OAM object tape support

The Object Access Method (OAM) is also an access method supporting a class of data referred to as objects. An object is a named stream of bytes. The content, format, and structure of that byte stream are unknown to OAM. There are no restrictions on the data in an object. For example, an object can be a compressed scanned image or coded data. Objects are different from data sets handled by existing access methods.

In an IBM® tape library environment, the SETOAM DATACLASS parameter can be specified using a data class that contains the media type or recording technology; these specifications are associated with an Object or Object Backup storage group in the CBROAMxx member of PARMLIB.

In a stand-alone environment, the SETOAM TAPEUNITNAME parameter can be specified using an esoteric that contains 3592 Model J devices. These specifications are associated with an Object or Object Backup storage group in the CBROAMxx member of PARMLIB.

In addition, the SETOAM DATACLASS parameter can also be used inside and outside an IBM tape library environment to take advantage of performance scaling. Performance scaling is only available with MEDIA5 (300GB) tape cartridge media. A DATACLASS with the performance scaling data class attribute selected can be specified for OBJECT storage groups to improve the random retrieval rate of primary objects; whereas, objects written to OBJECT BACKUP storage groups can specify a DATACLASS that does not specify performance scaling and can continue to utilize the full capacity of the MEDIA5 volume.

In addition to the performance scaling option available with the 300GB MEDIA5 cartridge, the 60GB MEDIA7 economy cartridge can also be used to improve the random retrieval rate of primary objects.

Recommendations:

To use the volumes effectively, we recommend that you run in 3590-1 emulation mode, otherwise with 3490E emulation, OAM will run out of 22-bit tape blockids before being able to fill the tape.
Note: The 3592 Model J does not support 3490E emulation mode with MEDIA6, MEDIA7, or MEDIA8 tape cartridge media.
To guarantee that objects written on any drive in the esoteric group can be read on any drive in the same esoteric group, specify esoteric unit names with compatible recording technologies.
In order to prevent allocating an inappropriate drive for a request, it is important to segregate, in an esoteric or a generic, the 3592 Model J devices with the upgraded microcode support for MEDIA6, MEDIA7, and MEDIA8 from any other 3592 devices without the upgrade. Another alternative is to consider upgrading all 3592 drives.
Storage groups using 3592 Model J drives should be comprised of either WORM tape volumes or rewritable tape volumes. In addition, you should consider the separation of standard length and economy length media types.
In the system-managed tape library environment (automated or manual), the SETOAM DATACLASS parameter at the storage group, or global level, can be used to request a specific media type through the data class media interchange specification. Outside of the system-managed type library environment, the tape management system pooling support can be used to direct the storage group request to a particular set of media with a new option to now append the storage group name to the OAM object tape data set names.

Table 1 shows the entry for the optical configuration database (OCDB) MEDIATYP field. The media type is defined in the MEDIATYP field. These media types are defined:

MEDIATYP field is 07, meaning Enterprise Tape Cartridge. When utilizing the tape to its full capacity, the CAPACITY value for the media is 292 968 448 kilobytes and if utilizing the media to its performance scaled capacity, the CAPACITY value for the media is 60 653 568 kilobytes.
MEDIATYP field is 08, meaning Enterprise WORM Tape Cartridge. When utilizing the tape to its full capacity, the CAPACITY value for the media is 292 968 448 kilobytes with the description of "Represents the approximate number of kilobytes of data for an IBM 3592 Enterprise WORM Tape Cartridge. This value will be returned from the drive (3592 Model J) and is used here as an approximation that will be close to actual value."
MEDIATYP field is 09, meaning Enterprise Economy Tape Cartridge. When utilizing the tape to its full capacity, the CAPACITY value for the media is 60 653 568 kilobytes with the description of "Represents the approximate number of kilobytes of data for an IBM 3592 Enterprise Economy Tape Cartridge. This value will be returned from the drive (3592 Model J) and is used here as an approximation that will be close to actual value."
MEDIATYP field is 10, meaning Enterprise Economy WORM Tape Cartridge. When utilizing the tape to its full capacity, the CAPACITY value for the media is 60 653 568 kilobytes with the description of "Represents the approximate number of kilobytes of data for an IBM 3592 Enterprise Economy WORM Tape Cartridge. This value will be returned from the drive (3592 Model J) and is used here as an approximation that will be close to actual value."

Table 1. Library table column descriptions
Column description	Name	DB2 type	DB2 attribute	Report label
Capacity of tape	CAPACITY	INTEGER	Not Null	CAPACITY
Media Type	MEDIATYP	CHAR(2)	Not Null	MEDIATYPE