z/OS & JES3 Operations

This two-day course provides a view of z/OS (with JES3 as the job entry subsystem) through the eyes of the operator and the operator console.
The course covers the most relevant commands and activities that could be required by a z/OS/JES3 operator.

This course is available for one-company, on-site presentations and for live presentation over the Internet, via the Virtual Classroom Environment service.


On successful completion of this course you will be able to:

  • describe z/OS & related components
  • use the console to issue MVS commands
  • interpret MVS messages
  • understand how JES3 relates to MVS
  • describe the uses of the master console
  • list the uses of the HMC
  • invoke the IPL process
  • explain the difference between 'cold' and 'warm' starts in z/OS
  • describe the IPL process
  • bring down (stop) the z/OS system
  • list the different device types
  • manage z/OS devices
  • describe the differences between batch, started tasks and TSO
  • start and stop started tasks
  • describe the job flow in JES3
  • display and control jobs in JES3
  • display and control JES3 consoles and devices
  • display and control JES3 output queues
  • control JES3 global functions
  • display MDS queues
  • describe the concept of system dumps
  • manage dump datasets
  • manage system problem situations.

Who Should Attend

MVS/JES3 operators, systems programmers and other technical support personnel who need an understanding of the operational characteristics of z/OS with JES3.


An understanding of the z/OS environment, as taught in the course z/OS Concepts & Facilities, and knowledge of TSO/ISPF and JCL.


2 days

Fee (per attendee)

£1100 (ex VAT)

Course Code



z/OS Introduction

What is an operating system; z/OS overview; z/OS Job Management; Operator roles; Operator communications; z/OS products; DFSMS/MVS; Network software; Application development tools.

JES3 Introduction

Why JES3?; Terminology; Startup; Devices; Console support; Console commands.

Operator Communication - the Console

Console types; Master Console authority; Operating modes; Operator command types; Route codes; Message Levels; z/OS command syntax; Commonly used z/OS commands;; Console message format; Console screen layout; Control (K) command; DISPLAY command; VARY CN command;; SEND command.

IPL process

IPLing z/OS; IPL messages; IPL flow; TOD clock; Stopping z/OS.

I/O Device control

I/O overview; Device types; Channel subsystems; Channels; FICON; Control units; Device numbers; Shared DASD; Offline/online; DISPLAY U command; VARY device command; VARY PATH command.

z/OS Workload and the Active System

Program execution environments; Batch processing; Started Tasks; Time Sharing Option (TSO); Executing program requirements; Program identification with JCL; All the JCL statements; The most used JCL statements; Relationships between JCL statements; One or more jobs in a JCL stream; Getting work into the system; Getting a Started Task into the system; Getting a TSO user into the system; Getting a batch job into the system; The active system; A job's phases; What is a System Task?; What is a TSO logon?

JES3 Job Flow

Processes; Input Service, CI processing; Main device scheduling; GMS; Output service; Purge; Dynamic support programs; Dependent job control; Network Job Entry (NJE).

JES3 Operations

Job status & queues; Console status; Device status; Output queue status; Modify job & job queue status; Modify Output queues Modify GMS options; Control global functions; control writers.

Active MVS job management

Executing in MVS - the address space; Active jobs; DISPLAY active jobs; Examples of DISPLAY activity in MVS; Cancelling jobs; Volume mounts; Examples of MOUNT messages; The REPLY command; Examples of REPLY; DISPLAY requests; Example of DISPLAY R; Started Tasks; The START command; Examples of the START command; The STOP command; Examples of the STOP command; The MODIFY command.

Problem & Dump Management

Non-system problems - ABEND; Job ABEND examples; System failure with recovery; SVC dumps; SVC dump management; Copying SVC dumps; Clearing a dump data set; Full SYS1.DUMP data sets; 'Unusual' messages; 'WTO BUFFER SHORTAGE'; 'CHANNEL DETECTED ERROR'; 'AUXILIARY STORAGE SHORTAGE'; 'SMF DATA LOST'; Outstanding requests - D R; Examples of D R; The entire system hangs; Types of hung system; The Program Status Word; Displaying the PSW; The status in the PSW; Disabled WAIT; Disabled LOOP; Loop trace; Excessive spin loops; Message IEE331A; Default actions on excessive spin loops; Enabled LOOP; Enabled WAIT; Stand-Alone Dump; Taking an SA-Dump.

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