Computer Software and Types of Software

INTRODUCTION

Program or a set of programs is known as Software. Now, What is program? Program is a instruction or set of instructions. So, we can say Computer Programs, namely, the list of  instructions to be executed by a computer are known as the software of a computer. The electronic circuits used in building the computer that executes the software is known as hardware of a computer.   It refers to the physical devices of a computer system, such as Input devices, storage devices, processing unit, control unit , and output devices. A hardware is linked together with software to form a effective working unit that is a computer system.  To take analogy, a home television set bought from a shop is hardware; the various entertainment programs transmitted from the television station are its software. It is immediately evident that hardware is necessary but software is vital. What is the use of a home television set if the programs not transmitted by television station. Another important point brought out by this analogy is that software production is difficult and expensive. Hardware is one-time expense whereas software is a recurring expense.

Thus, there is a special relationship between hardware and software. Both are complementary to each other. Hardware is nothing without software and vice-versa.  By very simple example, these two can be described as both a notebook and a pen are hardware and the written material on notebook is software.

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PL/SQL – An Overview

  • An extension to SQL with design features of programming languages  (procedural and object oriented)
  • PL/SQL and Java are both supported as internal host languages within Oracle products.
  • The PL/SQL procedural language was developed by Oracle Corporation in the late 1980s as procedural extension language for SQL and the Oracle relational database.

Following are notable facts about PL/SQL:

  • It is a completely portable, high-performance transaction-processing language.
  • PL/SQL provides a built-in interpreted and OS independent programming environment.

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Boolean Algebra

BOOLEAN Algebra was developed by George Boole (1815- 1864), an English mathematician and logician.

The credit for applying the laws of Boolean algebra goes to Claude. E. Shannon, an electrical engineer. Claude. E. Shannon in the year 1938, suggested that Boolean algebra can be applied to problems arising in telephone switching circuits and for this reason Boolean algebra is also known as Switching Algebra.

The other noteworthy persons to realise the significance of this algebra were August De- Morgan, Alfred North -White Head and Beltrand Russell.

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Programming with C – Input/Outputs & Decision Making-Lecture 2

Structure of C Program

# include < header file>  // # is pre-processor directive

 #define x  5  //symbolic constant

int a, b;   //global variable declaration

int fxn();  // function declaration

main() //main function

{

int i,j,k;     // local variable declaration

Input statements;

Process;

Output Statements;

}

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