COMPUTER SOFTWARE FOR INFORMATION SYSTEMS
INTRODUCTION
An information system builds both hardware and software are essential, systems being used in organisations are driven by a programs. A program is a set-up stepwise instruction given to a computer to accomplish various tasks. Programs are write software using special languages called programming languages. The process of writing program is referred to as programming. A set of program which instructs the hardware to perform a job is called as software.
PROGRAMMING LANGUAGES
There are two types of programming languages
1. Procedural language.
2. Non-procedural language.
Procedural Language:
A language, which explains stepwise sequential explanation to accomplish a given task, is
called as procedural language.
Non-Procedural Language:
A non-procedural language focuses on what needs to be done, without specifying exactly
how it should be done.
FIRST GENERATION LANGUAGES (MACHINE LANGUAGE):
The early computers were programmed in machine language or 1st generation language.
A series of zeroes & ones then the CPU can interpret & execute. Machine language is important because it is the only language that the computer understands. Since machine language is difficult to use. Computer scientist development, programming language which
more closely resembled human communication.
The program is written in the programmer’s language & is translate into the machine language before it is run.
The program written by the programmer is known as the source program. The machine language is called as the object program.
The system software translate the source program into the object program is called translator.
SECOND GENERATION LANGUAGE (THE ASSEMBLERS):
The 1st translator ware called assemblers. They permitted the programmer to code programs in assembly language or 2nd generation language.
An assembly language mnemonic name for the operations that are to be performed symbolic names for the data that is processed.
• Assembly language was a big improvement over machine language from the programmer’s point of view, but it had several draw backs.
The assemble language programs are to be lengthy and ware difficult for programmers to read.
THIRD GENERATION LANGUAGES (3 GLs)
3rd generation language can produce multiple object program instruction from a signal source program instruction. It means that programmers have to produce fewer lines of code in addition the syntax of 3rd generation language is more like the user’s language.
Compiler produce a complete object program in one process then the object program is executed.
An interpreter translates a source program instruction & executes it before going on the next instruction.
• COBOL, FORTAN & PL/I are compiler language and basic program are interpreter languages.
FOURTH GENERATION LANGUAGES (4GLs)
• 4th generation languages were developed in the 1970 to overcome the demands of procedural programming language.
• 4th generation languages are non-procedural languages. If allow the programmer & users to instruct the computer in what to do rather than how to do it.
• The term natural language is also used because the syntax of the 4th generation language can be very similar to our everyday speech.
• (i) Data base query languages
(ii) Modelling languages
(iii) Very high level languages
(iv)Graph generators
(v)Report writers
(vi)Application generators
Database query language:
It is shown here how a manager can use a data base query language that provides a special report from database contents without the need to code a program. The 4GL used in the example is FOCUS.
Modelling languages: A modelling language is especially designed to make the building of mathematical models easier than when a problem oriented language is used. One of the first modelling languages was GPSS (General purpose simulation system), developed by IBM in
the early 1960s.The most popular ones that followed include DYNAMO, SLAM,
SIMSCRIPT, GASP, MODEL, and IFPS.
Very high level language: The term very high level language is often used to describe a programming language, such as a APL, that offers succinctness and power over and above that of conventional languages.
Graph Generators: A graph generator is also called a graphics package, is used to display or print data in a variety of graphical forms.
Report writers: A report writer is specifically designed to prepare reports. The first example was RPG (Report program generator).COBOL has a report writer feature as do most of the database management systems.
Application Generators: An application generator produces an application program such as inventory or payroll, without programming .Examples are MANTIS and MARKV.
• Maintain usage records
Operating system environment: There are two types of operating system environments:
Multiprogramming: It is a computing environment in which multiple users can run multiple programs on a single CPU computer at the same time. The CPU switches between programs, however at any given time is executing only one program.
Multiprocessing: it is system has a number of processors that process data and instructions, unlike systems that have only one CPU. It is ideally suited for complex and computationally intensive operations that require extensive processing.
System support software: Programs which support the smooth execution of various programs and operations of a computer are called system support software. System support software includes utility programs, programming services software, database management systems, and security software and system documentation.
Utility programs
These are among the most popular types of system support software. The perform tasks such as formatting disks, locating free space on a disk, retrieving lost or damaged files ,sorting and merging data, converting files from one format to another ,backing up important files and providing online help.
Programming services software
It includes
Language translators
System loaders
Link editors,
System librarians.
Database management system
It is a set of computer programs that enables a user to define, create access, manipulate, andoutput the information in records stored on a database.
Security software
It protects a computer system and its files from unauthorized access. Examples of security
software includes
Password programs
File protect programs
Encryption software.
System documentation
It includes manual, flowcharts, reference, guides, and other operating instructions.
System development software:
It helps design and built better system, e.g. a collection of programs that assist developers in developing an information system also called as computer aided software engineering (CASE).
