Chapter 27. Orienting ICCF Users to TSO/ISPF

There are many facets of VSE/ICCF that are done differently in OS/390. TSO along with ISPF and SDSF provide functions that were previously done using VSE/ICCF.

27.1 TSO/ISPF and SDSF

ISPF is a dialog manager and runs under TSO on OS/390. ISPF provides a powerful environment that can be used for both development activities along with job submission. SDSF extends this environment by providing facilities that allow for both job monitoring and job output viewing. These tools are normally used by system programmers, application programmers and production control personnel.

ISPF is actually several distinct ²features² integrated together:

∙Dialog Manager (DM) provides services for application developers to easily create and display applications, including Display Services, Variable Services, Table Services, and File Tailoring Services.

∙Program Development Facility (PDF) provides utilities and services for application developers to create and maintain applications, including Edit, View, and Browse, a wide range of data set utilities, and foreground and batch compilers.

∙Software Configuration and Library Manager (SCLM) provides a robust environment for controlling a software development environment and tools to manage the environment.

∙ISPF Client/Server provides application developers with the ability to both

incorporate the workstation into the development process and use it to run applications. Existing ISPF applications will run ¢in GUI mode¢ with no

changes, and a set of distributed services are available to edit and build using workstation tools.

∙VisualAge ISPF, a visual development solution utilizing the composition editor of IBM¢s VisualAge technology, can be used to create new ISPF panels

and modify existing ISPF panels for use on 3270 and GUI screens.

∙An ISPF Application Server and ISPF Workstation Agent Applet allows legacy (and new) ISPF applications to be accessible from the World Wide Web.

Other functions provided by ISPF include:

∙Ability to communicate with OS/390 through TSO commands, CLISTs or REXX EXECs.

∙Ability to split the physical display screen into two or more logical screens (ISPF enables a maximum of 32). The logical screens are treated as though they are independent ISPF sessions. For example, one could edit two members of a partitioned data set, or view error messages in the output of a compile job while editing the source.

∙Ability to use referral lists for data set selection from the View Entry, Edit Entry, and most of the Utilities panels. Reference lists are active lists of data sets and libraries that you have referenced in your ISPF session. You can

© Copyright IBM Corp. 1998

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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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