4.3.12 Comparison of VSE and MVS JCL - A Summary

Below is a summary of VSE JCL statements and possible equivalents in MVS.

Table 7 (Page 1 of 2). VSE Job Control Statements Summary

VSE

Function

MVS Equivalent

Statement

 

 

 

 

 

ASSGN

Used at execution time to assign a

// DD UNIT=

 

specific device address to the

 

 

symbolic unit name used.

 

 

 

 

CLOSE

Closes either a system or a

No equivalent in OS/390.

 

programmer logical unit assigned to

Units closed automatically

 

tape, disk, or diskette.

at end-of-step, or by the

 

 

application program.

 

 

 

DATE

Contains a date that is put in the

No equivalent in OS/390.

 

communications region.

 

 

 

 

DLBL

Contains file label information for

// DD DSName=

 

disk or diskette label checking and

 

 

creation.

 

 

 

 

EXEC

Indicates the end of job control

// EXEC PGM= (Must

 

statements for a job step and that

precede DD statements for

 

the job step is to be executed.

the step.)

 

 

 

EXEC PROC

Calls a cataloged procedure and

// EXEC PROC= (²P R O C = ²

 

defines values for symbolic

is optional)

 

parameters.

 

 

 

 

EXTENT

Defines each area, or extent, of a

// DD VOLUME= SPACE=

 

disk file or diskette volume.

D A T A C L A S =

 

 

 

GOTO

Causes JCL to skip all following

No direct equivalent in

 

statements (except JOB, /&, /+) up

OS/390. Use CONDitional

 

to the specified label statement.

step processing or

 

 

IF/THEN/ELSE/ENDIF

 

 

 

ID

Used to specify user identification

// JOB U S E R =

 

and password.

PASSWORD=

 

 

 

IF

Causes skipping or execution of the

// IF

 

following statement dependent on

 

 

the specified condition.

 

 

 

 

JCLEXIT

Activates or deactivates one or

Not applicable in OS/390.

 

more JCL exit routines.

 

 

 

 

JOB

Indicates the beginning of control

// JOB

 

information for a job.

 

 

 

 

LIBDEF

Defines library chains.

// STEPLIB DD,

 

 

// STEPCAT DD, or

 

 

// JCLLIB

 

 

 

LIBDROP

Drops library chain definitions.

No equivalent in OS/390.

 

 

 

LIBLIST

Lists library chain definitions.

No equivalent in OS/390

 

 

 

LIBSERV

Controls 3494 tape system.

No equivalent in OS/390

 

 

 

LISTIO

Used to get a listing of I/O

No equivalent in OS/390

 

assignments on SYSLOG or SYSLST.

 

 

 

 

MTC

Controls operations on magnetic

// DD LABEL

 

tapes.

 

 

 

 

86VSE to OS/390 Migration Workbook

Page 109 Page 111
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IBM OS/390 manual Comparison of VSE and MVS JCL a Summary, 1 of 2. VSE Job Control Statements Summary
Page 109 Page 111

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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