ALPHABET

END-COMPUTE

FALSE

OVERRIDE

ALPHABETIC-LOWER

END-DELETE

FUNCTION

PACKED-DECIMAL

ALPHABETIC-UPPER

END-DIVIDE

GLOBAL

PADDING

ALPHANUMERIC

END-EVALUATE

INHERITS

PROCEDURE-POINTER

ALPHANUMERIC-EDITED

END-IF

INITIALIZE

RECURSIVE

ANY

END-INVOKE

INVOKE

REFERENCE

BINARY

END-MULTIPLY

KANJI

REPLACE

CANCEL

END-PERFORM

LENGTH

REPOSITORY

CLASS

END-READ

LINAGE-COUNTER

RETURNING

CLASS-ID

END-RETURN

LOCAL-STORAGE

SELF

COMMON

END-REWRITE

METACLASS

SHIFT-IN

CONTENT

END-SEARCH

METHOD

SHIFT-OUT

CONTINUE

END-START

METHOD-ID

SORT-CONTROL

CONVERTING

END-STRING

NULL

SORT-MESSAGE

DAY-OF-WEEK

END-SUBTRACT

NULLS

STANDARD-2

DBCS

END-UNSTRING

NUMERIC-EDITED

SUM

DISPLAY-1

END-WRITE

OBJECT

SUPER

EGCS

EVALUATE

ORDER

TEST

END-ADD

EXTERNAL

OTHER

TRUE

END-CALL

 

 

 

Figure 22. Reserved Words in COBOL for OS/390 and VM and not in DOS/VS COBOL

Some words which are not reserved in DOS/VS COBOL are COBOL ANSI 85 standard reserved words for a feature not supported by COBOL for OS/390 and VM. If used in a program, it is recognized as a reserved word and flagged with a severe message. These words are listed in Figure 23.

If you used any of these words in your DOS/VS COBOL programs, you will need to replace them.

CD

EMI

PRINTING

SUB-QUEUE-3

COMMUNICATION

ENABLE

PURGE

TABLE

DESTINATION

END-RECEIVE

QUEUE

TERMINAL

DISABLE

ESI

SUB-QUEUE-1

TEXT

EGI

MESSAGE

SUB-QUEUE-2

 

Figure 23. Reserved Words in COBOL for OS/390 and VM for Unsupported Features

The words listed in Figure 24 are COBOL for OS/390 and VM compiler directing words. If they are used as a user-defined word, they will be flagged with a severe message.

If you used these words in your DOS/VS COBOL programs, you will need to replace them.

CBLTITLE

Figure 24. Compiler Directing Words in COBOL for OS/390 and VM

264VSE to OS/390 Migration Workbook

Page 288
Image 288
IBM OS/390 manual EMI Printing, Cbltitle

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.