IMS in the Parallel Sysplex Volume I: Reviewing the IMSplex Technology

80 IMS in the Parallel Sysplex, Volume I: Reviewing the IMSplex Technology

4.1.5 An OSAM cache modification example

To illustrate how OSAM buffer caching operates, we lay out the flow of a read and modify of

an OSAM block with two IMS data sharing subsystems expressing interest in the data.

Figure 4-2 is the first diagram to demonstrate how the OSAM CF structure operates with IMS

data sharing partners accessing OSAM databases.

Figure 4-2 OSAM cache read and update data: diagram 1

The OSAM block has been read into IMSA private buffer pool and the CF OSAM structure

directory entry has been updated to indicate that IMSA has interest in block G.