Computer Science XI

Hardware and Software

Introduction A computer system has two major components, hardware and software. In practice, the term hardware refers to all the physical items associated with a computer system. Software is a set of instructions, which enables the hardware to perform a specific task. 1

Computer Hardware A computer is a machine that can be programmed to accept data (input), and process it into useful information (output). It also stores data for later reuse (storage). The processing is performed by the hardware. The computer hardware responsible for computing are mainly classified as follows:
Main memory
Input Devices CPU
Secondary Storage
Output Devices
  Input devices allows the user to enter the program and data and send it to the processing unit. The common input devices are keyboard, mouse and scanners.

The Processor, more formally known as the central processing unit (CPU), has the electronic circuitry that manipulates input data into the information as required. The central processing unit actually executes computer instructions.

Memory from which the CPU fetches the instructions and data is called main memory. It is also called as primary memory and is volatile in nature.

Output devices show the processed data – information – the result of processing. The devices are normally a monitor and printers.

Storage usually means secondary storage, which stores data and programs. Here the data and programs are permanently stored for future use. The hardware devices attached to the computer are called peripheral equipment. Peripheral equipment includes all input, output and secondary storage devices.

  Computer Software Software refers to a program that makes the computer to do something meaningful. It is the planned, step-by-step instructions required to turn data into information. Software can be classified into two categories: System Software and Application Software.

System software consists of general programs written for a computer. These programs provide the environment to run the application programs. System software comprises programs, which interact with the hardware at a very basic level. They are the basic necessity of a computer system for its proper functioning. System software serves as the interface between hardware and the user. The operating system, compilers and utility programs are examples of system software.

 The most important type of system software is the operating system. An operating system is an integrated set of specialized programs that is used to manage the overall operations of a computer. It acts like an interface between the user, computer hardware and software. Every computer must have an operating system to run other programs. DOS (Disk Operating System), Unix, Linux and Windows are some of the common operating systems. The compiler software translates the source program (user written program) into an object program (binary form). Specific compilers are available for computer programming languages like FORTRAN, COBOL, C, C++ etc. The utility programs support the computer for specific tasks like file copying, sorting, linking a object program, etc. Source Program

An Application Software consists of programs designed to solve a user problem. It is used to accomplish specific tasks rather than just managing a computer system. Application software are inturn, controlled by system software which manages hardware devices. Some typical examples are : railway reservation system, game programs, word processing software, weather forecasting programs. Among the application software some are packaged for specific tasks.

The commonly used Application Software packages are word processor, spread sheet, database management system and graphics. One of the most commonly used software package is word processing software. Anyone who has used a computer as a word processor knows that it is far more than a fancy typewriter. The great advantage of word processing over a typewriter is that you can make changes without retyping the entire document. The entire writing process is transformed by this modern word processing software. This software lets you create, edit, format, store and print text and graphics. Some of the commonly used word processors are Microsoft Word, WordStar, WordPerfect, etc. Spreadsheet software packages allow the user to manipulate numbers. Repetitive numeric calculations, use of related formulae and creation of graphics and charts are some of the basic tools.

This capability lets business people try different combinations of numbers and obtain the results quickly. Lotus1-2-3, Excel, etc. are some of the famous spreadsheet applications. A database management system is a collection of programs that enable to store, modify and extract information from a database. A database organizes the information internally. Computerized banking system, Automated Teller Machine, Airlines and Railway reservation system etc., are some of the database applications. Type of Software Functions Examples Word Processors All personal computers are loaded with word processing software which has the same function as a typewriter for writing letters, preparing reports and printing. Microsoft Word, Word Perfect, Word Star. Spreadsheet A table containing text and figures, which is used to Calculations and draw charts. Microsoft Excel, Lotus 1-2-3. Database Management System Used for storing, retrieval and Manipulation of Information Microsoft Access, Oracle.

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