12.4.2ENVIRONMENT DIVISION

12.4.2.1CONFIGURATION SECTION - SPECIAL-NAMES Paragraph

UPSI Switch Processing

In DOS/VS COBOL and COBOL for OS/390 and VM, program switches can be tested by use of a one-byte switch in the SPECIAL-NAMES paragraph, specified as UPSI-0through UPSI-7.

In VSE, the setting of these program switches at execution time is achieved by the // UPSI job control statement.

In OS/390 the // UPSI job control statement is not available. Passing information at execution time is achieved by the PARM field of the EXEC statement.

You set your program switches at execution time by using

PARM=′ / UPSI(nnnnnnnn)′ on your OS/390 EXEC statement.

The following example shows an implementation of program switch processing using COBOL for OS/390 and VM in OS/390.

SPECIAL-NAMES.

SYSIN

is ACCEPT-SYSIN

UPSI-0

IS CBL232B ON STATUS IS CBL232-BASE

UPSI-1

IS CBL232C ON STATUS IS CBL232-CURRENT.

//TEST EXEC PGM=PROG1,PARM=′ / UPSI(10000000)′

12.4.2.2 INPUT-OUTPUT SECTION - I-O-CONTROL

MULTIPLE-FILE Clause (Tapes)

In DOS/VS COBOL this clause allows the specification of the relative positions of files on a multi-file unlabeled tape volume. In COBOL for OS/390 and VM it is syntax checked but has no effect on the execution of the program. The function is performed by the system through the LABEL parameter of the DD job control statement.

APPLY Clauses

In DOS/VS COBOL, there are seven formats for the APPLY clause:

APPLY WRITE-ONLY

APPLY EXTENDED-SEARCH

APPLY WRITE-VERIFY

APPLY CYL-OVERFLOW

APPLY MASTER-INDEX

APPLY CYL-INDEX

APPLY CORE-INDEX

In COBOL for OS/390 and VM only APPLY WRITE-ONLYis available. However the restrictions that applied to APPLY WRITE-ONLYin DOS/VS COBOL do not apply in COBOL for OS/390 and VM.

Chapter 12. COBOL 255

Page 278 Page 280
Page 279
Image 279
IBM OS/390 manual Configuration Section SPECIAL-NAMES Paragraph, SPECIAL-NAMES Sysin, Is ACCEPT-SYSIN
Page 278 Page 280

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.
Top Page Image Contents