Chapter 2. AN INTRODUCTION TO PROGRAMMING IN COBOL/400
CHAPTER OBJECTIVES
Upon completion of this chapter, you should be able to
Explain the history of the COBOL programming language.
Explain the program development process.
Explain how program testing can be accomplished.
Identify the different parts of the COBOL coding sheet.
Identify the different DIVISIONs and SECTIONs of a COBOL program.
TYPES OF COMPUTER PROGRAMS
A program is a set of instructions that enable a computer to process data. There are two types of computer programs: operating system programs, which control the overall operations of the computer, and application programs, which actually perform tasks required by users. The term used to describe all types of programs is software.
OPERATING SYSTEM SOFTWARE
All programs run under the control of an operating system. An operating system is a series of programs that monitor and control the overall operations of the computer. The programs that make up the operating system are normally supplied by the manufacturer and are designed to be the interface between the users of the computer system and the lower-level hardware layer.
Numerous operating systems are available for mainframe computers, mid-range computers, including the iSeries and AS/400, and microcomputers. The operating system of the iSeries and AS/400 computer system is called OS/400. OS is an abbreviation for operating system.
APPLICATION PROGRAMS
The top level of the iSeries and AS/400 architecture is the application software. ...
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