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FMS Architecture

A general scheme of the architecture of an FMS is depicted in fig. 13

Figure 13: A scheme of a generic File Management System architecture

The file system provides a unified data structure containing the data along with the necessary management information for the use of the FMS.

The user application ``sees'' and/or internally organizes the files according to a certain logical scheme (pile, sequential, ...).

A logical I/O module provides the necessary translation from this logical data organization into a physical one, suited for the low-level storage management subsystem. Record management is performed at this level, in the sense that it maps a physical (vlock-oriented) data structure into and from a record-oriented one, which is organized into some logical scheme at the upper level.

The I/O supervisor is responsible for I/O initialization, termination and data validity through multiple accesses. It also provides device independance, managing the communication between so to offer to the upper layers a uniform service structure across the various possible storage I/O devices managed by the disk (tape, cdrom, ...) I/O subsystem.

Franco Callari