Computer – Storage and Memory Devices (4 – L1) – satei4u

Computer – Storage and Memory Devices (4 – L1)

What is Data?
Data is a raw fact and figures. It consists of words, numbers, dates, images, sounds, etc, without any context.

What is Information?
When data is collected and put through in some process then the result is called Information.

A computer is an electronic device and can only understand the ON and OFF states like that of a switch. These two states are represented by the digits 1 (ON) and 0 (OFF), 0 and 1 are called binary digits. A binary number is formed by a combination of binary digits.

A computer stores data in the form of binary numbers. All the data, like words, images, sound, etc., have to be converted to binary numbers.

BIT is the smallest unit of data. It is represented by either 0 or 1. For example, 1101 is a binary number and is 4 bits long.

Byte is a group of 8 bits, It is the standard unit of storage in a computer. For example, 1011 0101 is a byte and can represent data like text, image, or sound in a computer.

Relationship between units of measurement of data
8 bits = 1 byte
1024 bytes = 1 kilobyte (1 KB)
1024 KB = 1 megabyte (1 MB)
1024 MB = 1 gigabyte (1 GB)
1024 GB = 1 terabyte (1 TB)

What is Storage device?
A storage device for a computer helps the user to store and safely access the file and application again in the future on a computer device. Knowing and learning about these computer storage devices is important as it acts as a core component of the system. Just as our brain stores information, a computer stores games, songs, pictures, etc, in storage devices.

There are two types of Storage devices as follows:
1. Primary Storage / Internal Storage
2. Secondary Storage / External Storage

Primary Storage:
This type of memory is also known as Internal Memory or Main Memory. There are two types of primary storage are RAM and ROM.

1. RAM (Random Access Memory) is a primary storage device of the computer. It stores data temporarily for quick access by the CPU. Once the computer is switched off, all the data that resides in it is lost. It is also called a Volatile Memory.

2. ROM (Read Only Memory) is a primary storage device of the computer. It contains instructions that are essential for a computer to operate. These instructions are stored permanently at the time of manufacturing and cannot be changed. These instructions can only be read by a computer.

Secondary Storage:
It is also called an external memory of the computer. It is located inside the computer. It is used to store large amounts of information permanently unless one deletes it. ex: Hard Disk, Flash Memory (Pen Drive), CD-ROM, DVD, Magnetic Disk Tapes.

Which of these devices has the highest storage capacity?
The storage capacity of the hard disk is almost a thousand times that of the RAM.

Why does a computer even need RAM if its capacity is so less?
The RAM is situated very close to the CPU, so the time taken by the CPU to access information from the RAM to perform a task is much less compared to the time taken to access information from the hard disk.

Some external storage devices

1. The compact disk or CD is a circular, flat piece of plastic which has a shiny surface on one side. You can store songs, pictures, games and other data on it. It can store up to 700 MB of data. Due to its compact size. It can be easily carried from one place to another. You need a CD drive in the computer to play a CD.
2. The digital versatile or DVD is a storage device that looks like a CD but can store six times more data than a CD, which is up to 17 GB of data.
3. A pen drive is a storage device that is easy to carry around because of its size. It can be inserted into a computer using a USB port. It allows you to store and transfer movies, songs, pictures, etc., to and from a computer quickly. Pen drives come with varying capacities ranging from 1 GB to 1 TB.

2. Write the most appropiate storage device for each of the tasks listed in the table.

TaskStorage Device
1. Storing games that run on the computerCompact Disk (CD)
2. Transferring a greeting card made using the computer at home to a computer at schoolPen Drive (Flash Drive) or CD
3. Storing movies to watch on some other computerPen Drive(Flash Drive)
4. Storing the work done on a computerHard Disc

3. State whether the following statements are True or False.

(a) The total number of books in a library is an example of information. [False]

(b) A computer stores data in the form of binary numbers. [True]

(c) Not all computers have a primary memory. [False]

(d) The CPU can obtain information from the hard disk faster than the main memory. [False]

(e) Files are saved on the hard disk. [True]

(f) Hard Disks and CDs are secondary storage devices. [False]

4. Fill in the blanks:

(a) Words, numbers and images without context are called. _____________________ (Data)

(b) A byte is a group of ________ bits. (8)

(c) The _________ storage device stores information even if the computer is switched odd. (Secondary)

(d) A pen drive can be easily connected to the computer using a _________________ (USB Port)

(e) The CPU works faster with the ________ than the hard disk. (Primary storage device)