NAME
    *Rsm.pm* -- record storage manager.

DESCRIPTION
    Module implements data store for records representing individual
    objects. Apart from the indexing structures realizing oids and basic
    information form the object level, records are treated as arrays of
    bytes the structure of which is known at the object level realized by
    *Osm.pm*.

    The record storage manager is based on the Berkeley DB (1.x) storage
    system providing access to various database formats; *Rsm.pm* uses hash
    data files. Records are stored as oid/value pairs where the values are
    packed in the sequences of bytes.

ARCHITECTURE
    Current version of the module provides a very simple record manager
    relying heavily on DB_File package. The module can be described thru the
    groups of routines serving as the interface to *Rsm.pm*.

    The first group of routines allows the manipulation of object
    identifiers. Free oids obtained by releasing the object from the
    database are stored in the list of free oids realized directly as
    key/value pairs.

    Object manager *Osm.pm* handles relationships between instances and
    class records (objects) in a similar manner as in early network and
    hierarchical database storage systems. Each class is realized as a list
    including all instances as well as the sub-class objects. The
    implementation of the relationships among class and instance objects
    follows the semantics of the object hierarchy (poset) comprising a
    database is described in [].

    The simple routines for storing and retrieving records (*rec_read*,
    *rec_write*) are provided. Next, the set of routines (*inx_create*,
    *inx_defined*, *inx_print*, *inx_drop*) are implemented to manipulate
    main-memory hash indexes based on a single class attribute. Finally, the
    set of procedures (*db_create*, *db_open*, *db_close*, *db_commit*,
    *db_clean*) for the manipulation of the database files are provided.

NOTES
    The module *Rsm.pm* is planned to be (should be:) rewritten in a
    stand-alone file-based record storage system. The features planned: the
    custom object address space tuned for storing larger text records,
    efficient object packing which allows selective access to record
    components, and grouping of instance objects by their classes.

COMMENTS
    This module is part of the *qios* programming environment.