Chapter 2. System structure and design 47
Draft Document for Review April 7, 2004 6:15 pm 6947ch02.fm
򐂰An Internal Coupling Facility (ICF)
The number of CPs, IFLs, ICFs, zAAPs, or SAPs assigned to particular models depends on
the configuration. The z990 12-PU MCMs have two SAPs as standard. The standard number
of SAPs in a model A08 is two; there are four in a B16; six in a C24; and eight in a D32.
Optional additional SAPs may be purchased, up to two per book.
The z990 12-PU MCMs have two spares PUs as standard. The standard number of spares in
a model A08 is two; there are four in a B16; six in a C24; and eight in a D32. The number of
additional spare PUs is dependent on the number of books in the configuration and how many
PUs are non-characterized.
Central Processors
A Central Processor is a PU that has the z/Architecture and ESA/390 instruction sets. It can
run z/Architecture, ESA/390, Linux, and TPF operating systems, and the Coupling Facility
Control Code (CFCC).
The z990 can only be used in LPAR mode. In LPAR mode, CPs can be defined as dedicated
or shared to a logical partition. Reserved CPs can be defined to a logical partition, to allow for
non-disruptive image upgrades. The z990 can have up to 32 CPs.
All CPs within a z990 configuration are grouped into a CP pool. Any z/Architecture, ESA/390,
Linux, and TPF operating systems, and CFCC can run on CPs that are assigned from the CP
pool.
Within the limit of all non-characterized PUs available in the installed configuration, CPs can
be concurrently assigned to an existing configuration via Capacity Upgrade on Demand
(CUoD), Customer Initiated Upgrade (CIU), On/Off Capacity on Demand (On/Off CoD), or
Capacity BackUp (CBU). More information about all forms of concurrent CP adds are found in
“Capacity upgrades” on page 185.
If the MCMs in the installed books have no available PUs left, the assignment of the next CP
may result in the need for a model upgrade and the installation of an additional book. Book
installation is a non-disruptive action, but will take more time than a simple Licensed Internal
Code upgrade. Only if reserved processors have been defined to a logical partition—and
when the operating system supports the function—can additional CP capacity be allocated to
the logical partition dynamically.
Integrated Facilities for Linux
An Integrated Facility for Linux (IFL) is a PU that can be used to run Linux on zSeries, Linux
for S/390, or Linux guests on z/VM operating systems. Up to 32 PUs may be characterized as
IFLs, depending on the z990 model. IFL processors can be dedicated to a Linux or a z/VM
logical partition, or be shared by multiple Linux guests and/or z/VM logical partitions running
on the same z990 server. Only z/VM, Linux on zSeries, and Linux for S/390 operating
systems can run on IFL processors.
All PUs characterized as IFL processors within a configuration are grouped into the
ICF/IFL/zAAP processor pool. The ICF/IFL/zAAP processor pool appears on the hardware
console as ICF processors. The number of ICFs shown is the sum of IFL, ICF, and zAAP
processors on the server.
IFLs do not change the software model number of the z990 server. Software product license
charges based on the software model number are not affected by the addition of IFLs.