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CONTENTS
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Input Unit
Output Unit
Memory Unit
Control Unit
Arithmetical Unit
Logical Unit
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Components of Computer:
There are 5 components of computer. It includes Input Unit,
Output Unit, Memory Unit, Control Unit, Arithmetical Unit and
Logical Unit.
MEMORY
UNIT
INPUT
CONTROL
UNIT
ARITHMETIC
UNIT
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OUTPUT
❖ INPUT UNIT:
A computer will only respond when a command is given to the
device. These commands can be given using the input unit or the
input devices.
FOR EXAMPLE: Using a keyboard we can type things on a
Notepad and the computer processes the entered data and then
displays the output of the same of the screen.
The data entered can be in the form of numbers, alphabet, images,
etc. We enter the information using an input device, the processing
units convert it into computer understandable languages and then
the final output is received by a human-understandable language.
Computer Input unit means the device of the input and a part of the
computer hardware which is used for the transport of the data
processing system involves the information devices of the
computer with the control and data signals of the computer.
Input Devices:
In computing, an input device is a piece of equipment used to
provide data and control signals to an information processing
system, such as a computer or information appliance.
The most common input devices are the keyboard, mouse, and
touch screen. Portable keyboard, wireless mouse, and iPhone.
There are hundreds of other input devices, like microphones to
capture sound waves, scanners to capture image data, and virtual
reality devices to capture our body movements.
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TYPES OF INPUT DEVICES:
Keyboard
Mouse
Joystick
Light Pen
Microphone
Monitor
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❖ OUTPUT UNIT:
Computer Output is the device which deals with transmitting the
data of the computer among the device and the clients. The
computer is designed for humans in the form of audio and video
format.
When we command a computer to perform a task, it reverts for the
action performed and gives us a result. This result is called output
there are various output devices connected to the computer. The
most basic of which is monitor. Whatever we write using a
keyboard or click using a mouse, is all displayed on the monitor.
Thus, the output unit gives us the final result once the entire
processing is done within the mechanism of a device.
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❖ MEMORY UNIT:
A memory unit is a small storage device that holds a memory for a
computer and can be accessed through the software.
Memory units are typically used to store the information of the
programs. The computer has two types of storage : volatile and
non-volatile. Volatile storage systems lose data when powered off,
and non-volatile systems do not lose data when turned off.
Memory units store non-volatile data, and they are used to store
your preferences, internet bookmarks and many other items. When
you turn on the computer, you can access the data stored in this
memory device.
The storage capacity of the memory unit differs depending upon
the manufacturer and design. You can find a USB stick with
almost 64 GB storage capacity in the market. However, the
memory stick can be transferred to different devices with flash
drive capability. Using a memory device, you can transfer the hard
drive data from one computer to another. You can also transfer the
data from one device to another over the local network and
internet.
The memory unit is more easily accessible when connected to the
PC’s USB interface slot. You can also access the data stored in the
memory unit through the printer or an external hard drive.
The memory units are used in computers because they frequently
store the data accessed. When you use a web browser, you need to
save the website’s address you are visiting to access that site later
again. This information is usually stored in a computer’s memory
unit, and the data is not lost when you turn off your computer or
remove this storage device from the system.
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BITS AND BYTES
Bits and bytes are the basic building blocks of memory. "Bit"
stands for binary digit. A bit is a one or a zero, on or off, which is
how all computer information is stored. A byte is made up of eight
bits. Eight bits, or a byte, was the original amount of information
needed to encode a character of text. The number was later
standardized as computer hardware changed.
For technical reasons, computer memory capacity is expressed in
multiples of a power of two. The metric prefixes were then applied
to those multiples to provide an easy way to express the very large
numbers of bits and bytes.
Kilo ( Kilobyte or KB )
1024 Bytes
Mega ( Megabyte or MB )
1024 Kilobytes
Giga ( Gigabyte or GB )
1024 Megabytes
Tera ( Terabyte or TB )
1024 Gigabytes
Peta ( Petabyte or PB )
1024 Petabytes
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❖ ARITHMETICAL & LOGICAL UNIT:
An arithmetic-logic unit is the part of a Central Processing Unit
that carries out arithmetic and logic operations on the operands in
computer instruction words.
In some processors, the ALU is divided into two units: an
arithmetic unit (AU) and a logic unit (LU). Some processors
contain more than one AU -- for example, one for fixed-point
operations and another for floating-point operations.
In computer systems, floating-point computations are sometimes
done by a floating point unit (FPU) on a separate chip called a
numeric coprocessor.
How does an arithmetic-logic unit work?
Typically, the ALU has direct input and output access to the
processor controller, main memory (random access memory or
RAM in a personal computer) and input\output devices Inputs and
outputs flow along an electronic path that is called a Bus.
The input consists of an instruction word, sometimes called a
machine instruction word, that contains an operation code or
"opcode," one or more operands and sometimes a format code. The
operation code tells the ALU what operation to perform and the
operands are used in the operation.
For example, two operands might be added together or compared
logically. The format may be combined with the opcode and tells,
for example, whether this is a fixed-point or a floating-point
instruction.
The output consists of a result that is placed in a storage register
and settings that indicate whether the operation was performed
successfully. If it isn't, some sort of status will be stored in a
permanent place that is sometimes called the machine status word.
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In general, the ALU includes storage places for input operands,
operands that are being added, the accumulated result (stored in an
accumulator ) and shifted results. The flow of bits and the
operations performed on them in the subunits of the ALU are
controlled by gated circuits.
The gates in these circuits are controlled by a sequence logic unit
that uses a particular algorithm or sequence for each operation
code. In the arithmetic unit, multiplication and division are done by
a series of adding or subtracting and shifting operations.
There are several ways to represent negative numbers. In the logic
unit, one of 16 possible logic operations can be performed -- such
as comparing two operands and identifying where bits don't match.
The design of the ALU is a critical part of the processor and new
approaches to speeding up instruction handling are continually
being developed.
What type of functions do ALUs support?
The following are a few examples of bitwise logical operations and
basic arithmetic operations supported by ALUs:
Addition. Adds A and B with carry-in or carry-out sum at Y.
Subtraction. Subtracts B from A or vice versa with the difference
at Y and carry-in or carry-out.
Increment. Where A or B is increased by one and Y represents the
new value.
Decrement. Where A or B is decreased by one and Y represents
the new value.
AND. The bitwise logic AND of A and B is represented by Y.
OR. The bitwise logic OR of A and B is represented by Y.
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COMPUTER MS WORD ASSIGNMENT
SUBMITTED BY: SANIA MUJAHID
ROLL NO: 11
SUBMITTED TO: DR.MUFASSRA NAZ
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