ICFs are PUs in a CPC configured to run only CFCC code. The PUs are not shipped with a fixed function assignment, but are assigned during power-on reset (POR) or later non-disruptively by on demand offerings such as: CBU, CUoD, CIU, ON/OFF CoD.
Those offerings allow the customer to convert, in seconds, a non-characterizable PU in any PU personality type such as: CPU, ICF, IFL, zAAP, zIIP and SAP.
An ICF can reduce the cost of exploiting coupling facility technology because:
- ICFs are less expensive than CPs.
- An ICF has a special software license charge. Special PR/SM microcode prevents the defined ICF PUs from executing non-CFCC code such as z/OS.
CBU – Capacity BackUp
CFCC – Coupling Facility Control Code
CIU – Customer Initiated Upgrade
CoD – Capacity on Demand
CP – Central Processor
CPC – Central Processor Complex
CPU – Central Processor Unit
CUoD – Capacity Upgrade on Demand
ICF – Internal Coupling Facility
IFL – Integrated Facility for Linux
POR – Power-On Reset
PR/SM – Processor Resource/System Manager
PU – Processor Units
SAP – System Assistance Processor
zAAP – z Application Assist Processor
zIIP – z Integrated Information Processor