Class IX Chapter 1

Class IX

Chapter 1

The Computer System

II. Descriptive Type Questions

      A.      Very short answer questions:

                                 i.            Printer

                               ii.            Bar Code Reader

                              iii.            Control Unit

                             iv.            Digital camera

                               v.            Webcam, Microphone and speaker

      B.      Short answer question:

                                 i.            Install printer’s drivers

                               ii.            Kilobyte < megabyte < gigabyte < terabyte.

                              iii.            Hard disc , DVD, Blu-ray disc and Pen drive

                             iv.             

RAM ( Random Access Memory)	ROM ( Read Only Memory)
It is volatile in nature.	It is non – volatile in nature.
It is a read – write memory.	It is a read only memory.

                               v.             Compiler is a translator program that generates and executes a low- level language program from a high – level language program at once where as Interpreter is a translator program that translates and executes a low – level language program from a high – level language program language line by line.

           C.      Long answer question:

                                 i.            The tree parts of a computer system are:

a. Input unit – An input unit takes the input and converts it into binary form so that it can be understood by the computer. The computer input consists of data and instructions.

b.CPU – The central processing unit is the brain of any computer systems. It consists of a processing unit and a storage unit.

c. Output Unit – The output unit comprises the output devices attached to a computer. Output devices such as VDU, printer, plotter, and speaker convey information from the computer to the user.

·         Diagram is available at Page no.  – 16 ( fig 1.1)

                               ii.            Input unit comprises the input devices attached to a computer. Input devices accept input from the user and convert it into a form that can be understood by the computer ( i.e. binary form).

a. Keyboard – A keyboard is used for entering data directly into a computer.

b.Mouse – A mouse is a pointing device used for moving a pointer on a  computer monitor.

c.  Light pen – A light pen is a pointing device that can be used for selecting an option by simply pointing at it on a computer screen or for drawing figures directly on the screen.

d.Trackball – A trackball has a ball that can be rotated in different directions to move the pointer on the screen.

e.Joystick – A joystick consists of a vertical stick that can be moved to control on –screen objects. It is used to play computer games. Although a keyboard can also be used for this, a joystick provides better control.

                              iii.            Output Unit -  The output unit comprises the output devices attached to a computer. Output devices such as VDU, printer, plotter, and speaker convey information from the computer to the user.

a. Visual Display Unit (VDU) – The VDU or monitor resembles a television screen. It displays both text and graphic images. The display can be either black and white or colored, depending on the type.

b.Printer – A printer outputs the information displayed on the computer screen onto paper. The output produced on paper is called hardcopy. Printers can be divided into two categories : impact and non – impact.

c. Speaker – A speaker gives sound output from a computer. It converts an alternating electrical current into sound. It can output music as well as spoken words. Some speakers are built into the computer and some  are  placed outside.

                             iv.            Auxiliary memory is a bulk storage memory which is non  volatile in nature. It has larger storing capacity than the main memory.  Secondary storage media can be broadly categorized into : magnetic and optical.

a. Magnetic Media – Magnetic discs are called hard discs or floppy discs, depending on the flexibility of the material from which they are made.

b.Optical media – compact disc read – only memory (CD – ROM) , digital versatile disc (DVD) and Blu- ray disc are example of optical media.

                               v.            System software is a set of one or more programs that are basically designed to control the operation of a computer system.

a. Operating system – An operating system is the master control program that runs a computer. It controls the flow of signals from the CPU to various parts of the computer.

b.Device Driver – A device driver is a program that acts as an interface between a device and the user or the operating system.

c. Language processor – The language processor converts any programming language into machine language so that the computer can understand and vice versa. These translators can be classified as ass4embler, compiler, and interpreter.