Z/OS System Services

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.

Prerequisites

Before this course you should have attended our z/OS Systems Programming Introduction or have equivalent knowledge. 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.

Duration

4 days. Hands on.

Course Objectives

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. After completing this course, you will be able to:

• 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.

Course Content

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