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Optical Disc: Optical Disc is commonly used as an external storage device in which a laser beam helps to read
data from the flat surface of the optical disc.
CD: CD or Compact Disc is a common optical disc. It is made up of lightweight plastic
material with a chemical coating on one side where data is stored.
It is inserted into a CD/DVD drive or CD/DVD writer of a CPU. In CD ROM (Compact
Disc Read Only Memory) data can only be read whereas in CD writer, data can be read
and written as well. The capacity of 120 mm standard CD is 700 MB.
DVD: DVD or Digital Versatile/Video Disc is an optical disc that looks like a CD but has
a capacity to store data up to 17.1 GB.
To read information stored in a DVD, it has to be inserted into a DVD ROM or DVD
Writer or DVD player (to copy information on a DVD, one has to use a DVD writer).
Blu-ray Disc: Blu-ray Disc can store data of up to 128 GB. It has been developed
by the Blu-ray Disc Association (BDA). It is more advanced than CDs or DVDs.
Blue-violet laser is used to read or write data on the Blu-ray disc.
Flash Memory: Flash Memory is a small-sised external storage device that is commonly used in digital
cameras, mobile phones, MP3 players, etc. It can be plugged through the USB or Fire wire port of a
computer to fetch or transfer data to a computer.
Pen/Flash Drive: It is small in size, handy and is a detachable device from which data
can be read, copied or transferred from one system to another. It is re-writable and
weighs less than 25 gm.
Nowadays, pen drives are the most commonly used external storage and data transferring device. It has an
attachment slot that can be easily inserted or attached to the computer’s USB (Universal Serial Bus) port.
Memory Stick: Memory Stick is a detachable flash memory card device that was launched
by Sony in 1998. The data stored in a memory card can be read or written with a memory
stick (typically a small box that connects via USB or some other serial connection). Memory
Stick supports memory cards of different storage capacities and helps in faster data transfer speeds.
Other Components of a Computer System
Understanding the essential parts of a computer helps us see how they work together to make the computer
function properly. Each part plays an important role in how well the computer works, from handling tasks
and storing information to connecting with other devices and adding new features. Let’s take a closer look at
these key components:
Motherboard
Motherboard is the main circuit board of a computer that lies inside the CPU,
to which all the hardware devices are connected. It is in the form of a large
multilayered printed circuit which contains connectors (sockets) for attaching
additional devices.
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