IBM mainframe IBM mainframes are large computer systems produced by IBM since 1952. During the 1960s and 1970s, IBM dominated the large computer market. Current mainframe computers in IBM's line of business computers are developments of the basic design of th ...

s running the

z/OS z/OS is a 64-bit operating system for IBM z/Architecture mainframes, introduced by IBM in October 2000. It derives from and is the successor to OS/390, which in turn was preceded by a string of MVS versions.Starting with the earliest: * O ...

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

, Intelligent Resource Director (IRD) is software that automates the management of

CPU A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and ...

resources and certain I/O resources. IRD is implemented as a collaboration between

Workload Manager In IBM mainframes, Workload Manager (WLM) is a base component of MVS/ESA mainframe operating system, and its successors up to and including z/OS. It controls the access to system resources for the work executing on z/OS based on administrator-defi ...

(WLM), a component of z/OS, and the

PR/SM A logical partition (LPAR) is a subset of a computer's hardware resources, virtualized as a separate computer. In effect, a physical machine can be partitioned into multiple logical partitions, each hosting a separate instance of an operating ...

Logical Partitioning (

LPAR A logical partition (LPAR) is a subset of a computer's hardware resources, virtualized as a separate computer. In effect, a physical machine can be partitioned into multiple logical partitions, each hosting a separate instance of an operating ...

)

hypervisor A hypervisor (also known as a virtual machine monitor, VMM, or virtualizer) is a type of computer software, firmware or hardware that creates and runs virtual machines. A computer on which a hypervisor runs one or more virtual machines is calle ...

, a function of the

mainframe A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise ...

hardware. Major IRD functions are: *Logical CP Management - where IRD dynamically varies logical processors on- and off-line. (This does not apply to

zIIP In IBM System z9 and successor mainframes, the System z Integrated Information Processor (zIIP) is a special purpose processor. It was initially introduced to relieve the general mainframe central processors (CPs) of specific Db2 processing load ...

s or

zAAP The IBM System z Application Assist Processor (zAAP), previously known as the zSeries Application Assist Processor, is a mainframe processor introduced by IBM in 2004. zAAP engines are dedicated to running specific Java and XML workloads under z ...

s.) *Weight Management - where IRD dynamically redistributes LPAR weights between members of an LPAR Cluster. (An LPAR Cluster is the set of members of a

Parallel Sysplex In computing, a Parallel Sysplex is a cluster of IBM mainframes acting together as a single system image with z/OS. Used for disaster recovery, Parallel Sysplex combines data sharing and parallel computing to allow a cluster of up to 32 systems ...

on a single

footprint.{{Clarify, date=February 2009) The total of the weights for the LPAR Cluster remains constant as weights are shifted between the members. (

Linux on IBM Z Linux on IBM Z or Linux on zSystems is the collective term for the Linux operating system compiled to run on IBM mainframes, especially IBM Z / IBM zSystems and IBM LinuxONE servers. Similar terms which imply the same meaning are ''Linux/390'', ...

LPARs can also participate in Weight Management.) * CHPID Management - where logical channel paths are moved between members of an LPAR Cluster. IRD's objective is to optimise the use of computing resources while enabling WLM to meet its workload goals. So, for example, IRD will not vary offline logical processors to the point where doing so would cause workloads to miss their goals.

Literature

* Frank Kyne et al., z/OS Intelligent Resource Director, IBM Redbook, SG24-5952

External links

Official z/OS WLM Homepage
IBM mainframe operating systems IBM mainframe technology

See also

Literature

External links