The Integrated Facility for Linux
(IFL) is an IBM mainframe
processor dedicated to running the Linux
operating system, with or without z/VM
. IFLs are one of three types of IBM mainframe processors expressly designed to reduce software costs. (The other types are zAAP
for Java code and zIIP
for DB2.) Microcode
restricts IFLs to Linux workload by omitting some processor instructions not used by the Linux kernel. As with zAAPs
, IFLs are not specifically optimized to run Linux
faster or better.
IBM introduced IFLs on September 29, 2000. At the same time, IBM introduced a special Linux-only VM-like product, called the S/390 Virtual Image Facility for Linux, to cater to IT staff previously unfamiliar with IBM mainframes. IBM soon discovered that z/VM
was not too difficult for new IT staff to learn (and worked better), so IBM discontinued S/390 Virtual Image Facility for Linux in April 2002.
Potential customers can purchase IFLs for all IBM mainframes as far back as the G5 series
also offered IFLs on certain models. An IFL is not required to run Linux — Linux runs on general purpose processors (CPs) as well. IFLs simply cost less.
Support for IFL
Ivory Server for z/Linux from provides support for IFL
processors. (Ivory Server also provides support for zIIP