WHAT IS COMPUTER?
A computer is an electronic, data processing device
that
Receive the data; that we feed into it (INPUT)
Process the data; according to our instructions
(PROCESSING)
Give the result; (OUTPUT)
Store the data, inside it (MEMORY).
DEFINITION OF COMPUTER
Computer is an automatic electronic data processing
device, which can process the data under given commands, ability to remember
information and also give the result. Computer accept the data process it
generate the result (give out put) and able to store it. Computer is an
electronic machine can calculate a specific result according to our given
instructions. According to above definitions of computer it is observed that
computer cannot perform any thing with out any program/software and programmers
/soft wares are made human begins. So computer cannot perform any thing with
out instruction on user. It only can dependent upon user, which type of command
user can apply. Some advance computers like robots perform some thing without
any command perform by any human being, but these type of computer has come
special type of software which technology calls artificial intelligence. A I is
such thing in which computer observe thing and than perform some things
according to these observed, actually the software has ability to perform any
thing and decide the which thing can be performed when any event occur. So we
say hat computer perform any thing onto the verbal instructions of user.
COMPUTER SYSTEM
A collection reference to all interconnected
computing hardware, including processor, storage devices, input/output devices
and communication equipments. Complete collection of computer components i.e.
Hardware, Software, Peripherals, Power supplies and Communication links; making
up a single computer system.
Hardware
The physical parts of the computer are collectively
called its hardware. All the computer mechanism and parts are called the
computer hardware e.g. Keyboard, motherboard, mouse, modem, monitor, printer
etc.
Software
Program of the computer is called software. All the
instruction and data are called computer software. Without the computer
software the computer hardware is unable to do anything. Computer software
makes the computer hardware alive. Operating system is also software, which is
a translator between computer and computer user.
Peripherals
The keyboard and the printer are attached to the
CPU at its periphery (Edges), so they are called peripherals. The Input/Output
(I/O) devices are also called peripherals.
Power Supplies
All the power which supply inside the computer
devices are supplied by the power supply external power cable attached with
power supply and then it change it according to different and then supply it to
devices. So power supply is the controller of the power inside the computer.
Communication Links
Communication links are devices used in
communication system of interconnected computers, telephone or other
communications devices that can communicate with one another and share
applications and data e.g. Modem, LAN Card etc.
PARTS OF THE COMPUTER
There are three parts of the computer regarding
hardware.
(1) Input (2) Output (3) CPU
INPUT
It means whatever information (Data) we put in
(feed into) the computer for processing is called input. Input include two main
things
The data (row facts and figures) that we feed into
the computer.
The instructions that we give in regard to the
data.
Users basically use input devices. The data is
given to the computer by some devices i.e. Keyboard, Mouse, Scanner, Mike,
Pads, Camera, Laser pen, Touch screen, Touch Pad, Joy sticks, Tracking balls
etc.
KEYBOARD: -Keyboard is an important input device
any thing, which we input in the computer, is input by keyboard.
MOUSE: -A device worked by fingers to move the
curser in any desired direction. Mouse is a computer-input device, usually
connected to the computer by a thin cable. Using a hand to remove the mouse in
contact with a flat surface causes a cursor (pointer), on the display screen to
move. A mouse button is pressed it causes a ‘Click’ sound and your massage go
to the computer.
SCANNER: -Many graphic begin left as drawings on
paper and must be convert into a form that a computer package can use this
device is called scanner.
TOUCH SCREEN: -A touch screen is an input device
that allows the user to interact with the computer by touching the display
screen. Early screens used beams of infrared light projected across the screen
surface. Interrupting the beams generated an electronic signal identifying the
location of the screen, which was relayed to software. Modern touch screens use
a thin, durable, transparent plastic sheet overplayed onto the glass screen.
The location of a touch is calculated from the capacitance for the X and Y
axes, which varies based upon where the sheet is touched.
JOYSTICK: -A joystick is a computer peripheral or
general control device consisting of a handheld stick that pivots about one end
and transmits its angle in two or three dimensions to a computer. Most
joysticks are two-dimensional, having two axes of movement, just like a mouse,
but three-dimensional joysticks do exist.
OUTPUT
Output is through which computer give the result
after processing the data. Output used by computer. Computer gives the result
by some devices i.e. Monitor, Printer, Speaker, Plotter, Scanner, Punch card,
Magnetic taps etc. The output as the name implies, provides the results of a
computer operation to the user. This may be a printer, in which case the
information automatically converted to a printed form called Hard copy, or
alternatively data may be displaced on a monitor screen called the Soft copy.
MONITOR: -Monitor is generally used for show output
of any program, any thing, which can process in computer and opening memory are
shown on monitor. The result of monitor is called “Soft Copy”.
PRINTER
Printer is an output device producing data or
information on paper of transferring the information from the computer to
paper. The result of printer is called “Hard Copy”. There are two types of
Printers
1) Impact Printers 2)
Non-Impact Printers
Impact Printers: -Impact printers hit inked ribbons
against papers. Most impact printers are noisy. Impact printer’s work by having
wires or embossed characters strikes a piece of paper on ribbon so that a
character is formed on a paper. This is the principle that operators
conventional typewriters keys. Further classification of impact printer is as
follows:
Dot Matrix Printers: In this type of printer an
inked ribbon runs between the paper and the print-head. The print-head moves
across the paper and goes on printing information. When it has printed a line
completely the paper-feed motor turns the plate. As a result, the paper turns
one line up. The print-head has seven pins in one vertical now. They strike the
ribbon hundred times per second and print dots on the paper. The quality of
print-out is not of a high resolution.
Line Printers: Line printer is one that prints a
complete line of characters at one time, and hence is generally faster than a
character printer.
Impact Printers: -It operates by an electronic beam
passing through a mask containing the various characters and then impinging
upon an electron-sensitive film. The film is later developed and used to
transfer the output data onto hard copy. This type of printer can print as may
as 64000 lines per minute. The printers of this types use other methods of
printer e.g. thermal or electrostatic.
Ink Jet: sprays tiny droplets of ink particles onto
paper. An ink-jet prepares the printout by sharing sheans on ink through tiny
holes in the print head. The resolution (the degree of detail in the print-out)
of an inkjet is almost similar to that of a laser printer.
Laser: uses a beam of light to reproduce the image
of each page using a magnetic charge that attracts dry toner that is
transferred to paper and sealed with heat. A laser printer gives best quality
printouts at a speed. It resembles a photo-copier in its working. A laser
printer can print at a resolution of 300 to 600 DPI (dots per sq. inch). It is
very commonly used for DTP (Desk Top Publishing) jobs. The print-out given by a
laser printer is called the hard copy of the processed information.
SPEAKER: -A speaker is essentially the final
translation machine -- the reverse of the microphone. It takes the electrical
signal and translates it back into physical vibrations to create sound waves.
When everything is working, as it should, the speaker produces nearly the same
vibrations that the microphone originally recorded and encoded on a tape, CD,
LP, etc. Traditional speakers do this with one or more drivers. A driver
produces sound waves by rapidly vibrating a flexible cone, or diaphragm.
C P U
Stand for Central Processing Unit; CPU is the main
part of the computer. It is often called System Box. The CPU is the brain of
the computer. The input and out put devices may vary for different
applications, but there is only CPU for a particular computer.
It is Central : because it is the Center of PC.
It is Processor : because it Process on data and
instructions.
It is Unit : because it is a
Chip (which consist millions of
transistors & consist of ALU, CU and
Memory)
The CPU has three (3) parts ALU, CU and Memory.
ALU
Stands for Arithmetical Logical Unit, ALU are the
section of CPU. Where actual data processing is take place. ALU uses registers
for storage. ALU has two Sections
(i) That
performs all arithmetical and logical operation such as addition, subtraction,
multiplication and division.
(ii) It’s
perform certain logical operations such as equal to, greater than or smaller
than e.g. A<B, A>B, A=B etc and it also perform certain logical
operations of Selecting, Sorting and Comparing.
Registers: -Registers are high-speed storage areas
that temporary store data during processing.
CU
Stand for Control Unit. The CU factions more like a
housemaster. The CU acts as a central nervous system for the other component of
the computer. Means this unit is control all the parts of the computer. It
deals with input as per the instructions using the memory and the ALU. After
processing it send result back to the memory from where they reach the output
device. This is a vital component of CPU that controls all the activities of
the computer system. Its actual task is to fetch, decode and execute an instruction
one at a time.
MEMORY SYSTEM
Memory: -The area inside the computer where
information is stored. Memory is the main part and important part of the CPU,
when any information is feed into the computer, the CPU first send it to the
memory and it is stored there. This memory is called main memory. There are two
types of Memory.
Primary Memory (Internal Memory)
It
is computer memory, which stores data temporary all the program call from
secondary memory these are store in primary memory. It is also called internal
memory of computer. There are two parts of primary memory or main memory.
(1) RAM (2) ROM
RAM: -Stand for Random Access Memory, This memory
is used for temporary storage. This is volatile memory, all the data vanishes
from the RAM as the computer off.
ROM: -Stand for Read Only Memory. This is used for
permanent storage. This is non-volatile memory. ROM is the type of memory that
stores its contents permanently.
Cache Memory: -Cache memory is a special high-speed
memory area that the CPU can access quickly. That works in between RAM and
Processor. Cache memory can be located on the microprocessor or elsewhere on
the motherboard.
Secondary Memory (External Memory)
Secondary storage memory is external memory of computer.
It is permanent memory where data item store permanently. There are many
secondary memory devices such as Hard Disk, Floppy Disk, CD-ROM, CD-R, CD-RW,
DVD and USB Flash Device.
UNIT OF MEMORY
Bit is the unit of memory and Bit is the unit of
measure the data. Computer is consisting of only 0 or 1. That 0 or 1
constitution is one bit. Another large unit of memory is byte. Byte is a single
character like a or b. and two bytes make one computer world, 1 byte consist of
8 bits.
A brief summary
8 Bits = 1 Byte
1024 Bytes = 1 KB
1024 Kilo Bytes = 1 MB
1024 Mega Byte = 1 GB
1024 Gaga Bytes = 1 TB
1024 Tara Bytes = 1 HB (Hex Byte)
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