NCERT Solution Class 11 Computer Science Chapter 1 – Computer System

To make a computer functional operating system is required. The two services of primary services:

1) Operating system provides services for building and running the application.

2) Operating system provide user interface to the user for enable interaction between computer and  user.

 

Computer understands only machine level language (0 and 1). High level language is a simple English type language written in some symmetric format. To convert high level language into machine language there is need of compiler which can be understood by computer.

 

We know that computer readable language is machine language. So there is no need to convert machine language whereas Source codes are written in high level language. So there is need to convert it into machine language first. Hence, the execution time of machine language is less than source code.

 

 RAM (random access memory) is used for quickly accessing a data. RAM is a temporary storage memory and it stores the active using data. Whereas ROM is a read only memory and it is a permanent storage device. Data in RAM is erased when power goes off whereas in ROM data remain as it is.

 

INPUT UNIT :

Input unit has following function:

• Input unit takes a data instruction from the user for further processing.

• We know that computer understand machine language. Input unit converts the data to the machine language (machine readable form)

They are various types of input devices are available like keyboard, scanner, mouse, touch screen devices, etc.

CENTRAL PROCESSING UNIT:

CPU i.e.  Central processing unit is responsible for performing all tasks of computer. CPU is like a heart of computer.CPU consists of 3 units:

• Primary memory

• Control unit

• Arithmetic logic unit

ALU:

Arithmetic and logical unit responsible for performing all arithmetic operation like addition, subtraction, multiplication and division .It also responsible for conduct merging, sorting like all sorting techniques .All the calculations of the data perform by ALU.

Control unit:

Control unit is used to control the signals. Control unit receives the instruction, data, and information from input devices and converts it into control signals.

Primary memory:

There are two types of primary memory

• RAM

• ROM

RAM:

• RAM means random access memory.

• It is a volatile storage.

• The data stored in RAM is temporary.

• RAM stores the data of active tasks.

 ROM :

• ROM mans read only memory.

• The data stored in ROM is permanent.

• It cannot be erased during the power cut off.

• It is a non volatile memory.

OUTPUT UNIT:

An output device is one of the components of a computer. output devices are responsible to convert machine code into the human readable form. Monitor, printer etc. are output devices.  The output given by the computer can be in any type like text, graphics, audio, video etc

 

 

 

 

 Secondary memory provides a large storage facility as well as it is very cheap .There is a need of secondary storage because it is a permanent storage device. Unlike ROM and RAM secondary memory doesn’t have limited storage.

 

Component of a computer communicate with each other with the help of system bus. System bus provides the facility to transfer the data as well as memory address between one component to another.

 

To transfer the data, address, control signal between the computers there is a need for a system bus. With the help of system bus components of a computer can communicate with each other. Data bus is bidirectional because of the two-way transfer process. IT transfers the data among CPU,memory and other peripheral devices. Address bus is unidirectional because whenever the data written in the memory, the CPU places the data on the data bus. After that the address bus provides a specific address to   write the data.

 

Different types of data while browsing the Internet:

Structured: the data which is stored in most organized way is known as structured data

Unstructured: the data which is not stored in organized way is known as unstructured data

Semi structured: the data lies in between the structured and unstructured data is known as semi structured data

 

a) Compiler – Programming tool

b) Assembler – Programming tool

c) Ubuntu – System

d) Text editor – Application

 

 

 

a) To output audio – Speaker

b) To enter textual data – Keyboard

c) To make hard copy of a text file – Printer

d) To display the data or information – Monitor

e) To enter audio-based command – Mic

f) To build 3D models – 3D Printer

g) To assist a visually-impaired individual in entering data – Braille keyboards