Base Primitive Environment overview

The IMS Base Primitive Environment (BPE) is a common system service base upon which many other IMS components are built. BPE provides services such as tracing, message formatting, parsing, storage management, sub-dispatching, and serialization.

The following IMS components use BPE:

  • Common Queue Server (CQS)
  • IMS Connect
  • Open Database Manager (ODBM)
  • Operations Manager (OM)
  • Resource Manager (RM)
  • Repository Server (RS)
  • Structured Call Interface (SCI)

You can optionally have Database Recovery Control facility (DBRC) use BPE.

When an IMS component that uses BPE is started, the component loads a copy of the BPE service modules into its address space from the IMS program libraries. The IMS component's modules are specific to that component; however, the BPE service modules are common across the various address spaces. The base system service functions are therefore identical in every address space that uses BPE. The following figure shows the relationship of BPE, IMS components, and IMS program libraries.

Figure 1. BPE and IMS components
A cylinder represents IMS program libraries. Arrows show that data flows from the program libraries to four IMS components with BPE address spaces, represented as 4 boxes.

Most of the time, BPE is a hidden layer in an IMS component address space. However, you can use the following external interfaces to BPE:

Configuration
You can configure certain attributes about an address space that uses BPE at startup by using statements in BPE PROCLIB member data sets. For example, you can set the default level and size for BPE-managed trace tables. Information about defining BPE with the BPE PROCLIB member data set is in IMS Version 15.3 System Definition.
Commands
You can use the small set of commands that BPE provides to operate on BPE-managed resources. For example, you can display and change attributes of BPE-managed user exit routines and trace tables. Information about BPE commands is in IMS Version 15.3 Commands, Volume 3: IMS Component and z/OS® Commands.
User exit routines
You can customize the operation of an IMS component address space by writing user exit routines. Components running with BPE can use the BPE user exit routine service to call component-specific user-supplied exit routines. BPE also has user exit routines of its own. User exit routines that are called through BPE receive control with a standard BPE user exit routine interface and are allowed to use BPE user exit routine callable services. Information about BPE user exits is in IMS Version 15.3 Exit Routines.
Messages and Abends
BPE has its own messages and abend codes. IMS Version 15.3 Messages and Codes, Volume 4: IMS Component Codes includes information about BPE abend and service return codes and BPE messages.