Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Students can Download Computer Applications Chapter 3 Computer Organisation Questions and Answers, Notes Pdf, Samacheer Kalvi 11th Computer Applications Book Solutions Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Samacheer Kalvi 11th Computer Applications Computer Organisation Text Book Back Questions and Answers

I. Choose The Correct Answer

Question 1.
Which of the following is said to be the brain of a computer?
(a) Input devices
(b) Output devices
(c) Memory device
(d) Microprocessor
Answer:
(d) Microprocessor

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 2.
Which of the following is not the part of a microprocessor unit?
(a) ALU
(b) Control unit
(c) Cache memory
(d) register
Answer:
(c) Cache memory

Question 3.
How many bits constitute a word?
(a) 8
(b) 16
(c) 32
(d) Determined by the processor used.
Answer:
(d) Determined by the processor used.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 4.
Which of the following device identifies the location when address is placed in the memory address register?
(a) Locator
(b) Encoder
(c) Decoder
(d) Multiplexer
Answer:
(c) Decoder

Question 5.
Which of the following is a CISC processor?
(a) Intel P6
(b) AMD K6
(c) Pentium III
(d) Pentium IV
Answer:
(c) Pentium III

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 6.
Which is the fastest memory?
(a) Hard disk
(b) Main memory
(c) Cache memory
(d) Blue-Ray dist
Answer:
(c) Cache memory

Question 7.
How many memory locations are identified by a processor with 8 bits address bus at a time?
(a) 28
(b) 1024
(c) 256
(d) 8000
Answer:
(c) 256

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 8.
What is the capacity of 12cm diameter DVD with single sided and single layer?
(a) 4.7 GB
(b) 5.5 GB
(c) 7.8GB
(d) 2.2 GB
Answer:
(a) 4.7 GB

Question 9.
What is the smallest size of data represented in a CD?
(a) Blocks
(b) Sectors
(c) Pits
(d) Tracks
Answer:
(c) Pits

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 10.
Display devices are connected to the computer through:
(a) USB port
(b) Ps/2 port
(c) SCSI port
(d) VGA connector
Answer:
(d) VGA connector

II. Short Answers

Question 1.
What are the parameters which influence the characteristics of a microprocessor?
Answer:
A Microprocessor’s performance depends on the following characteristics:

  1. Clock speed
  2. Instruction set
  3. Word size.

Question 2.
What is an instruction?
Answer:
A command which is given to a computer to perform an operation on a piece of data is called an instruction.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 3.
What is a program counter?
Answer:
The Program Counter (PC) is a special register in the CPU which always keeps the address of the next instruction to be executed.

Question 4.
What is HDMI?
Answer:
High-Definition Multimedia Interface is an audio/video interface which transfers the uncompressed video and audio data from a video controller, to a compatible computer monitor, LCD projector, digital television etc.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 5.
Which source is used to erase the content of a EPROM?
Answer:
Erasable Programmable Read Only Memory is a special type of memory which serves as a PROM, but the content can be erased using ultraviolet rays. EPROM retains its contents until it is exposed to ultraviolet light. The ultraviolet light clears its contents, making it possible to reprogram the memory.

III. Explain in Brief.

Question 1.
Differentiate Computer Organization from Computer Architecture?
Answer:
Computer Organisation:
Computer organisation deals with the hardware components of a computer system. It includes input / output devices, the central processing unit, storage and primary memory.

Computer Architecture:
Computer architecture deals with the engineering considerations involed in designing a computer.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 2.
Classify the microprocessor based on the size of the data?
Answer:
Depending on the data width, microprocessors can process instructions. The microprocessors can be classified as follows:

  1. 8-bit microprocessor
  2. 16-bit microprocessor
  3. 32-bit microprocessor
  4. 64-bit microprocessor.

Question 3.
Write down the classifications of microprocessors based on the instruction set?
Answer:
Reduced Instruction Set Computers (RISC):
RISC stands for Reduced Instruction Set Computers. They have a small set of highly optimized instructions. Complex instructions are also implemented using simpler instructions, thus reducing the size of the instruction set.
Eg: RISC processors are Intel P6, Pentium IV, AMD K6 and K7.

Complex Instruction Set Computers (CISC):
CISC stands for Complex Instruction Set Computers. They support hundreds of instructions. Computers supporting CISC can accomplish a wide variety of tasks, making them ideal for personal computers.
Eg: CISC processors are Intel 386 & 486, Pentium, Pentium II and III, and Motorola 68000.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 4.
Differentiate PROM and EPROM?
Answer:
PROM:
PROM is a memory on which data can be written only once.

EPROM:
EPROM is a memory on which ultra violet rays are used to clear its contents and making it possible to reprogram the memory.

Question 5.
Write down the interfaces and ports available in a computer?
Answer:
Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation
Serial Port:
To connect the external devices, found in old computers.

Parallel Port:
To connect the printers, found in old computers.

USB Ports:
To connect external devices like cameras, scanners, mobile phones, external hard disks and printers to the computer. USB 3.0 is the third major version of the Universal Serial Bus (USB) standard to connect computers with other electronic gadgets. USB 3.0 can transfer data up to 5 Giga byte/second. USB 3.1 and USB 3.2 are also released.

VGA Connector:
To connect a monitor or any display device like LCD projector. Audio Plugs: To connect sound speakers, microphone and headphones.

PS/2 Port:
To connect mouse and keyboard to PC.

SCSI Port:
To connect the hard disk drives and network connectors.

High Definition Multimedia Interface (HDMI):
High-Definition Multimedia Interface is an audio/video interface which transfers the uncompressed video and audio data from a video controller, to a compatible computer monitor, LCD projector, digital television etc.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 6.
Differentiate CD and DVD?
Answer:
CD:

  1. CD stands for compact Disk.
  2. CDs are made with the purpose of holding audio files as well as program files.
  3. A standard CD can store about 700 MB of data.

DVD:

  1. DVD stands for digital versatile disc.
  2. DVDs are made with the purpose of holding video files, movies, substantial amount of programs etc.
  3. A standard DVD can hold 4.7 GB of data.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 7.
How will you differentiate a flash memory and an EEPROM?
Answer:
Flash Memory:

  1. The flash memory allows data to be written or erased in blocks.
  2. Flash memory is faster in performance.

EEPROM:

  1. The EEPROM requires data to be written or erased one byte at a time.
  2. EEPROM is slower in performance.

IV. Explain in detail.

Question 1.
Explain the characteristics of a microprocessor?
Answer:
A Microprocessor’s performance depends on the following characteristics:

  1. Clock speed
  2. Instruction set
  3. Word size.

1. Clock Speed:
Every microprocessor has an internal clock that regulates the speed at which it executes instructions. The speed at which the microprocessor executes instructions is called the clock speed. Clock speed is measured in MHz (Mega Hertz) or in GHz (Giga Hertz).

2. Instruction Set:
A command which is given to a computer to perform an operation on data is called an instruction. Basic set of machine level instructions that a microprocessor is designed to execute is called as an instruction set. This instruction set carries out the following types of operations: Data transfer, Arithmetic operations, Logical operations, Control flow, Input/output.

3. Word Size:
The number of bits that can be processed by a processor in a single instruction is called its word size. Word size determines the amount of RAM that can be accessed by a microprocessor at one time and the total number of pins on the microprocessor. Total number of input and output pins in turn determines the architecture of the microprocessor.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 2.
How the read and write operations are performed by a processor? Explain?
Answer:
The read operation fetches data from memory and transfers to MDR. A single control line performs two operations like Read / Write using 1 or 0. Also, the write operation transfers data from the MDR to memory. This organisation is shown in figure.
Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation
The word in the RAM has the same size (no. of bits) as the Memory Data Register (MDR). If the processor is an 8-bit processor like Intel 8085, its MDR and the word in the RAM both have 8 bits.

If the size of the MDR is eight bits, which can be connected with a word of eight bits where the data can be stored or retrieved, the data bus has eight wires in parallel to transfer the data in any one direction which depends on whether the control is read or write. This control line is labeled as R/W, which becomes 1 meAnswer: READ operation and 0 me WRITE operation.

Figure shows the content of MDR and the Memory Word before the READ operation. Also Figure shows the content of MDR and the Memory Word after the READ operation.
Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation
Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

The read operation transfers the data (bits) from word to memory data register. The write operation transfers the data (bits) from memory data register to word.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 3.
Arrange the memory devices in ascending order based on the access time?
Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation
Answer:
Cache memory:
The cache is a very high speed, expensive piece of memory, which is used to speed up the memory retrieval process. The idea of introducing a cache is that, this extremely fast memory would store data that is frequently accessed and if possible, the data that is spatially closer to it. This helps to achieve the fast response time.

Random-access memory / main memory:
RAM is a volatile memory, which meAnswer: that the information stored in it is not permanent. As soon as the power is turned off, whatever data that resided in a RAM is lost. It allows both read and write operations.

Hard Disk:
Hard disk is a magnetic disk on which we can store computer data. In general, hard disks are less portable than floppies, although it is possible to port by removable hard disks. Two types of removable hard disks are disk packs and removable catridges.

Compact disk:
A CD or CD-ROM is made from 1.2 millimeters thick, polycarbonate plastic material. A thin layer of aluminium or gold is applied to the surface. CD data is represented as tiny indentations known as “pits”, encoded in a spiral track moulded into the top of the polycarbonate layer. The areas between pits are known as “lands”. A motor within the CD player rotates the disk. The capacity of an ordinary CD-ROM is 700MB.

Digital versatile Disc (DVD):
A DVD (Digital Versatile Disc or Digital Video Disc) is an optical disc capable of storing up to 4.7 GB of data, more than six times what a CD can hold. DVDs are often used to store movies at a better quality than with a VHS. DVDs can also have interactive menus and bonus features such as deleted scenes and commentaries. Like CDs, DVDs are read with a laser.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 4.
Explain the types of ROM?
Answer:
Read-Only memory (ROM):
Read-only memory refers to special memory in a computer with pre-recorded data at manufacturing time which cannot be modified. The stored programs that start the computer and perform diagnostics are available in ROMs. ROM stores critical programs such as the program that boots the computer.

Once the data has been written onto a ROM chip, it cannot be modified or removed and can only be read. ROM retains its contents even when the computer is turned off. So, ROM is called as a non-volatile memory.

Programmable Read-Only Memory (PROM):
Programmable read-only memory is also a non-volatile memory on which data can be written only once. Once a program has been written onto a PROM, it remains there forever. Unlike the main memory, PROMs retain their contents ‘ even when the computer is turned off.

The PROM differs from ROM. PROM is manufactured as a blank memory, whereas a ROM is programmed during the manufacturing process itself. PROM programmer or a PROM burner is used to write data to a PROM chip. The process of programming a PROM is called burning the PROM.

Erasable Programmable Read-Only Memory (EPROM): Erasable Programmable Read-Only Memory is a special type of memory which serves as a PROM, out the content can be erased , using ultraviolet rays. EPROM retains its contents until it is exposed to ultraviolet light. The ultraviolet light clears its contents, making it possible to reprogram the memory.

An EPROM differs from a PROM, PROM can be written only once and cannot be erased. EPROMs are used widely in personal computers because they enable the manufacturer to change the contents of the PROM to replace with updated versions or erase the contents before the computer is delivered.

Electrically Erasable Programmable Read-Only Memory is a special type of PROM that can be erased by exposing it to an electrical charge. Like other types of PROM, EEPROM retains its contents even when the power is turned off. Comparing with all other types of ROM, EEPROM is slower in performance.

Samacheer Kalvi 11th Computer Applications Computer Organisation Additional Questions and Answer

1. Choose The Correct Answer

Question 1.
………………….. deals with the engineering considerations involved in designing a computer.
(a) Computer organisation
(b) Computer architecture
(c) Microprocessor
(d) Registers
Answer:
(b) Computer architecture

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 2.
Microprocessor is made up of ……………………. units.
(a) 3
(b) 2
(c) 4
(d) 5
Answer:
(a) 3

Question 3.
The speed at which the microprocessor executes instructions is called:
(a) clock speed
(b) instruction set
(c) word size
(d) control flow
Answer:
(a) clock speed

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 4.
The number of bits that can be processed by a processor in a single instruction is called its:
(a) clock speed
(b) instruction set
(c) word size
(d) control flow
Answer:
(c) word size

Question 5.
……………………….. is unidirectional.
(a) Data bus
(b) Control bus
(c) Register
(d) Address bus
Answer:
(d) Address bus

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 6.
…………………… is bidirectional.
(a) Data bus
(b) Control bus
(c) Register
(d) Address bus
Answer:
(a) Data bus

Question 7.
……………………. is a volatile memory.
(a) ROM
(b) EPROM
(c) PROM
(d) RAM
Answer:
(d) RAM

Question 8.
The areas between pits are known as:
(a) sector
(b) track
(c) layer
(d) lands
Answer:
(d) lands

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 9.
The capacity of an ordinary CD-ROM is:
(a) 800 MB
(b) 700 MB
(c) 900 MB
(d) 600 MB
Answer:
(b) 700 MB

Question 10.
……………………… is the type of disc used for play station games and for playing high-definition (HD) movies.
(a) Hard disks
(b) CD
(c) DVD
(d) Blu-ray disc
Answer:
(d) Blu-ray disc

II. Short Answers

Question 1.
Define computer organisation?
Answer:
Computer organization deals with the hardware components of a computer system. It includes input/output devices, the central processing unit, storage and primary memory. It is concerned with how the various components of computer hardware operate. It also deals with how they are interconnected to implement an architectural specification.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 2.
What are the three main units of microprocessor?
Answer:
The microprocessor is made up of 3 main units. They are –
(i) Arithmetic and Logic unit (ALU):
To perform arithmetic and logical instructions based on computer instructions.

(ii) Control unit:
To control the overall operations of the computer through signals.

(iii) Registers (Internal Memory):
They are used to hold the instruction and data for the execution of the processor.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 3.
Define instruction set?
Answer:
A command which is given to a computer to perform an operation on data is called an instruction. Basic set of machine level instructions that a microprocessor is designed to execute is called as an instruction set.

Question 4.
What do you mean by word size?
Answer:
The number of bits that can be processed by a processor in a single instruction is called its word size. Word size determines the amount of RAM that can be accessed by a microprocessor. Total number Of input and output pins in turn determines the architecture of the microprocessor.

Question 5.
Define bus?
Answer:
Abus is a collection of wires used for communication between the internal components of a computer.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 6.
What is decoder?
Answer:
A decoder, a digital circuit is used to point to the specific memory location where the word can be located.

Question 7.
What is read operation?
Answer:
The read operation transfers the data (bits) from memory word to memory data register.

Question 8.
What is write operation?
Answer:
The write operation transfers the data (bits) from memory data register to word.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 9.
What criteria microprocessors are classified?
Answer:
Microprocessors are classified based on the following criteria:

  1. The width of data that can be processed.
  2. The instipction set.

Question 10.
What is USB 3.0?
Answer:
USB 3.0 is the third major version of the Universal Serial Bus (USB) standard to connect computers with other electronic gadgets. USB 3.0 can transfer data up to 5 Giga byte/second. USB 3.1 and USB 3.2 are also released.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 11.
What are the two basic types of ROM?
Answer:
There are two basic types of RAM

  1. Dynamic RAM (DRAM)
  2. Static RAM (SRAM)

Question 12.
What is Access time?
Answer:
Access time is the time delay or latency between a request to an electronic system, and the access being completed or the requested data returned.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 13.
What is a computer memory?
Answer:
Computer memory is the storage space in the computer, where data and instructions are stored. There are two types of accessing methods to access (store or retrieve) the memory. They are sequential access and random access. In sequential access, thd memory is accessed in an orderly manner from starting to end. But, in random access, any byte of memory can be accessed directly without navigating through previous bytes.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 14.
What is a system bus?
Answer:
The system bus is a bunch of wires which is the collection of address bus, data bus and control bus.

Question 15.
Differentiate static RAM and Dynamic RAM?
Answer:
Static RAM:

  1. Static RAM needs to be refreshed less often.
  2. Static RAM is more expensive.
  3. Static RAM uses transistor to store a single bit of data.
  4. Static RAM are used in cache memory.

Dynamic RAM:

  1. Dynamic RAM needs to be refreshed frequently.
  2. Dynamic RAM is less expensive.
  3. Dynamic RAM uses a separate capacitor to store each bit of data.
  4. Dynamic RAM are used in main memory.

III. Explain in Brief.

Question 1.
What is microprocessor? Draw the block diagram of microprocessor?
Answer:
The microprocessor is a programmable multipurpose silicon chip that is based on a register. It is driven by clock pulses. It accepts input as a binary data and after processing, it provides the output data as per the instructions stored in the memory.
Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 2.
Write short notes on DVD?
Answer:
A DVD (Digital Versatile Disc or Digital Video Disc) is an optical disc capable of storing up to 4.7 GB of data, more than six times what a CD can hold. DVDs are often used to store movies at a better quality. Like CDs, DVDs are read with a laser.

The disc can have one or two sides, and one or two layers of data per side; the number of sides and layers determines how much it can hold. A 12 cm diameter disc with single sided, single layer has 4.7 GB capacity, whereas the single sided, double layer has 8.5 GB capacity. The 8 cm DVD has 1.5 GB capacity. The capacity of a DVD-ROM can be visually determined by noting the number of data sides of the disc. Double-layered sides are usually gold-coloured, while single-layered sides are usually silver-coloured, like a CD.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 3.
Write short notes on Blu-ray Disc?
Answer:
Blu-Ray Disc is a high-density optical disc similar to DVD. Blu-ray is the type of disc used for PlayStation games and for playing high-definition (HD) movies. A double-layer Blu-Ray disc can store up to 50GB (gigabytes) of data. This is more than 5 times the capacity of a DVD, and above 70 times of a CD.

The format was developed to enable recording, rewriting and playback of high-definition video, as well as storing large amount of data. DVD uses a red laser to read and write data. But, Blu-ray uses a blue-violet laser to write. Hence, it is called as Blu-Ray.

Question 4.
What are the methods to access the memory? Draw the memory Hierarchy?
Answer:
Computer memory is the storage space in the computer, where data and instructions are stored. There are two types of accessing methods to access (read or write) the memory.

They are sequential access and random access. In sequential access, the memory is accessed in an orderly manner from starting to end. But, in random access, any byte of memory can be accessed directly without navigating through previous bytes.
For figure refer Page 46, Fig. No. 3.5.

Samacheer Kalvi 11th Computer Applications Solutions Chapter 3 Computer Organisation

Question 5.
List down the different types of operations in Instruction set?
Answer:
A command which is given to a computer to perform an operation on data is called an instruction. Basic set of machine level instructions that a microprocessor is designed to execute is called as an instruction set. This instruction set carries out the following types of operations:

  1. Data transfer
  2. Arithmetic operations
  3. Logical operations
  4. Control flow
  5. Input/output.

IV. Explain in detail.

Question 1.
Explain in detail the various types of storage devices?
Answer:
Secondary Storage Devices:
The secondary storage devices are used to store data that is of larger size which can be accessed later. Since the main memory is costly, the size is generally very limited in a computer. A portion of a secondary storage which can serve as an extension of the main memory and can perform its job is called as virtual memory.

Hard Disks:
Hard disk is a magnetic disk on which you can store computer data. The term hard is used to distinguish it from a soft, or floppy disk. Hard disks can store more data and are faster than floppy disks.

A hard disk, for example, can store anywhere from 10 megabytes to several gigabytes, whereas most floppies have a maximum storage capacity of 1.4 megabytes. In general, hard disks are less portable than floppies, although it is possible to port by removable hard disks. There are two types of removable hard disks: disk packs and removable cartridges.

Compact Disc (CD):
A CD or CD-ROM is made from 1.2 millimeters thick, polycarbonate plastic material. A thin layer of aluminum or gold is applied to the surface. CD data is represented as tiny indentations known as “pits”, encoded in a spiral track moulded into the top of the polycarbonate layer. The areas between pits dre known as “lands”. A motor within the CD player rotates the disk. The capacity of an ordinary CD-ROM is 700MB.

Digital Versatile Disc (DVD):
A DVD (Digital Versatile Disc or Digital Video Disc) is an optical disc capable of storing up to 4.7 GB of data, more than six times what a CD can hold. DVDs are often used to store movies at a better quality than with a VHS. DVDs can also have interactive menus and bqpus features such as deleted scenes and commentaries. Like CDs, DVDs are read with a laser.

The disc can have one or two sides, and one or two layers of data per side; the number of sides and layers determines how much it can hold. A 12 cm diameter disc with single sided, single layer has 4.7 GB capacity, whereas the single sided, double layer has 8.5 GB capacity.

The 8 cm DVD has 1.5 GB capacity. The capacity of a DVD-ROM can be visually determined by noting the number of data sides of the disc. Double-layered sides are usually gold-coloured, while single-layered sides are usually silver-coloured, like a CD.

Flash Memory Devices:
Flash memory is an electronic (solid-state) non-volatile computer storage medium that can be electrically erased and reprogrammed. They are either EEPROM or EPROM. Examples for Flash memories are pendrives, memory cards etc.

Flash memories can be used in personal computers, Personal Digital Assistants (PDA), digital audio players, digital cameras and mobile phones. Flash memory offers fast access times. The time taken to read or write a character in memory is called access time. The capacity of the flash memories vary from 1 Gigabytes (GB) to 2 Terabytes (TB).

Blu-Ray Disc:
Blu-Ray Disc is a high-density optical disc format similar to DVD. Blu-ray is the type of disc used for PlayStation games and for playing high-definition (HD) movies. In the past, there were other standards for such movies. A double-layer Blu-Ray disc can store up to 50GB (gigabytes) of data.

This is more than 5 times the capacity of a DVD, and above 70 times of a CD. The format was developed to enable recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data. DVD uses a red laser to read and write data. But, Blu-ray uses a blue-violet laser to write. Hence, it is called as Blu-Ray.