In noncompatibility mode PCF and ICSF can run simultaneously and independently. You can run both ICSF and PCF at the same time. Just start one and then the other. Both ICSF and PCF run completely separate from each other. Each has its own applications and each uses its own services and CKDS.

You cannot run a PCF application on ICSF, even if you reassemble it. If you run an application on ICSF that calls a PCF macro, the application ends abnormally, because ICSF does not support the PCF macros in noncompatibility mode.

Because each product runs separately, neither product loses any function in exchange for compatibility. When ICSF is in compatibility or coexistence mode, you can no longer change the master key dynamically. In noncompatibility mode, this function is still possible. Therefore, except for when your installation is migrating to ICSF, you probably want to run ICSF in noncompatibility mode.