting and receiving data in the fixed-length format to and from said assigned driving unit and ii) a data processor external of said host system having a first processing portion interpreting said command received from said host system and a second processing portion for selectively accessing said identified memory medium of the first memory medium according to said command interpreted by the first processing portion.