Migrating Interlanguage Communications Applications

17.4.6 VS FORTRAN

If your VSE applications are currently written in VS FORTRAN, you must convert them to another version of the FORTRAN compiler before you can run them under OS/390. There is currently no LE/VSE-conforming FORTRAN compiler, so you must convert your VS FORTRAN applications to the OS/390 version of VS FORTRAN. You should read the Language Environment V1R5 FORTRAN Migration Guide for information about migrating to Language

Environment-enabled FORTRAN.

17.4.7 Migrating Interlanguage Communications Applications

Interlanguage communications (ILC) applications are applications built of two or more high-level languages (HLLs), and, frequently, Assembler. ILC applications run outside the realm of a single language′s environment, which creates special conditions, such as how each language maps data, how conditions are handled, or how data can be called and received by each language.

If your ILC applications are built only of two or more LE/VSE-conforming HLLs, then migrating them to OS/390 Language Environment is the same as migrating applications in one LE/VSE-conforming language. This section considers the migration of ILC applications with two or more non-LE/VSE-conforming language.

Table 41 gives information about the migration of ILC applications with various combinations of non-LE/VSE-conforming languages.

Table 41 (Page 1 of 2). ILC Migration Considerations

To Migrate:	You Need To:

A phase containing one or more DOS/VS	1.	Upgrade the DOS/VS COBOL source
COBOL programs, with calls to or from		code, and compile with COBOL for
DOS PL/I		OS/390 and VM or COBOL for MVS
		& VM.
	2.	Upgrade the DOS PL/I source code,
		and compile with PL/I for MVS and
		VM.
	3.	Link-edit the load module with
		OS/390 Language Environment.

A phase containing one or more VS	1.	Upgrade the DOS PL/I source code,
COBOL II programs, with calls to or from		and compile with PL/I for MVS and
DOS PL/I		VM.
	2.	Transfer the VS COBOL II object
		code to OS/390.
	3.	Link-edit the load module with
		OS/390 Language Environment.

A phase containing one or more DOS/VS	1.	Upgrade the DOS/VS COBOL source
COBOL programs, with calls to or from		code, and compile with COBOL for
C/370		OS/390 and VM or COBOL for MVS
		& VM
	2.	Upgrade the C/370 source code, and
		compile with OS/390 C/C++ .
	3.	Link-edit the load module with
		OS/390 Language Environment.

358VSE 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 Migrating Interlanguage Communications Applications, To Migrate You Need To, Dos Pl/I

Models: OS/390

17.4.6 VS FORTRAN

17.4.7 Migrating Interlanguage Communications Applications

Table 41 (Page 1 of 2). ILC Migration Considerations

To Migrate:

You Need To:

DOS PL/I

358VSE to OS/390 Migration Workbook

OS/390 specifications