IBM eServer zSeries 990 Technical Guide

56 IBM ^ zSeries 990 Technical Guide

The Storage Assignment function of a Reset Profile on the Hardware Management Console

just shows the total “Installed Storage” and the “Customer Storage”, which is the total

installed storage minus the Hardware System Area (HSA). Logical partitions are still defined

to have Central Storage and optional Expanded Storage. Activation of logical partitions, as

well as dynamic storage reconfiguration, will cause the storage to be converted to the type

needed.

Activation of logical partitions as well as dynamic storage reconfiguration will cause the

storage to be assigned to the type needed (CS or ES). This does not require a Power-on

Reset. No new software support is required to take advantage of this function.

Hardware System Area (HSA)

The Hardware System Area (HSA) is a non-addressable storage area that contains the CPC

Licensed Internal Code and configuration-dependent control blocks. The HSA size varies

according to:

򐂰 The number of defined logical partitions.

򐂰 If dynamic I/O is not enabled, the size and complexity of the system I/O configuration. The

HSA may hold the configuration information for up to 63 K devices per LCSS.

򐂰 If dynamic I/O is enabled, the MAXDEV value specified in HCD or IOCP, in support of

dynamic I/O configuration.

2.2.6 Modes of operation

Figure 2-15 on page 57 shows the z990 modes of operation diagram, summarizing all

available mode combinations that are discussed in this section: z990 mode, image modes

and their processor types, operating system versions and releases, and architecture modes.

There is no special operating mode for the 64-bit z/Architecture mode, as the architecture

mode is not an attribute of the definable images operating mode.

The 64-bit operating systems are IPLed into 31-bit mode and, optionally, can change to 64-bit

mode during their initialization. It is up to the operating system to take advantage of the

addressing capabilities provided by the architectural mode.

The operating systems supported on z990 servers are shown in Chapter 6, “Software

support” on page 133.

Note: The HSA is always allocated in the physical memory of Book 0.

Note: The z990 models only operate in Logically Partitioned Mode. ESA/390 TPF mode is

now only available as an image mode in a logical partition.

Chapter 2. System structure and design 57

Figure 2-15 z990 Modes of operation diagram

Logical Partitioning overview

Logical Partitioning is a function implemented by the Processor Resource/Systems Manager

(PR/SM), available on all z990 servers.

The z990 only runs in LPAR mode. This means that virtually all system aspects are now

controlled by PR/SM functions.

PR/SM is very much aware of the book structure introduced on the z990. However, logical

partitions do not have this awareness. Logical partitions have resources allocated to them

coming from a variety of physical resources, and have no control over these physical

resources from a systems standpoint—but the PR/SM functions do have.

PR/SM manages and optimizes allocation and dispatching work on the physical topology.

Most physical topology knowledge that was previously handled to the operating systems is

now the responsibility of PR/SM.

PR/SM always attempts to allocate all real storage for a logical partition within one book, and

attempts to dispatch a logical PU on a physical PU in a book that also has the central storage

for that logical partition. If not possible, a PU in an adjacent book is chosen. In general,

PR/SM tries to minimize the number of books required to allocate the resources of a given

logical partition. In addition, PR/SM always tries to re-dispatch a logical PU on the same

physical PU to assure that as much as possible of the L1 cache content can be reused.

z990

Mode

Logically

Partitioned

Mode

ESA/390 Mode

ESA/390 TPF Mode

Coupling Facility Mode

Linux Only Mode

31-bit

Architecture

Mode

64-bit

Architecture

Mode

64-bit

Architecture

Mode

31-bit

Architecture

Mode

64-bit

Architecture

Mode

TPF

CFCC

Linux on zSeries

CPs

CPs only

ICFs and/or CPs

IFLs or CPs

z/OS

Linux on zSeries

z/VSE

VSE/ESA

Linux for S/390

Operating System

Option

z/VM

OS/390 R10

Image

Modes

Linux for S/390

31-bit

Architecture

Mode

Operating

Systems

Addressing

Modes

z/VM

Operating System

Option

CPs and zAAPs

(z/OS 1.6 and

above only)