The DB2 database management system operates as a formal subsystem of the OS/390 and z/OS operating system. DB2 processes can be executed in several different address space regions within OS/390 and z/OS, such as IMS or CICS.
The address spaces used in the operation of DB2 include:
System Services Address Space (SSAS)
Database Services Address Space (DSAS)
Internal Resource Lock Manager (IRLM)
Distributed Database Facility (DDF)
Stored Procedure Address Space (SPAS)
Allied Address Spaces
Figure 2.1 shows the relationship between the address spaces used by DB2.
Each DB2 subsystem will have its own IRLM. ...