Advanced Topics › TPCF Device Processing › Factors That Influence TPCF Preferencing

Factors That Influence TPCF Preferencing

TPCF does not replace the z/OS allocation process; TPCF interacts with z/OS allocation. The types of criteria TPCF uses to influence device selection (logic in the TPCEDLXT and TPCSRMXT exit routines and device status changes you make through the VARY command) are applied between steps in the z/OS allocation process.

TPCF is not the only program that influences device selection through preferencing. z/OS and other vendor software use preferencing. Final device selection is a combination of the preferencing applied by z/OS, TPCF, and other vendor software. Factors that influence or limit TPCF preferencing include:

• The contents of the z/OS eligible device list (EDL)
• The way z/OS allocation and other vendor software eliminate devices from eligibility for allocation
• The way z/OS allocation and other vendor software preference devices in the EDL