1.13 Types of software

Software is a set of instructions that controls your computer hardware. A computer system requires two types of software:

• Operating system

• Application

With an operating system and the correct software application, you can perform many tasks with your computer including:

• Word processing

• Accounting

• Desktop publishing

• Database management

• Multimedia presentations

• Graphics creation

• Sending e-mail

• Browsing the World Wide Web (Internet)

When discussing software, people often use the terms program, software, and application interchangeably. When using these terms, a person is usually referring to a specific brand name of software application, such as Microsoft Word.

A computer requires a set of detailed step by step instructions called software or computer program that directs a computer how to perform a specific task. At one time organizations and individuals had to write most of the software they wanted to use. But today most organizations purchase commercially written programs. Even then working as a computer programmer for a business, government agency or software publisher is a challenging carrier. In practice the term software is used to describe a commercial product which might include more than a single program. There is no such thing as "software’s" or "one software". The term "SOFTWARE PACKAGE" is used when dealing with a particular example of software. Software package contains disks or a CD-ROM and a reference manual.

System Software

System software will come provided with each computer and is necessary for the computers operation. This software acts as an interpreter between the computer and user. It interprets your instructions into binary code and likewise interprets binary code into language the user can understand. In the past you may have used MS-DOS or Microsoft Disk Operating System, which was a command line interface. This form of system software required specific commands to be typed. Windows 95 is a more recent version of system software and is known as a graphical interface. This means that it uses graphics or "icons" to represent various operations. You no longer have to memorize commands; you simply point to an icon and click.

Program Software

Program software is software used to write computer programs in specific computer languages.

Application Software

Application software is any software used for specified applications such as:

·      Word Processing

·    Spreadsheet

·    Database

·    Presentation Graphics

• Communication

1.14 Generation of languages

The computers understand only the machine language. It consists of zero and one. Then came the assembly language, which is the combination of those zeros and ones. The later generations invented low-level languages like ‘C’, which is close to the natural language. Then came the high level languages, which uses highly sophisticated compilers to translate the data to the machine language.

Considering the diversity in the use of computers, programming languages with different goals have been developed. Computer's architecture has an effect on the language design.

Programming language

The first high level language that was used for scientific applications was FORTRAN and then there was ALGOL60.For business applications there was COBOL. For artificial intelligence was LISP and PROLOG a dialect of LISP. For system programming in IBM MAINFRAME computer was PL/S a dialect of PL/I. for digital BLISS, a language at a level just above assembly language.
the UNIX operating system is entirely written in 'C'. Programming languages are categorized into four bins namely imperative, functional, logic and object oriented.

Let's know the reasons for studying programming languages before introducing yourself to the programming languages. 

REASONS FOR STUDYING THE CONCEPTS OF PROGRAMMING LANGUAGES

1. Increased capacities to express ideas

2. Improved background for choosing appropriate languages

3. Increased ability to learn new languages

A short history is mentioned for some of the programming languages noted in the following table.