6947ch01.fm Draft Document for Review April 7, 2004 6:15 pm
4 IBM eServer zSeries 990 Technical Guide
򐂰4-port ESCON cards
򐂰OSA-2 cards
򐂰OSA-Express ATM cards
򐂰Pre-FICON Express cards
򐂰PCICC cards
The logical partitioning facility, PR/SM, provides the ability to configure and operate as many
as 30 logical partitions. PR/SM manages all the installed and enabled resources (processors,
memory) of the installed books as a single large SMP. Each logical partition has access to
physical resources (processors, memory, I/O) in the whole system across multiple books.
1.2 z990 models
The z990 has a machine type of 2084 and has four models: A08, B16, C24, and D32. The
model naming is representative of the book design of the z990, as it indicates the number of
books and the number of processor units available in the configuration. PUs are delivered in
single increment, orderable by feature code. A Processor Unit (PU) can be characterized as a
Central Processor (CP), Integrated Facility for Linux (IFL), Internal Coupling Facility (ICF),
zSeries Application Assist Processor (zAAP) or System Assist Processor (SAP).
The development of a multi-book system provides an opportunity for customers to increase
the capacity and/or requirements of the system in three areas:
򐂰You can add capacity by activating more CPs, IFLs, ICFs, or zAAPs on an existing book
concurrently.
򐂰You can add a new book concurrently and activate more CPs, IFLs, ICFs, or zAAPs.
򐂰You can add a new book to provide additional memory and/or STIs to support increasing
storage and/or I/O requirements. The ability to LICCC-enable more memory concurrently
to existing books is dependent on enough physical memory being present. Upgrades
requiring more memory than physically available are disruptive, requiring a planned
outage.

General rules

All models utilize a 12 PU MCM, of which eight are available for PU characterization. The
remaining four are reserved as two standard SAPs and two standard spares.
Model upgrades, from A08 to B16, from B16 to C24, or from C24 to D32 are achieved by
single book adds.
The model number designates the maximum number of PUs available for an installation to
use. Using feature codes, customers can order CPs, IFLs, ICFs, zAAPs, and optional SAPs,
unassigned CPs and/or unassigned IFLs up to the maximum number of PUs for that model.
Therefore, an installation may order a model B16 with 13 CP features and three IFL features,
or a model B16 with only one CP feature.
Unlike prior processor model names, which indicate the number of purchased CPs, z990
model names indicate the maximum number of processor units potentially orderable, and not
the actual number that have been ordered as CPs, IFLs, ICFs, zAAPs or additional SAPs. A
software model notation is also used to indicate how many CPs are purchased and software
should be charged for. See “Software models” on page63 for more information.

Model upgrade paths

With the exception of the z900 Model 100, any z900 model may be upgraded to a z990
model. With the advance of Linux for S/390 and Linux on zSeries, customers may choose to