Chapter 5. Storage management 109
5.3.1  OAM components and SMS terminology
In this section, we describe the three components of OAM and also OAM terminology.
OAM components
OAM functions are performed by three components:
/SM590000Object Storage and Retrieval (OSR) component
This component provides an API for OAM. All OAM API functions are requested through 
the OSREQ assembler macro. Applications use this interface to store, retrieve, query, and 
delete objects, and to change information about objects. OSR stores the objects in the 
storage hierarchy and maintains the information about these objects in DB2 databases. 
OSR functions that start through the API require the OAM Thread Isolation Support (OTIS) 
application for administrative processing.
/SM590000Library Control System (LCS) component
This component writes and reads objects on tape and optical disk storage. It also 
manipulates the volumes on which the objects are stored. The LCS component controls 
the usage of optical hardware resources that are attached to the system.
/SM590000OAM Storage Management Component (OSMC)
This component determines where to store objects in the OAM storage hierarchy. It 
manages object movement within the object storage hierarchy and manages expiration 
attributes that are based on the installation storage management policy that is defined 
through the storage management subsystem (SMS). OSMC also creates the requested 
backup copies of the objects and provides object and volume recovery functions.
SMS terminology
To provide a better understanding of OAM, we explain SMS terms in the following sections.
SMS storage class
A storage class is a collection of performance goals and availability and accessibility 
requirements that are defined to SMS. It is used to select a device to meet those goals and 
requirements. 
Usually, three storage classes are set up for OAM where the storage administrator sets the 
names of the storage classes based on the naming convention in the enterprise. The three 
OAM storage classes to set up are listed:
/SM590000OAMDASD: Objects are stored in a DB2 table on fast magnetic disk.
/SM590000OAMTAPE: Objects are stored on magnetic tape, including tape robots.
/SM590000OAMOPTIC: Objects are stored on a 3995 optical device.
SMS storage group
An SMS storage group is a collection of storage volumes and attributes that are defined by 
the installation. Storage groups, with storage classes, help reduce the requirement for users 
to understand the physical characteristics of the storage devices that contain their data.
Note: The Content Manager OnDemand cache storage on a hierarchical file system (HFS) 
is not part of these SMS constructs.