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 E05. In addition to this, the SETOAM DATACLASS parameter can be used to indicate that the lower recording format (EFMT1) should be used by the drive, otherwise the default recording format (EFMT2) is used when writing from load point. 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 and performance segmentation. Performance scaling and performance segmentation are only available with MEDIA5 or MEDIA9 tape cartridge media. A DATACLASS with the performance scaling or performance segmentation data class attribute selected can be specified for OBJECT storage groups. The performance scaling data class attribute can be used 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 or MEDIA9 volume. For more detail on performance scaling and performance segmentation, see Performance scaling and segmentation for 3592.

In addition to the performance scaling option available with MEDIA5 and MEDIA9 cartridge, the 60GB MEDIA7 economy cartridge can also be used to improve the random retrieval rate of primary objects.

For the 3592 Model E05 (always in 3590 emulation mode), OAM derives the media type and capacity from the control unit. If EFMT2 recording technology is used to write on the volume (either by default or specifically requested), the MEDIA5 and MEDIA6 capacity is 488281088 KB. The MEDIA7 and MEDIA8 economy capacity is 97655808 KB. The MEDIA9 and MEDIA10 extended capacity is 700 GB.

The ERDS Physical ID (EPI) value for the 3592 Model E05 drive is a hex '12' and is stored in the DB2 TAPEVOL table of the OAM Optical Configuration Database (OCDB) for a volume written in either EFMT1 or EFMT2 by a 3592 Model E05 drive and displayed, as appropriate, in the volume display. In the standalone environment, drives must be put in their own unique esoteric to ensure that a volume written with EFMT2 recording technology is not inadvertently allocated to a drive that does not support EFMT2. For an IBM tape library, the SETOAM DATACLASS parameter at the storage group (or global level) can be used to specify a desired recording technology and ensure allocation to an appropriate drive.

Storage groups using 3592 Model E05 drives should be comprised of either WORM tape volumes or rewritable tape volumes. In addition, you should consider the separation of extended length, standard length and economy length media types. In an IBM tape library environment, the SETOAM DATACLASS parameter at the storage group (or global level) can be used to specify a desired media type. By specifying a DATACLASS media interchange for the storage group, MEDIA5, MEDIA6, MEDIA7, MEDIA8, MEDIA9 and MEDIA10 can be separated and prevent unintentionally writing on the wrong media type.

To assist the tape management system in mounting an appropriate media type in the stand-alone environment (non system-managed tape environment), the DSNWITHSGNAME global keyword on the SETOAM statement in the CBROAMxx PARMLIB member appends the object storage group name to the OAM data set names. For more information, please refer to Object tape data set low-level qualifier enhancement.