VS COBOL II AND PRODUCTIVITY IMPROVEMENT - IBM Mainframe

VS COBOL II offers a variety of features that increase programmer productivity and can benefit your organization:

  • ANSI 1985 COBOL Standard support provides the COBOL language features you need for modular design and structured program development. VS COBOL II supports the high subset of ANSI 1985 Standard COBOL under both the MVS and VM operating systems and the intermediate subset under VSE. VS COBOL II offers a variety of features that increase programmer productivity and can benefit your organization:
  • Systems Application Architecture (SAA) support allows the development of consistent COBOL programs.
  • Compatibility and migration features allow your existing OS/VS COBOL or DOS/VS COBOL programs (and earlier releases of VS COBOL II) to coexist with VS COBOL II Release 4. In cases where migration is required, VS COBOL II Release 4 provides features that significantly aid the migration process.
  • Structured programming aids help you design, develop, code, and test programs in an orderly way.

VS COBOL II also features several other productivity enhancements:

  • XA and ESA support allows you to use 31-bit addressing and makes it easier to develop large applications.
  • Enhanced COBOL-CICS interface simply the way you build COBOL programs to be used with CICS.
  • Detailed feedback from VSAM requests provides valuable information about the status of your files.
  • Batch compiling provides flexibility and efficient use of resources.
  • Double-Byte Character Set (DBCS) support allows development of COBOL programs using specialized character sets.

COBOL Standard Encourages Structured Programming

The ANSI 1985 COBOL Standard provides efficient language constructs. These constructs include nested programs, inline PERFORM statements, nested statements using explicit scope terminators, and the EVALUATE statement. Using these constructs will aid in the development of applications that conform to top-down design, modular program development, and structured programming concepts. IBM also provides an extension that allows you to use nested COPY statements.

Structured, or top-down, development is an orderly approach to designing, coding, and testing programs. The term 'top-down' refers to the hierarchic nature of this approach. VS COBOL II offers a structured programming language mat supports program modularity to help improve programmer productivity. VS COBOL II programs are easier to test and debug because program flow and use of language elements that affect program modularity are controlled. In addition, top-down development ensures the use of structured programming language. The VS COBOL II allows:

  • Programs to be designed from the top down
  • Programs to be coded to follow the top-down design
  • Programs to be developed modularly
  • Programs to be tested from the top down

Nested Programs Assist in Top-Down Design

The ANSI J985 COBOL Standard allows you to develop nested COBOL programs. This means that a COBOL source program can contain another COBOL source program, and a contained COBOL source program can in turn contain other COBOL source programs. Each nested program contains:

  • PROGRAM-ID Paragraph - This paragraph may specify the COMMON and INITIAL clauses. The COMMON clause extends accessibility to a program beyond that implied by the nested program hierarchy. The INITIAL clause specifies that when it is called, this program is made available in its initial state. Any programs this program contains are also made available in their initial state when they are first invoked.
  • END PROGRAM Statement - This statement defines the end of a COBOL source program. The END PROGRAM statement includes the same name as the corresponding PROGRAM-ID paragraph.

Nested COPY Statements Encourage Modular Development

The COPY statement has always allowed you to develop program functions that can be stored separately from other program code and then be included in the program at compile time without the run­time overhead that CALL statements require. Use of the COPY statement also ensures that an exact copy of the code is always used. With VS COBOL II, COPY statements can be nested. A COPY statement can include a segment of code that contains COPY statements. And the code included by the nested COPY statement(s) can contain COPY statements that are nested even deeper

Inline PERFORM Statements Make Structured Programming Easy

The inline PERFORM statement, when paired with the END-PERFORM scope terminator, allows performed procedures to be coded directly inline with the PERFORM statement that invokes them. The inline PERFORM statement reduces the complexity of program flow by eliminating transfers of control. And because many control transfers are eliminated, the program logic is much easier to understand.

Explicit Scope Terminators Enhance Nested Statements

COBOL statements can be nested within one another because explicit scope terminators allow you to define precisely the range of each statement. By making the end of scope visually evident, explicit scope terminators make the logic of a program much easier to understand.

The EVALUATE Statement Simplifies Control Path Alternatives

The EVALUATE statement is another construct that allows you to develop and code structured programs. Just one EVALUATE statement allows several alternative paths of execution, clarifying program logic and simplifying program coding. In addition, one EVALUATE statement can take the place of several IF statements.

SAA Offers Application Consistency

Systems Application Architecture (SAA) is a collection of selected software interfaces, conventions, and protocols published by IBM. SAA can be the framework for developing consistent applications across current and future offerings of the four major IBM computing environments:

  • MVS
  • VM with CMS
  • Operating System/400(OS/400)
  • Operating System/2 (OS/2)

These interfaces, conventions, and protocols can provide enhanced consistency in the following areas:

  • Programming interfaces - The languages and services that application developers use in building software
  • User access - The design and use of screen panels and user interaction techniques
  • Communications support - The connectivity of systems and programs
  • Applications - The software built and supplied by IBM and other vendors.

SAA can benefit organizations that need access to data on one system today and on another system tomorrow. The programs that run on each of the systems are similar, and the actions performed while running these programs are also similar. The appearance and behavior of panels and keyboards will often be the same, reducing the amount of time needed to train users and increasing the efficiency of your data processing shop. VS COBOL II delivers the SAA COBOL interface for System/370 environments. Programmers can use VS COBOL II to develop SAA COBOL source code that can easily be transported from a System/370 to an AS/400 or a Personal Computer. In addition, the availability of consistent SAA services provides for the portability of all the basic elements of a complete application. As a result of the consistency and portability of application skills throughout SAA, application development programming can be more productive and flexible.

VS COBOL II Offers Compatibility and Migration Features

With the exception of three minor language element differences, VS COBOL II Release 4 offers full source and object code compatibility with VS COBOL II Release 3.0, Release 3.1, and Release 3.2. In addition, most object modules produced by OS/VS COBOL, DOS/VS COBOL, and previous releases of VS COBOL II will continue to provide the same run-time results when using the Release 4 run-time library. It is not necessary to recompile your source programs to produce new object modules.

Object programs compiled under VS COBOL II Release 4 are portable between the MVS, VM, and VSE operating systems. Functions and services used on the source system must be compatible and available on the target system. Portability of VS COBOL II object programs can be similarly exercised among the MVS, VM, and VSE CICS transaction processing environments (provided that the functions and services of the CICS environments are compatible).

VS COBOL II Release 4 supports the ANSI 1985 COBOL Standard. Implementation of this standard required that some language elements exhibit different behavior from that implemented by VS COBOL II Release 2. VS COBOL II provides for coexistence of existing applications that contain these elements, as well as a flagging feature to identify them. If migration from OS/VS COBOL, DOS/VS COBOL, or earlier releases of VS COBOL II is necessary, then VS COBOL II Release 4 provides a number of features that will aid in this migration.

VS COBOL II Eases Debugging and Maintenance

VS COBOL II has a variety of tools that make it easier for you to maintain your programs, and to isolate and fix errors in them. Some of these tools are also useful when you are making planned upgrades to existing applications.

VS COBOL II offers a debugging tool called COBTEST. COBTEST provides a flexible way to examine, monitor, and control VS COBOL II programs. It increases programmer productivity during the development cycle by expediting the debugging and tuning of programs. Under MVS and CMS, you can use COBTEST interactively in either line or full-screen modes; under MVS, CMS, and VSE, you can use COBTEST in batch mode. VS COBOL II also offers other significant debugging and maintenance features, including:

  • Formatted dumps
  • Abend information
  • Compiler listings

These features provide you with specific program information using easy-to-read and easy-to-understand formats.


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