z/OS System Services

Course Overview

This course presents the structure and control blocks of the z/OS BCP and system services. It prepares the z/OS system programmer to identify potential bottlenecks and performance problems, perform initial error symptom gathering, and identify opportunities and requirements for tailoring a z/OS system. This course also provides prerequisite information needed for further training in specialized areas such as system measurement, tuning and problem determination.

Audience

This course is for z/OS system programmers responsible for customization, measurement and tuning, or problem determination of z/OS. Subsystem programmers will also benefit.

Skills Gained

• Explain the z/OS functions and control blocks necessary to support a task in a multitasking and multiprocessing environment
• Describe the software and hardware functions that allow a program to interact with programs running in other address spaces, use data in other address spaces, and use data in data spaces
• Trace the flow of an I/O operation from the initial request in the application program through the completion of data transfer
• Identify the control blocks that describe the current status of an I/O request
• Describe the functions of the z/OS Virtual, Real, and Auxiliary Storage Managers
• Describe the functions performed by the Recovery Termination Manager and recovery management components to minimize failure impact and enhance error correction
• Select the appropriate IBM publication to provide further technical information (SRLs, Technical Bulletins, Self-study and other z/OS courses)
• Describe the services provided by cross system extended services (XES).
• Identify and explain the purpose of the cache, list, & lock structures.
• Plan the implementation of the global resource serialization STAR environment.

Prerequisites

Before this course you should have attended our z/OS Systems Programming Introduction or have equivalent knowledge. Completion of our Assembler Language course is recommended but not essential. You should be able to:

• Describe the z/OS characteristics of multiprocessing, multiprogramming, virtual storage and paging, and multiple address space/data space architecture.
• Explain how paging and swapping are accomplished through the interaction of real/central, expanded, auxiliary, and virtual storage in an z/OS system.
• Explain the role of the dispatcher, interrupts, SVCs, the program manager, and serialization in managing work in an z/OS system.
• State the role of z/OS software and hardware components in handling an I/O request for data on a direct access storage device.

Course Outline

System Introduction

• z/OS Review
• z/OS System Components Review
• Introduction to Control Blocks
• Basics of z/Architecture

Operating Environment Initialization

• System Libraries
• Initial Program Load

Task Management

• Task Dispatching
• Service Request Scheduling
• Program Managing
• Serializing Resources
• Supervisor Calls
• Status Saving on Interrupt

Addressability

• Addressability Review
• Cross Memory Services - Addressability to Two Address Spaces
• Extended Addressability to Multiple Spaces

Input/Output Supervisor

• I/O Definition and Initialization
• I/O Request Flow.
• I/O Interrupt Flow.
• Error Handling

Storage Management

• Storage Management Review
• A Programmer's Use of Storage
• Paging and Swapping
• Coupling Facility Storage.
• Exploitation

Recovery Termination Manager (RTM)

• RTM Overview
• Preparing the Environment
• Normal Termination Processing
• Abnormal Termination Processing
• Recovery Management Support.

Job Scheduling