Object access

You can use the Initial Access Response Seconds (IARS) field to specify the desired response time (in seconds) required for locating, mounting, and preparing a piece of media for data transfer. OAM uses this value to interpret the storage level, that is, to place an object at an appropriate level in the object storage hierarchy. For objects, the IARS, OAM Sublevel (OSL), and sustained data rate (SDR) are applicable.

OAM uses IARS as follows:

If the IARS value is 0, OAM writes to either a DB2 table or a file system, depending on the OSL value, as described in Planning storage groups for OAM object collections.
If the IART value is 1-9999, OAM selects removable media, either optical or tape. If the SDR is greater than or equal to 3, the primary copy of the object is stored on a tape volume. If the SDR for the object is less than 3, the primary copy of the object is stored on an optical disk volume.

The IARS for an optical volume depends on its location. The time required for an operator to mount a shelf-resident optical volume is significantly longer than that for the automatic mounting of a library-resident optical volume. You can use up to four characters to specify a valid value of 0-9999, or leave the field blank. The default is blank and selects fixed DASD. However, an OAM request fails if it tries to use a storage class with a blank IARS value.