Dos Pl/I, VS Cobol II Migration Considerations

Table 38 on page 356 lists some migration considerations you should be aware of when migrating from VS COBOL II.

Table 38. VS COBOL II Migration Considerations

Migration Consideration	Comments

Abends	In VS COBOL II, a severe unhandled error condition
	always resulted in an abend. With OS/390 Language
	Environment, you use the ABTERMENC run-time option
	to specify whether a severe unhandled condition
	results in an abend or a normal termination with a
	return code and reason code. The IBM-supplied
	installation value for the ABTERMENC run-time option
	is ABTERMENC(RETCODE). To ensure that your
	application ends with an abend when there is a severe
	unhandled condition, specify ABTERMENC(ABEND).

Storage Report	The format of the run-time storage report generated
	by the OS/390 Language Environment RPTSTG
	run-time option is different from the format of the
	storage reports produced by the VS COBOL II SPOUT
	run-time option.

17.4.4 DOS/VS COBOL

DOS/VS COBOL is not an LE/VSE-conforming language. If your applications are written in DOS/VS COBOL, you must update the source and compile with COBOL for MVS & VM or COBOL for OS/390 & VM before you can run them under OS/390. Refer to Chapter 12, ªCOBOLº on page249 for further information.

Table 39 lists some migration considerations you should be aware of when migrating from DOS/VS COBOL.

Table 39. DOS/VS COBOL Migration Considerations

Migration Consideration	Comments

Abends	In DOS/VS COBOL, a severe unhandled error condition
	always resulted in an abend. With OS/390 Language
	Environment, you use the ABTERMENC run-time option
	to specify whether a severe unhandled condition
	results in an abend or a normal termination with a
	return code and reason code. The IBM-supplied
	installation value for the ABTERMENC run-time option
	is ABTERMENC(RETCODE). To ensure that your
	application ends with an abend when there is a severe
	unhandled condition, specify ABTERMENC(ABEND).

17.4.5 DOS PL/I

DOS PL/I is not an LE/VSE-conforming language. If your applications are written in DOS PL/I, you must update the source and compile with PL/I for MVS & VM before you can run them under OS/390. Refer to Chapter 15, ªPL/Iº on page 333 for further information.

Table 40 on page 357 lists some migration considerations you should be aware of when migrating from DOS PL/I.

356VSE 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 Dos Pl/I, VS Cobol II Migration Considerations, DOS/VS Cobol Migration Considerations

Models: OS/390