In this lesson we present an overview of the basic design of a computer system: how the different parts of a computer system are organized and various operations performed to perform a specific task. You would have observed that instructions have to be fed into the computer in a systematic order to perform a specific task. Computer components are divided into two major categories, namely, hardware and software. In this lesson we will discuss about hardware, i.e., the machine itself and its connected devices such as monitor, keyboard, mouse etc., as well as software that makes use of hardware for performing various functions.
OBJECTIVES
After seen this video you would be able to:
- explain basic organization of computer system
- explain different types of input and output devices
- define Software and its classification
- distinguish between system software and application software
- describe computer language and its classification
Basics of Computer Nios Class 10th and 12th (Part -1st)
WHAT IS A COMPUTER?
Computer is a device that transforms data into meaningful information. Data can be anything like marks obtained by you in various subjects. It can also be name, age, sex, weight, height, etc. of all the students in a class.
Computer can also be defined in terms of functions it can perform. A computer can (i) accept data, (ii) store data, (iii) process data as desired, and (iv) retrieve the stored data as and when required and (v) print the result in desired format.
The major characteristics of a computer are high speed, accuracy, diligence, versatility and storage.
Computer Organisation
- Input: this is the process of entering data and programs into the computer system.
- Control Unit (CU): The process of input, output, processing and storage is performed under the supervision of a unit called ‘Control Unit’. It decides when to start receiving data, when to stop it, where to store data, etc. It takes care of step -by-step processing of all operations in side the computer.
- Memory Unit: Computer is used to store data and instructions.
- Arithmetic Logic Unit (ALU): The major operations performed by the ALU are addition, subtraction, multiplication, division, logic and comparison.
- Output: This is the process of producing results from the data for getting useful information
PERIPHERAL DEVICES
INPUT DEVICES
Input devices accept data and instructions from the user. Following are the examples of various input devices, which are connected to the computer for this purpose.
Keyboard
A keyboard is the most common input device. Several kinds of keyboards are available, but they resemble each other with minor variations. The keyboard in most common use is the QWERTY board. Generally standard keyboard has 104 keys. In these keyboards, the cursor control keys are duplicated to allow easier use of the numeric pad.
Mouse
A mouse is an electro-mechanical, hand-held device It is used as a pointer. It can perform functions like selecting menu commands, moving icons, resizing windows, starting programs, and choosing options. The most common mouse uses an internal, magnetically coated ball, to detect the movement of the mouse across a flat surface, usually a desktop. Now a days Optical or laser mouse is used to detect the movement.
Light pen
An input device that utilizes a light-sensitive detector to select objects on a display screen. A light pen is similar to a mouse except that with a light pen you can move the pointer and select objects on the display screen by directly pointing to the objects with the pen.
Optical Scanner
These devices are used for automatic data collection. The devices of this category completely eliminate manual input of data. For example, the bar-code reader is actually just a special type of image scanner. An image scanner translates printed images into an electronic format that can be stored in a computer’s memory, and with the right kind of software, one can alter a stored image.
Touch Screen
Touch panel displays and pads are now being offered as alternatives to keyboard. Here the input can be given through the computer screen, that accepts the input through monitor; users touch electronic buttons displayed on the screen or they may use light pen.
Microphone
Microphone is an input device, which takes voice as input. The voice communication is more error-prone than information through keyboard. There are two types of microphones available
1. Desktop Microphone
2. Hand held Microphone
Track Ball
Trackball, a pointing device, is a mouse lying on its back To move the pointer, you rotate the ball with your thumb, your fingers, or the palm of your hand. There are usually one to three buttons next to the ball, which you use just like mouse buttons
Basics of Computer (Part -3)
OUTPUT DEVICES
Output devices return processed data that is information, back to the user. Some of the commonly used output devices are:
Monitor
Out of all the output devices, monitor is perhaps the most important output device because people interact with this device most intensively than others. Computer information is displayed, visually with a video adapter card and monitor. Information processed within the CPU, that needs to be visually displayed, is sent to video adapter.
Two basic types of monitors are used with microcomputers, which are as follows:
- CRT
- LCD
Printer
After a document is created on the computer, it can be sent to a printer for a hard copy (printout). Some printers offer special features such as colored and large page formats. Some of the most commonly used printers are:
- Laser Printer
- Ink Jet Printer
- Dot Matrix Printer
- Line Printer
Plotter
A plotter is a special kind of output device that, like a printer,produces images on paper, but does so in a different way. Plotters are designed to produce large drawings or images, such as construction plans for buildings or blueprints for mechanical objects. A plotter can be connected to the port normally used by a printer
Plotters usually come in two designs
- Flat Bed:- Plotters of small size to be kept on table with restriction of paper size.
- Drum:- These plotters are of big size using rolls of paper of unlimited length.
Speaker
Speakers are another type of output device, whichallow you to listen to voice like music, and conversation with people.
Basics of Computer (Part – 3rd)
SOFTWARE
As you are aware, computer cannot do anything on its own. It is the user who instructs computer; what to do, how to do and when to do. In order to perform any task, you have to give a set of instructions in a particular sequence to the computer. These sets of instructions are called Programs. Software refers to a set of programs that makes the hardware perform a particular set of tasks in particular order.
System Software
When you switch on the computer the programs stored in ROM are executed which activates different units of your computer and makes it ready for you to work on it. This set of programs can be called system software.
System softwares are sets of programs, responsible for running the computer, controlling various operations of computer systems and management of computer resources. Operating System (OS) falls under this category.
Application Software
Application software is a set of programs, which are written to perform specific tasks, for example: An application package for managing library known as library information system is used to manage information of library such as: keeping book details, account holder details, book issue details, book return details etc. Another application package for managing student details is called student’s information system, manages student’s roll no, name, parents name, address, class, section, processing of examination results etc. Application software can be broadly classified into two types:
(a) Generalized packages
(b) Customized packages
Generalized Packages
These are user friendly softwares written to cater to user’s very general needs such as preparing documents, drawing pictures, database to manage data/information, preparing presentations, play games etc.
Customized Packages
These are the applications that are customized (or developed) to meet the specific requirements of an organization/institution. For Example: Student information details, Payroll packages, inventory control etc.
COMPUTER LANGUAGES
Languages are a means of communication. Normally people interact with each other through a language. On the same pattern, communication with computers is carried out through a language. This language is understood both by user and the machine. Just as every language like English, Hindi has its grammatical rules; every computer language is bound by rules known as SYNTAX of that language. The user is bound by that syntax while communicating with the computer system.
- Low Level Language: – The term low level means closeness to the way in which machine understand. The low level languages are:
a. Machine Language: This is the language (in the form of 0’s and 1’s, called binary numbers) understood directly by the computer. It is machine dependent.
b. Assembly Language: This is the language where the machine codes comprising of 0’s and 1’s are substituted by symbolic codes (called mnemonics) to improve their understanding. It is the first step to improve programming structure.
2. High Level Language :- Various high level languages are given below:
BASIC (Beginners All Purpose Symbolic Instruction Code): It is widely used, easy to learn general purpose language. Mainly used in microcomputers in earlier days.
COBOL (Common Business Oriented language): A standardized language used for commercial applications.
FORTRAN (Formula Translation): Developed for solving mathematical and scientific problems. One of the most popular languages among scientific community.
C: Structured Programming Language used for all purpose such as scientific application, commercial application, developing games etc.
C++: Popular object oriented programming language, used for general purpose.
COMPILER AND ASSEMBLER
As you know that High Level language is machine independent and assembly language though it is machine dependent yet mnemonics that are being used to represent instructions are not directly understandable by machine. Hence to make the machine understand the instructions provided by both the languages, Compiler and Assembler are required to convert these instructions into machine language.
The program written by the programmer in high level language is called source program and the program generated by the compiler after translation is called as object program.