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Study Material Class- IV Chapter 1 - STORAGE AND MEMORY DEVICE

COMPUTER

Computer is an electronic device that processes raw with the help of a program and produces meaningful information. These functions are performed in a cycle called input, process , output (IPO).

DATA PROCESSING INFORMATION

Collection, checking, By computer storing data Processed and organised preparation of raw data . for future usage . data.

Data

Raw facts that have been collected but not organised are known as data.

Information

When data is organised in a useful way it is called information.

Computer memory is measured in terms of . One is capable of holding one character. Each information is represented within the computer memory using binary digits 0 and 1 (a ). Binary 0 represents OFF and 1 represents ON. 1 BIT = 0 OR 1

1 NIBBLE = 4 1 BYTE = 8 BITS

1 KILOBYTE (KB) = 1024 BYTES

1 (MB) = 1024 KB

1 (GB) = 1024 MB

1 TERABYTE (TB) =1024 GB TYPES OF COMPUTER MEMORY

INTERNAL/PRIMARY/TEMPORARY EXTERNAL/SECONDARY/PERMANENT

ROM RAM HARD DISK , CD , DVD

PRIMARY MEMORY

It is the main memory of the computer that stores data and instructions for processing. It is interval memory that is continuously overwritten with new data and programs for quick access. It communicates directly with the CPU.

There are two types of primary memory –

1.RAM

2.ROM

RAM (RANDOM ACCESS MEMORY)

RAM stores the data and programs that are currently being used by the computer for quick access by the computer. It is a .

ROM (READ ONLY MEMORY)

ROM stores startup instructions for the computer system. It is non- volatile memory (The contents are not lost when you turn off the computer).

SECONDARY MEMORY

Sometimes we require to store a large amount of data permanently. For this purpose, we use external/secondary memory or storage devices. More and more storage devices can be used to store unlimited of data.

STORAGE DEVICES

Storage devices provide a location where data can be stored when it is not being processed. Some storages devices are – Hard Disk, Pen drive, CD, DVD, Blu-Ray Disc.

Hard Disk

It is a high capacity storage device that is fixed inside the computer cabinet ad contains all the and data. These days external Hard Disk are also available in the market to transfer bulk amount of data.

Portable Storage

Besides Hard Disk (except external hard disk) or fixed disk, all the other storage devices are portable in which you can carry data and programs anywhere.

CD ()

A compact disc is a portable storage device and commonly known as CD. It is an media. We can also erase and rewrite on a CD using a CD Writer on a re-writable CD.

DVD (Digital Versatile Disc)

DVD stands for Digital Versatile Disc. It is also called Digital Video Disc. Initially it was used to store video files only. It is similar to CD in shape and size but has a greater capacity to store a large amount of data.

USB Flash Drive

It is popularly known as pen drive. It is a device used for copying and moving data from one computer to another.

EXERCISE

1. Fill in the blanks : a. Raw facts that have been collected but not organised are known as ______. b. Computer memory is measured in terms of ______. . A combination of 8 bits makes a ______. d. Primary memory is of ______types ______and______. e. ______devices store a large amount of data permanently. 2. Write ‘True’ or ‘False’ : a. Computer is an electronic device. b. Organised data in useful way is called information. c. The storage devices are the secondary memory. d. RAM stores the data permanently. e. remains on the hard disk only. 3. Choose the correct option : a. CDs, and pen drives are ______storage devices. i. Permanent ii. Temporary iii. Neutral b. Pen drive is also known as ______drive. i. CD ii. USB Flash iii. DVD c. One byte is capable of holding ______character. i. four ii. two iii. one d. RAM and ROM are ______memory. i. Secondary ii. Primary iii. Third e. Secondary memory is ______memory. i. Internal ii. External iii. Hybrid

ANSWERS - 1. (a) data (b) bytes (c) byte (d) two, RAM, ROM (e) storage

2. (a) True (b) True (c) True (d) False (e) False

3. (a) permanent (b) USB Flash (c) one (d) Primary (e) External

ACTIVITY

1. Open MS Word and type the names of various Input and Output devices with their uses.(eg: Keyboard for typing- ) 2. Identify different types of storage devices that you have seen.

(Kindly write these Qus/Ans in your new computer notebook)

Answer the following questions :

Que1- What is a computer ?

Ans- Computer is an electronic device that processes raw data with the help of a program.

Que2- What are the different types of memory ?

Ans- There are two types of memory-

1. Primary/ Internal/ Temporary Memory- It is the main memory of the computer that stores data and information. 2. Secondary/ External/ Permanent Memory- For storing large amount of data permanently.

Que3- Define data and information ?

Ans- Data- Raw facts that have been collected but not organised are known as data.

Information- When data is organised in a useful way it is called information.

Que4- Explain the working of a computer system ?

Ans- Computer works on IPO Input Processing Output cycle. INPUT PROCESS OUTPUT

Que5- What are the types of primary memory ?

Ans- These are two types of primary memory –

1. RAM(Random Access Memory)- It stores the data and programs by computer. It is a volatile memory.

2. ROM(Read Only Memory) – It stores startup instructions for booting the computer system. It is a non-volatile memory.