This chapter examined most of the components that make up the DB2 environment. The operating systems for DB2 on a zSeries enterprise server are based on the core operating system of MVS. Within this structure, several address spaces make up the environment, and each address space is allocated certain functions. The main components of DB2 and all its managers are in the DBAS and SSAS. The IRLM communicates with DB2 and provides the internal lock manager.
Across the environment are security services, as a total umbrella to provide many levels of security. The highest level is the component called Security Server, which houses RACF.
DB2I and SPUFI are only two of several interfaces to DB2 but provide most of the direct interface to DB2 for DBAs and developers. SPUFI is used as a method of submitting batches of SQL statements, and DB2I as a real-time interface.
The installation process, performed from TSO or the msys for Setup DB2 Customization Center, is focused primarily on picking options for the many DSNZPARMs, the configuration parameters for DB2. More than 123 parameters can be modified online, without taking an outage.
The DB2 environment has six categories of commands and many utilities. The DSN commands and the DB2 commands are used the most.
The DB2 catalog and directory comprise the control repository for the environment. There are a large number of catalog tables, populated primarily by SQL DDL and DCL, for every object creation and modification.
We briefly examined the distributed networks architecture of SNA and TCP/IP and looked at how DRDA provides the services on top of those layers. Other subsystems objects, such as the buffer pools, the EDM pool, the RID pool, and the Sort pool, were discussed in terms of how DB2 uses them. These objects will be revisited in Chapter 17.