Abstract: The present invention includes aspects pertaining to enabling an IMS batch application program to temporarily release its access to IMS resources that it shares with an IMS database management system or other non-IMS system agent, without terminating the application program. The present invention identifies when the batch application program issues a call that generate a sync point, and disconnects the program's connection to the IMS resources. The batch application program retains access to any independently obtained non-IMS resources when the program is disconnected from the IMS resources. The IMS database management system or other non-IMS system agent has temporary exclusive access to the IMS resources after the batch application program connection is disconnected. After such temporary exclusive access is complete, the batch application program's connection to the IMS resources is reestablished, and the batch application receives a response to its original call that generated a sync point.

Abstract: A method, computer program product and system for archiving data from an operational database. Data to be archived from the operational database may be stored either as received or transformed in a manner that allows the transformed archived data to be retrieved bit-for-bit identical to the original input received. Further, the data stored in the archive storage is read-only meaning that the data cannot be updated, deleted or modified. Further, backup copies of each of the storage units, which store the archived data, in the archive storage are created for disaster recovery purposes. Additionally, hash values are computed for each of the storage units in the archive storage which are used to detect unauthorized changes to the data stored in the storage units. In this manner, the authenticity of the data stored in the archive storage may be substantially guaranteed.

Abstract: A method of ensuring that an IMS database and its description are synchronized. A copy of the description used to load the database is stored and maintained within said database. Before the database is accessed, a copy of the description is compared with another copy of the description stored in a data management block. A determination is then made as to whether the copy of the description in the database and the copy of the description in the data management block are synchronized. Responsive action, such as alerting the user to a problem with the description, may occur if the database descriptions are not synchronized.

Abstract: Space within an IMS database can be managed during loading or updating of the database. After an IMS database is loaded, a space management program can assume control from the IMS program for a period of time. During this period of time, the space management program obtains memory addresses of IMS control blocks built by the IMS program and further obtains information about the IMS database. When the IMS program attempts to insert data into the IMS database, either during loading or updating of the database, the space management program reassumes control from the IMS program. The space management program selects a storage location for the data to be stored, and modifies the IMS control blocks to indicate the storage location selected. The space management program may also insert the data into the storage locations selected. Control is then passed back to the IMS program.

Abstract: An index can be maintained during a reorganization of data in a database by retaining each root segment, or the prefix component of each root segment, in its storage location during the reorganization. Correction of an index after a reorganization of data in a database can be facilitated by assigning a unique token to each target segment, or the prefix component of each target segment, and each corresponding index entry having an address to a target segment, prior to a reorganization of data. The unique token for a given target segment, or the prefix component for a given target segment, and the unique token for a corresponding index entry are the same. After a reorganization of data in the database, the unique token of a first index entry is read. Then, the unique token of each target segment, or the prefix component of each target segment, is read until a match is found.

Abstract: A system and methods for rapid unloading and reorganization of hierarchical databases. Overflow and a window of blocks are progressively read into memory. Unloading proceeds as the scan cylinders window moves ahead. The reading of blocks stays about scan cylinders ahead of the unload. As a segment is unloaded, its space is converted to free IMS space and when appropriate, combined with adjacent free space already in the block. Thus about a window behind the unload point in the database, all of the segments in a block will have been converted to free space making the block one unit of free space.

Abstract: A system and methods for rapid unloading and reorganization of heirarchical databases. Overflow and a window of blocks are progressively read into memory. Unloading proceeds as the scan cylinders window moves ahead. The reading of blocks stays about scan cylinders ahead of the unload. As a segment is unloaded, its space is converted to free IMS space and when appropriate, combined with adjacent free space already in the block. Thus about a window behind the unload point in the database, all of the segments in a block will have been converted to free space making the block one unit of free space.

Abstract: Space within an IMS database can be managed during loading or updating of the database. After an IMS database is loaded, a space management program can assume control from the IMS program for a period of time. During this period of time, the space management program obtains memory addresses of IMS control blocks built by the IMS program and further obtains information about the IMS database. When the IMS program attempts to insert data into the IMS database, either during loading or updating of the database, the space management program reassumes control from the IMS program. The space management program selects a storage location for the data to be stored, and modifies the IMS control blocks to indicate the storage location selected. The space management program may also insert the data into the storage locations selected. Control is then passed back to the IMS program.