Options Specific to the MVS Compiler

15.2.1.2 DYNBUF

In MVS the buffers are always acquired dynamically by the compiler. This option is therefore suppressed.

15.2.1.3 LIMSCONV

An option of DOS PL/I to generate strong external references to PL/I conversion library modules only for those conversions deemed ²reasonable² for the data types of variables that appear in GET DATA and GET LIST statements. Without LIMSCONV the whole PL/I conversion is of much less importance in virtual storage systems. MVS PL/I does not support it.

15.2.1.4 LINK

This option is replaced by the conditional execution function offered by MVS JCL. It therefore no longer exists in MVS.

15.2.1.5 NAME

This option is functionally equivalent in the two compilers. The control statement generated for the link edit has of course a different format. It allows, among other compiler possibilities, several independent PL/I programs to be compiled in a single pass and to link-edit these programs in one pass (batched compilations).

15.2.1.6 WORKFILE

This option was used to define the type of compiler workfiles, but has no use in MVS and is suppressed. (The access method modules being loaded dynamically at OPEN, the workfiles are independent of physical units.)

15.2.2 Options Specific to the MVS Compiler

15.2.2.1 GONUMBER

Analogous to the GOSTMT option, it gives the line number in the case of an abnormal termination, for example a conversion error, instead of the number of the instruction. It requires the NUMBER option. This option is used under TSO and CMS, the editors of these two time-sharing systems numbering the lines of the source program.

15.2.2.2 NUMBER

This option informs the compiler that the input is numbered.

15.2.2.3 SEQUENCE

This option indicates to the compiler where to find the line numbers in the source program.

15.2.2.4 STATEMENT

This option requests the compiler to number the instructions of the source program.

336VSE to OS/390 Migration Workbook

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.

IBM OS/390 manual Options Specific to the MVS Compiler

Models: OS/390