S E Q F L D =

SRCH= of XDFLD

S E Q V A L =

SUBSEQ= of XDFLD

S U P V A L =

NULLVAL= of XDFLD

S U P R T N =

EXTRTN= of XDFLD

The non-ACCESS statement approach consists of an LCHILD and XDFLD following the target segment, SEGM statement, in the data portion of the database. Associated FIELD statements are needed in data DBD if /sx or /ck are used. An index DBD defining the index database with its LCHILD statement referencing the target segment in the database is also required.

8.1.4 Program Specification Block (PSB)

The following will require changes to the PSB.

∙

∙

∙

The PSB LANG= parameter must be COBOL, PL/I, PASCAL, ASSEM, or blank for IMS/ESA

No trailing blanks are permitted. Alternative spellings of ′PL.I′ will have to be changed.

Supported languages include ADA, C, OS/VS/COBOL, VS COBOL, C/370, Pascal, PL/I, RPG/370, REXX, and Assembler.

Automatic Field Start Calculation SENFLD

IMS/ESA requires coding of START= parameter in SENFLD of PCB.

The following field level sensitivity extensions of DL/I are not available in IMS/ESA. If you have used these functions, program changes may be required.

1.Virtual Fields

2.Field Types Z,E,D,L

3.Automatic Data Conversion

4.Field Exit Routines

8.1.5Batch Programming

8.1.5.1RPG II

These applications will need to be converted to RPG/370 or some other IMS/ESA supported language.

8.1.5.2 Interactive Macro Facility (IMF)

DL/I DOS/VS Interactive Resource Definition and Utilities (5746-XX1) provides the Interactive Macro Facility (IMF) and Interactive Utility Generation (IUG) functions. MVS ISPF/PDF may be used for these functions. The specific panels and worksheets provided by IMF and IUG are not provided by MVS ISPF/PDF.

8.1.5.3 Command-Level Coding (HLPI)

Assembler, PL/I and COBOL are supported. CICS supplies the translator.

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IBM OS/390 manual Program Specification Block PSB, Batch Programming, 5.1 RPG
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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.
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