functional enhancements of the VSE Librarian. The Librarian functions can be invoked through a console or through job streams (JCL).

In OS/390, each of the different utilities used to create and maintain PDS (or PDSE) data sets and their members has a different set of commands and somewhat different syntactical requirements. Combined with OS/390 JCL, the overall functions available are similar to the functions provided for VSE libraries.

Interactive usage

The VSE Librarian runs in batch or interactive mode in static or dynamic batch partitions or interactive partitions of VSE/ICCF; it can attach VSE libraries/sublibraries dynamically through the VSE Librarian commands. This allows the user to move members from any VSE library/sublibraries into the ICCF library and vice versa. All Librarian services can be invoked from VSE consoles or ICCF terminals for all libraries.

The interactive capabilities of the OS/390 Interactive System Productivity

Facility (ISPF) are frequently used in OS/390 environments to perform many of the functions provided by VSE¢s LIBR, such as creating and maintaining

PDSs and their members. For example, it is common in VSE to edit a VTAM startup member (²B-Book²) in ICCF or CMS, and then submit a LIBR job to

replace the system cataloged library member. In OS/390, ISPF facilities permit direct view, edit and replace functions for members in PDSs, so ISPF could be used to directly update the corresponding VTAMLIST member.

22.1.1OS/390 ISPF Overview

ISPF also can be used in the following ways:

As a general source code or document preparation and editing facility.

To monitor and control program libraries.

To communicate with MVS through TSO commands, CLISTs, or REXX EXECs.

To develop a batch, interactive, or any other type of program and its documentation.

To call dialogs that use Dialog Manager (DM) component and Program Development Facility (PDF) component dialog services to do the work of the application.

There are several functions in ISPF to view, browse, and edit partitioned data set members, as well as create and manage data sets. An even more powerful set of tools also exists in the Library Management Facility and Software Configuration Library Manager to manage multiple library levels.

Since ISPF usage is a key to productive use of your OS/390 system, we strongly recommend formal training in its features and the use of its functions. See the following ISPF books for orientation:

SC28-1294 - OS/390 ISPF Getting Started

SC28-1239 - OS/390 ISPF User¢s Guide

390VSE to OS/390 Migration Workbook

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IBM manual 22.1.1 OS/390 Ispf Overview, ∙ Interactive usage

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.