The Removable Cartridge Devices are a product which allows you to manage, store and retrieve removable media. The removable media is a cartridge, which might be a tape cartridge or a removable magnetic disk. Removable cartridge devices can be used in either ways by making use of a wide range of robotic library devices or by means of a human operator. Removable cartridge devices will support a wide range of library devices, and facilities to make it easy for SGI to add support for additional robotic devices.

Removable cartridge devices should not provide end user application functionality, nor should it be involved in data I/O operations to cartridges. The removable cartridge devices can be used for Direct Device Access which means that the user reads and writes cartridges directly, using a utility program such as tar or dd.

The removable cartridge devices can also be used for Backup which is characterized by frequent, automatic writes of user files and infrequent, user-requested reads of data from the tertiary medium. It can also be used to archive of data which can be used typically be invoked manually by the user or by both writing information to the tertiary storage medium and for retrieving data from the tertiary store.

The removable cartridge devices is provided by the Hierarchical Storage Management, which is traditionally characterized by automatic movement of data between tertiary storage and disk-based file systems. The removable cartridge devices can be used for user files which have not been moved to the tertiary medium without the user's knowledge; when the user accesses a file which has been moved from disk, the user experiences a delay while the file is retrieved from tertiary storage and restored to disk removable cartridge devices is designed to be completely independent of user applications, it could also be used to manage library units for which computer can access to data. An example of such a device would be a broadcast video library unit equipped only with videotape units, such as an Ode tics Broadcast Library.

Removable cartridge devices could be used to keep track of all of the videotapes at the site, whether inside a library or not, and it would control one or more robotic library units. Using custom application software and signaling protocols specified by the videotape deck manufacturers, the SGI systems could perform standard control operations on the videotape machines. The removable cartridge devices can be used to solve the problems of implementing two standard interfaces, one for applications which can be used cartridges and one for robotic library units which store and retrieve cartridges.

Removable cartridge devices implement a set of core functions which allow client applications to allocate, de-allocate, mount, and un-mount cartridges to the actual library storage device. The applications may have its own essentially naming scheme for cartridges. The removable cartridge devices use library storage systems, which is used for both robotic and non-robotic systems. Removable cartridge devices are designed to make easy to implement new libraries by providing sufficient richness to handle large and complex library units. A number of Administrative Interfaces are used to communicate between a number of command-line and graphical-interface administration systems which are included as a part of removable cartridge devices.

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