IBM eServer zSeries 900 Technical Guide

Chapter 2. zSeries 900 system structure 29

򐂰 For general purpose CPs, ICFs and IFLs, non-crypto CP sparing starts from the highest

and continues in descending order:

a. Spare with the non-crypto PU spares until they are all used.

b. Next, spare with CE 1’s dual path.

c. As a last resort, spare with CE 0’s available dual path.

򐂰 For SAPs, sparing starts from the top and continues in descending order:

a. Use non-dual path spares until they are all used.

b. If a non-dual path spare is not available, then use:

• The dual path for CE 1

• As last resort, the dual path for CE 0

c. If SAP sparing is not possible and this is a Master SAP (MSAP) (“slave” SAPs are not

reassigned), proceed with MSAP reassignment as follows:

• Highest available PU that is varied off (soft deconfigured)

• Highest available slave SAP

• Highest non-crypto CP not in a dedicated logical partition and in wait state

• Highest non-crypto CP in a dedicated logical partition and in wait state

• Highest available non-crypto CP that is not in a dedicated logical partition and is in

problem state

• Highest available non-crypto CP that is not in a dedicated logical partition and is in

supervisor state

• Highest available non-crypto CP that is in a dedicated logical partition and is in

problem state

• Highest available non-crypto CP that is in a dedicated logical partition and is in

supervisor state

• Highest crypto CP not in a dedicated logical partition and in wait state

• Highest crypto CP in a dedicated logical partition and in wait state

• Highest available crypto CP that is not in a dedicated logical partition and is in

problem state

• Highest available crypto CP that is not in a dedicated logical partition and is in

supervisor state

• Highest available crypto CP that is in a dedicated logical partition and is in problem

state

• Highest available crypto CP that is in a dedicated logical partition and is in

supervisor state

2.3 Modes of operation

Figure 2-6 on page 30 shows the z900 modes of operation diagram, which summarizes all

available combinations of CPC modes, image modes, processor types, operating systems,

and architecture modes, that are discussed in this section.

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 z900 servers are shown in Chapter 7, “Software

support” on page 227.

Note: ICFs and IFLs are never used for MSAP reassignment.

30 IBM eServer zSeries 900 Technical Guide

Figure 2-6 z900 Modes of Operation diagram

All z900 models (except the Model 100) can operate either in Basic Mode or in Logically

Partitioned Mode. The Coupling Facility model 100 can operate only in Logically Partitioned

Mode.

Logical Partitioning overview

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

(PR/SM), available on all z900 servers.

PR/SM enables z900 servers to be initialized for logically partitioned operation, supporting up

to 15 logical partitions. Each logical partition can run its own operating system image in any

image mode, independently from the other logical partitions. A logical partition can be

activated or deactivated at any time, but a new logical partition can only be added disruptively,

as it requires a Power-On-Reset (POR). Some LPAR functions and facilities may not be

available to all operating systems, as they may require software corequisites.

IFL and ICF processors can only be used in LPAR mode.

Each logical partition has the same resources as a “real” CPC, which are:

z900 CPC

Modes

ESA/390

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 for zSeries

CPs

only

CPs

only

ICFs

and/or

CPs

IFLs

or

CPs

z/OS

Linux for zSeries

OS/390 pre R10

VM/ESA

VSE/ESA

Linux for S/390

Operating System

Option

z/VM

OS/390 R10

ESA/390 TPF

Mode

Image

Modes

Linux for S/390

31-bit

Architecture

Mode

Operating

Systems

Addressing

Modes

z/VM

Operating System

Option