28.3 Controlling the OS/390 System

The OS/390 System commands are only a subset of the commands necessary to operate the system. JES2, VTAM, and many other OS/390 components also have a command language which is used to operate their subsystems. We recommend that systems programmers and operators attend a class on basic OS/390 (MVS) and JES2 facilities. In addition, there are more advanced classes such as the ²CMOS Complex Systems Availability and Recovery² (five days).

This section is for a new operator controlling a single OS/390 system using MCS consoles with JES2 and SDSF.

28.3.1 Starting the System

Here is an overview of the steps to start OS/390:

1.Prepare the System Hardware (power on, IML, and configure)

2.Load the System Software (IPL-ing MVS)

3.Specify the System Parameters

4.Set the Time and Date (if required)

5.Start JES2 - ²S JES2,PARM=NOREQ²

6.Start VTAM - ²S NET,,,LIST=xxx²

7.Start TSO - ²S TSO²

8.Start RMF - ²S RMF²

9.Start other subsystems, such as Automation, CICS and so on

These commands can be automated in the COMMANDxx member of parmlib, or through some other automation product, so they do not have to be entered by a human operator.

28.3.2 Displaying System Status

Depending what you want to display, you can either enter an MVS command, a JES2 command, use SDSF, or use another subsystem display.

The MVS ²DISPLAY² command (abbreviated ²D²) has many different objects and parameters. Here are some basic ²D² commands:

D R,L - List all outstanding WTOR messages awaiting reply

D R,U - List all outstanding Mount Requests (for example, tape mounts)

D A,L - List Active Jobs, TSO users, and Started Tasks

D D,S - Display the Dump Options

D SMF - Display the SMF status

D LOGREC - Display the status of LOGREC

D TRACE - Display the status of TRACE

D C - Display Console configuration

There are many other Display commands and parameters. See section 4.9 in

MVS Commands for the details.

Chapter 28. Orientation to OS/390 Console Operation 447

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OS/390 specifications

IBM OS/390, a versatile operating system, was a cornerstone in enterprise environments and played a pivotal role in mainframe computing. Released in the mid-1990s, OS/390 combined the strengths of IBM's MVS (Multiple Virtual Storage) with new features and enhancements, targeting scalability, reliability, and performance in demanding business applications.

One of the key features of OS/390 was its robust support for multiple users and processes. The system allowed thousands of concurrent users to access applications and data, ensuring high availability and minimizing downtime—a critical requirement for many large organizations. This scalability was supported through various enhancements in memory management and processor scheduling, enabling optimal resource allocation across diverse workloads.

OS/390 was known for its superior workload management capabilities. The Workload Manager (WLM) component allowed administrators to define service policies, specifying how system resources would be allocated according to the priority of tasks. This ensured that critical business processes received the necessary resources while less critical tasks were managed more flexibly.

Another significant characteristic of OS/390 was its commitment to security. The operating system provided comprehensive security features, including user authentication, data encryption, and auditing capabilities. This focus on security was vital for organizations handling sensitive data, ensuring compliance with regulations and safeguarding against unauthorized access.

OS/390 also supported advanced technologies that facilitated integration and development. The system included features like the IBM CICS (Customer Information Control System) for transaction processing and IMS (Information Management System) for database management. These technologies allowed organizations to build robust, high-performance applications tailored to specific business needs.

The ease of network integration was another strength of OS/390. With the advent of the Internet and global connectivity, OS/390 systems could easily interface with various network protocols, enabling businesses to operate in a connected world. This inclusion paved the way for many organizations to expand their capabilities and offer new services, driving digital transformation.

In conclusion, IBM OS/390 represented a significant advancement in mainframe technology, combining scalability, security, and robust workload management. Its rich feature set and support for critical enterprise applications solidified its role as a vital component of many organizations' IT infrastructures, ensuring they could meet their operational challenges head-on while supporting future growth. As technology continues to evolve, the legacy of OS/390 remains influential in the realm of computing.
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