Chapter 1 - Introduction to Computer

Added on - 10 Aug 2021

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Chapter One
Introduction to Computer

ComputerA computer is an electronic device, operating under the control of instructions stored
in its own memory that can accept data (input), process the data according to specified
rules, produce information (output), and store the information for future use1.

Functionalities of a computer2Any digital computer carries out five functions in gross terms:

Computer ComponentsAny kind of computers consists ofHARDWAREANDSOFTWARE.

Computer hardware is the collection of physical elements that constitutes a computer
system. Computer hardware refers to the physical parts or components of a computer
such as the monitor, mouse, keyboard, computer data storage, hard drive disk (HDD),
system unit (graphic cards, sound cards, memory, motherboard and chips), etc. all of
which are physical objects that can be touched.3
1Vermaat, Misty E. Microsoft Office 2013 Introductory. Cengage Learning, p.IT3. 20142
Input Devices
Input device is any peripheral (piece of computer hardware equipment to provide data
and control signals to an information processing system such as a computer or other
information appliance.
Input device Translate data fromformthat humans understand to one that the computer
can work with. Most common are keyboard and mouse

Example of Input Devices:-
1.Keyboard2.Mouse (pointing device)3.Microphone
4.Touch screen5.Scanner6.Webcam
7.Touchpads8.MIDI keyboard9.
10.Graphics Tablets11.Cameras12.Pen Input
13.Video Capture Hardware14.Microphone15.Trackballs
16.Barcode reader17.Digital camera18.Joystick
19.Gamepad20.Electronic Whiteboard21.

Note:The most common use keyboard is the QWERTY keyboard. Generally standard Keyboard
has 104 keys.

Central Processing Unit (CPU)
A CPU is brain of a computer. It is responsible for all functions and processes.
Regarding computing power, the CPU is the most important element of a computer

The CPU is comprised of three main parts :
* ArithmeticLogicUnit (ALU): Executes all arithmetic and logical operations.
Arithmetic calculations like as addition, subtraction, multiplication and division.
Logical operation like compare numbers, letters, or special characters
*ControlUnit (CU):controls and co-ordinates computer components.
1.Read the code for the next instruction to be executed.
2.Increment the program counter so it points to the next instruction.
3.Read whatever data the instruction requires from cells in memory.
4.Provide the necessary data to an ALU or register.
5.If the instruction requires an ALU or specialized hardware to complete, instruct
the hardware to perform the requested operation.
*Registers:Stores the data that is to be executed next, "very fast storage area".

Primary Memory:-
1.RAM: Random Access Memory (RAM) is a memory scheme within the computer
system responsible for storing data on a temporary basis, so that it can be promptly
accessed by the processor as and when needed. It is volatile in nature, which means
that data will be erased once supply to the storage device is turned off. RAM stores
data randomly and the processor accesses these data randomly from the RAM
storage. RAM is considered "random access" because you can access any memory
cell directly if you know the row and column that intersect at that cell.
2.ROM(Read Only Memory): ROM is a permanent form of storage. ROM stays
active regardless of whether power supply to it is turned on or off. ROM devices
do not allow data stored on them to be modified.

Secondary Memory:-
Stores data and programs permanently :its retained after the power is turned off

1. Hard drive (HD): A hard disk is part of a unit, often called a "disk drive," "hard drive," or "hard
disk drive," that store and provides relatively quick access to large amounts of data on an
electromagnetically charged surface or set of surfaces.
2. Optical Disk: an optical disc drive (ODD) is a disk drive that uses laser light as part of the process
of reading or writing data to or from optical discs. Some drives can only read from discs, but recent
drives are commonly both readers and recorders, also called burners or writers. Compact discs,
DVDs, and Blu-ray discs are common types of optical media which can be read and recorded by
such drives. Optical drive is the generic name; drives are usually described as "CD" "DVD", or
"Bluray", followed by "drive", "writer", etc. There are three main types of optical media: CD,
DVD, and Blu-ray disc. CDs can store up to 700 megabytes (MB) of data and DVDs can store up
to 8.4 GB of data. Blu-ray discs, which are the newest type of optical media, can store up to 50
GB of data. This storage capacity is a clear advantage over the floppy disk storage media (a
magnetic media), which only has a capacity of 1.44 MB.
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