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BVS - Tape and Cartridge Management System
detailed Informations
BVS is a tape and cartridge management system for VM and VSE. It consists of multiple components:

1. BVS Base
   for the management of all tape data sets read or written under VSE
   
   
2. BVS CICS Interface
   for online display and update of the BVS catalog
   
   
3. BVS/VM Feature for
   a) dynamic attach and detach of tape units
   b) administration of all tape data sets read or written in CMS
   c) online display and update of the BVS catalog by a CMS user
   
   
4. BVS Roboter Interface
   to allow usage of robot systems under BVS. BVS allows the initialization of robot cartridges and ensures an equal arbitration of units and medias. For vaulting, BVS passes the appropriate eject command to the robot system. Up to 4 different robot systems are supported simultaneously.
   
   
5. BVS/PC Feature
   to view and update the BVS catalog with an ordinary graphical interface - even without the host system running. This feature allows a paperless trail of the BVS catalog for audit purposes.
   
   

Data Security with BVS
BVS ensures that the proper data set is read and no unexpired data set will be overwritten. All data sets are recorded into a unique catalog when created. Data sets are protected by their expiration date and/orby the number of generations. There are no more uncontrolled data sets in the system.

All modifications to the BVS catalog are logged in a log data set to provide maximum security for the catalog.

BVS records data set and volume specific information in its catalog. For data sets, the data set name, the generation and version number, creation date and time, expiration date and the serial number of the volume holding the data set are retained. For each reel or cartridge, the data set on it, the vault identification and the density are stored.

All reels and cartridges may be freely used and are identified by their unique volume serial number (VOL1 label). No one can determine which data is stored on which medium.

Dynamic Operation of BVS
The fact, that a data set is opened, is sufficient for BVS to become active.

For input data sets, BVS usually looks for the latest generation of the data set specified in the label field of the TLBL statement. For output data sets, BVS looks for an expired reel mounted on any unit. If the required reel or cartridge is not found, the operator is requested to mount the appropriate reel. After a user defined time interval, BVS resumes the search for the reel.

As BVS does not need any manual specifications in its catalog, there is also a very flexible handling of multifiles, allowing the utilization of the maximum capacity of cartridges. There is no fixed or predefined sequence of multifiles.

Multifile processing
Multifile processing under BVS allows:

1. tape output data sets to be written sequentially. E. g., at the end of a job stream, all modified disk data sets may be backed up to one cartridge.
   
   
2. a tape file to be written to a cartridge which holds a certain "prime dataset" (= 1st dataset of a multi file volume). An output may be written daily to the same cartridge, allowing at the end of the month all data sets to be read from one single volume.
   
   
3. a tape output to a so called "Multi-File-Chain", which means grouping data sets simply by specifying a special VOLSER in the TLBL statement. This may be used to group different data sets created during a job stream onto one medium.
   
   
4. the tape output to be written to any free cartridge which is positioned at the end of the last multi-file on it. This is very useful for the operatorless night-shift as all cartridges are filled completely with data. This technique can even be set by a global BVS option, allowing all tape files to be written as multifiles without any changes to the JCL. (When reading such a dataset, only the label must be specified in the TLBL statement, since BVS recognizes on which volume the data set resides)
   
   

The latter procedure is also useful when using IBM 3590 tape units (Magstar) to make the best use of the high capacity of these cartridges.

Efficiency by BVS
When using BVS, manual actions are unnecessary. Maintaining index cards, sticking labels to reels and cartridges is a frequent source of errors and a reason to re-run jobs.

BVS allows the usage of tape and cartridge units in all partitions and on all virtual and real machines. Assignments, attaches and detaches are handled by BVS. Additionally, the units are only occupied between open and close during the actual reading or writing of a data set.

Tape files can be assigned to a disk without any program modifications. BVS allows the reblocking of data sets, either for one or for all data sets created in the system. The utilization of reels and cartridges can be optimized by the dynamic multifile processing.

Maintenance Functions in BVS
All information concerning data sets and volumes may be retrieved at any time from the central BVS catalog. There are batch programs and online inquiries and updates, either from CICS or VM/CMS. The operator can review the catalog from his VSE console.

Extensive Comfort in BVS
By specifications in the TLBL statement, it is possible to define rewind and unload options independently from the program.

BVS marks successfully read data sets by a so called 'process flag'. This allows a variable number of data sets to be read by one DTF in the program and one or multiple TLBL statements in the JCL. Depending on the number of generations to be read, BVS itself performs the necessary opens.

All assignments (ASSGN statements in VSE, attach and detach in VM) are automatically handled by BVS.

Rearranging of data sets for security reasons is supervised by BVS. All volumes removed from the EDP center receive a unique location number for fast and easy retrieval from the vault.

Scheduling systems can edit the BVS catalog for the volumes needed for the workload of the current day (interface for HS5000 APM is available). There is a read routine for user written programs to access the BVS catalog.

BVS allows classification of reels and volumes by the far left position of the volume serial number. Volumes belonging to a specified area (e.g., personnel office) may be handled differently from regular tapes.

Tape data sets may be written as DASD files without any program changes.

Robot System Support in BVS
BVS supports all robot systems currently available on the market. Up to 4 systems may be operated by BVS concurrently. By specifications, BVS must be informed only once which cartridges and which units are accessed by which robot system. This allows a specific support for each robot system. Additionally, BVS ensures a balanced utilization of units and cartridges to get balanced wear and tear.

Utilities in BVS
BVS has different utility programs. Initialization of cartridges results in an entry in the BVS catalog. Overwriting of protected volumes and assignment of duplicate volume serial numbers is avoided. When installing a robot system, the volumes of this system can be initialized automatically.

An I/O optimized tape file copy program is available, also allowing sequence files to be copied by specifying only one TLBL statement. Additionally, this program allows copying of data sets which hold tapemarks within its data (e.g., IDCAMS Backups).

Implementation of BVS
The concept of BVS allows most of the users to start processing under control of BVS with their existing job control. Prerequisites are only the unique labels in the TLBL statements and all the volumes to be initialized with unique volume serial numbers (VOL1).

If programs write unlabeled tape files, BVS offers the dynamic translation of these files to labeled files without any program changes.

Retention periods and desired number of generations may be set as options in BVS, avoiding any JCL changes. For existing tape data sets, BVS has an implementation program to include these data sets.

The conversion of existing tape management catalogs from other tape management systems is supported.

The unique BVS dynamics requires no predefinitions in the BVS catalog. Thus, the whole tape processing may be controlled by BVS immediately after installation.

System Integrity by BVS
BVS doesn't change any IBM phases. TLBL statements remain in the IBM format. The BVS catalog may be used by user applications or other software, since an appropriate read routine is available in BVS.

Maintenance and Development of BVS
BVS is developed and maintained in Germany. All documentation is available in German and English language.

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