Session - 1
Basics Of Computers
VIVEK KUMAR SINGH
vivek@bhu.ac.in
A Desktop Machine
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Introduction to Computers
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A Computer System
• Hardware
• Software
• User
User
Software
Hardware
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A Computer System (Contd.)
• In general, a computer is a machine which
accepts data, processes it and returns new
information as output.
Processing
Data
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Information
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Software
• Software is set of programs (which are step by
step instructions) telling the computer how to
process data.
• Software needs to be installed on a computer,
usually from a CD.
• Softwares can be divided into two groups:
- System SW
- Application SW
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Software (Contd.)
System Software
• It controls the overall operation of the system.
• It is stored in the computer's memory and
instructs the computer to load, store, and
execute an application.
• Examples: Operating System (OS), Translators
DOS, Windows, Unix etc.
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Software (Contd..)
Application Software
• They are Softwares written to perform specific
tasks.
• The basic types of application software are:
word processing, database, spreadsheet,
desktop publishing, and communication.
Examples: MSOffice, Tally, MSOutlook,
ISBS, MODBANKER BANKSOFT
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Advantages of Using Computers
• Speed: Computers can carry out instructions in less
than a millionth of a second.
• Accuracy : Computers can do the calculations without
errors and very accurately.
• Diligence : Computers are capable of performing any
task given to them repetitively.
• Storage Capacity : Computers can store large
volume of data and information on magnetic media.
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History of Evolution Of Computers
Two Eras:
• Mechanical Era (Before 1945)
• Electronic Era (1945 - )
Can be divided into generations.
•
•
•
•
First Generation (1945 – 1954)
Second Generation (1955 – 1964)
Third Generation (1965 – 1974)
Fourth Generation (1975 - )
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Types of Computers
On the basis of Computing Power & Size:
•
•
•
•
Laptop / Palmtop
Micro Computer / Desktop
Mini Computer / Mainframe
Super Computer
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Language of Computers
• Computers only understand the electronic
signals.
Either Current is flowing or not.
• Current Flowing
: ON
• Current Not Flowing : OFF
• Binary Language
• ON : 1
• OFF : 0
• Bit, Byte, KB, MB, GB
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Computer Network
• A Computer Network is interconnection of
Computers to share resources.
• Resources can be : Information, Load,
Devices etc.
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Types Of Computer Networks
On the basis of Size:
• Local Area Network (LAN)
Its a network of the computers locally i.e. in
one room, one building.
• Wide Area Network (WAN)
Its a network of the computers spread widely
geographically.
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Benefits of Computer Networks
•
•
•
•
•
•
Information Sharing
Device Sharing
Load Sharing
Mobility
Fast Communication
Anywhere Anytime Banking
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Internet
• Internet is a huge network of computer networks.
• Internet provides many services:
– Email
– World Wide Web (www)
– Remote Login (Telnet)
– File Transfer (FTP)
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End Of Session #1
ANY Queries ??????
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CPU ( Central Processing Unit)
• The central processing unit (CPU), also
known as just a "processor”, is the "brain"
of your computer.
• It contains various electronic circuits.
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VDU (Monitor)
• This is the television-like screen where the results
of a computer's tasks are displayed.
• Monitors come in all sizes, but most commonly
they are either 15 or 17 inches
(measured diagonally from one corner of the
screen to the opposite corner).
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Keyboard
• The keyboard looks like a typewriter.
• It contains all the letters of the alphabet,
numbers and some special symbols.
• It operates like a typewriter keypad, but
instead of moving an arm, which strikes the
paper, it sends an electronic impulse to the
computer, which displays a character on the
monitor.
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Mouse
• Its
a device that is used to control the computer.
A cable connects the mouse to the computer.
• When the mouse is moved on a pad, called a
mouse pad, the cursor on the screen moves.
• A cursor is a small symbol displayed on the
computer screen (normally a diagonal arrow that
is used as a pointer) that shows you what the
mouse is referencing on the screen.
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Printer
• A printer is designed to output information
from a computer onto a piece of paper.
• There are three kinds of printers:
dot matrix, laser,
and inkjet.
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Scanner
• A scanner is a device used to copy an image off
paper and convert it into a digital image, which
can be saved as a computer file and stored on a
hard drive.
• Scanners can also use a special kind of
technology called Optical Character Recognition
(OCR) to read text from paper and save it as an
editable document file
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Session # 2
Inside The CPU Cabinet
A Look Inside.
Floppy
CD
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A Look Inside ..
power
supply
CD-ROM
drive
floppy
drive
cards
hard
drive
motherboard
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A Look Inside…
• Identify all the major components:
– Power Supply
– Motherboard
– Memory
– Card Slots
– Cards (sound, video, network)
– CPU, heatsink and fan
– Drives (floppy, hard and CD-ROM)
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What these components do.
• Power Supply – (heart) supplies power to all the circuitry
and devices.
• Motherboard – (body) acts as a manager for everything
on the computer – connects all the other components
together.
• CPU – Central Processing Unit – (brain) this does all the
work of computing.
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What these components do..
• RAM – Random Access Memory – (short-term
memory) holds data and program instructions
that the computer is currently using.
• Hard Drive – (long-term memory) holds all of the
information that needs to be stored between
uses of the computer.
• Floppy and CD-ROM drives – (mouth/ears) allow
you to give data to the computer and take data
away from the computer.
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What these components do…
• Card Slots – (fingers) Allows other components to
be added to the computer.
• Video card – (face) Does all of the processing
necessary to get stuff looking nice on screen,
quickly.
• Sound card – (vocal cords) Allows sounds from
HD or CD-ROM to be played.
• Network Card – (telephone) allows computer to
talk to other computers over a wire.
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Power Supply
SMPS – Switch Mode Power Supply
Switching Transistors
Outputs + 5V, -5V, +12 V, -12 V
Typical Costs are:
• ATX
– Rs.700
• Non ATX – Rs.300
Usually, SMPS comes with the CPU Cabinet.
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Motherbo
ard
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CPU
CU
• A Single Chip
ALU
Memory
Registers
Examples: Intel Family – Pentium 4, 3, 2, Pentium,
XEON, Itanium
AMD
-- Athlon, K62
IBM
-- Cyrix
Motorola -- 68000 Series
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RAM
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Hard Drive
We won’t remove this.
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Floppy Drive
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CD-ROM Drive
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Ribbon Cables
polarized
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Video Card
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Sound Card
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Back of
Computer
Remove these screws
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End of Session # 2
Queries???
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CPU
• The central processing unit or (CPU) is the "brain"
of your computer. It contains the electronic circuits
that cause the computer to follow instructions
from memory.
• The CPU contains three main parts, all housed
in a single package (Chip):
– Control Unit (CU)
– Arithmetic Logic Unit (ALU)
– Memory
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BACK
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Session # 3
Computer Peripherals
Major Peripherals
•
•
•
•
•
•
•
•
Keyboard
Mouse
Hard Disk
Floppy Disk
CD ROM
Printer
Scanner
Joystick
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Keyboard
• Keypad contains:
– Alphabets
– Numbers
– Special Symbols
– Function Keys
•
•
•
•
qwert Keyboard (Typewriter Keyboard).
On key press it sends a code (ASCII Code) to the CPU.
Plug N Play device.
Typical Cost is Rs.300 – Rs.1200
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Mouse
• Pointing & Click Device.
• Two / Three Buttons
• Wheel / Optical Mouse
• Normally Left Click – Select/ Run
Right Click – Popup Menu
• Typical Cost is Rs.100 – Rs1000
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Hard Disk
• Magnetic Memory Device.
• Non-removable storage device.
• Several Circular Magnetic Disks are housed in a
single case.
• Data is stored as 1s & 0s.
• Typical Capacity is 20 GB -80 GB
• Typical Cost is Rs.2200 – Rs6000
• Cost/Bit is Low.
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Floppy Disk
• Magnetic Memory Device.
• Removable storage.
• A single circular mylar plastic disk, coated with magnetic
material is packed in a protective plastic casing.
• Typical size is 3.5” & Capacity is 1.44MB
• Typical Costs are:
• Floppy Drive -- Rs.300
• Floppy Disk -- Rs.10
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CD ROM
• Optical Device.
• Removable Storage.
• Read Only Memory.
• Typical Capacity is 550 Mb – 800MB
• Typical Costs are:
• Drive
-- Rs.1000
• Disk Rs10 – Rs.35
• Related Terms:
• CD Writer
• WORM
• CD RW
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Printer
• Output Device, Produces Hard Copy
• Types:
– Dot Matrix
– Inkjet
– Laser
• Typical Cost Ranges from Rs.3500 – Rs.2 lacs
• Related Terms:
– Impact – Non Impact
– Ribbon, Cartridge, Toner, Duty Cycle
• Major Vendors in India:
– HP, Cannon, Samsung, TVS, Epson etc.
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Scanner
• Input Device, Converts a hard copy into a
computer file.
• Used to Scan Signatures, Photographs etc.
• Optical Device.
• Typical Cost Rs.4000 – Rs.75000
• Major Vendors in India:
– HP, Umax, Cannon
• Nowadays Scanners with OCR produces
editable documents.
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End of Session #3
Queries???
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Session - 4
Overview of Operating System
What is Operating System
 OS is system software, which may be viewed as
collection of software consisting of procedures for
operating the computer.
 It provides an environment for execution of programs
(application software).
 It’s an interface between user & computer.
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Computer Machine
(Hardware)
Machine Language
(Low Level Language)
Operating System
Human Understandable Language
(High Level Language)
User / Programmer
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Types of OS
Multiprogramming OS
Multitasking/Multiprocessing
Multiuser OS
Time Sharing OS
Real Time OS
Distributed OS
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A Second Classification
This Classification is based on the type of interface
Operating System provides for the user to work in.
Character User Interface (CUI)
The User has to type the commands on the
command prompt to get the work completed.
Ex. DOS, UNIX.
Graphical User Interface (GUI)
The User need not type any commands. He/She
just point and clicks on the desired Icon to get the
work done.
Ex. Windows (9X, XP, NT, 2000), Linux.
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Functions of OS
File Management
Memory Management
Process Management
Device Management
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Types of Processing
Serial Processing
The job is processed at the time when
it is submitted.
Batch Processing
The similar jobs are bunched together and
are kept for processing at an later time.
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MS-DOS Overview
 MS-DOS is an acronym for MicroSoft Disk Operating System
 It is a CUI based operating system.
 It provides user with a command prompt (generally called as C:\) where
various command could be typed.
 When one operates in the DOS environment, one interacts with the
command interpreter, which interprets the commands given by user.
 It provides an environment for execution of various application programs
like MS-Word, MODBANKER, ISBS etc.
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What is Command
 It is a string of characters which tells the computer what to do.
 When one types commands to a computer, one is conversing
with the operating system's command interpreter.
 For example, to copy a file called file.txt from the 3-1/2"
floppy drive to the hard drive, one could type
C:\> copy a:\file.txt c:\
The word "copy" is a DOS command which causes files to be
copied from one location to another
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Entering the DOS Environment
 If the OS is DOS then the system will directly show prompt (C:\>)
 If the OS is windows one must either terminate the Windows environment, or
open a DOS shell within the Windows environment.
Ist Method: Terminating Windows Environment
Select “Restart in MS-DOS Mode” from Shut Down in
Menu.
Start
IInd Method: Opening DOS Shell in Windows
Select Start>Programs>Accessories>Command Prompt (XP)
Start>Programs>Accessories>MS-DOS Prompt (98)
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Files and Directory
Files
 A file is a collection of Records.
 It is the smallest unit of File System (Storage) in a computer.
 Any document created using computer is a file. This document could either be a
letter, any excel sheet, any image or even a database.
Directory
 A collection of files is directory (in DOS) or folder (in Windows)
 It is analogous to the Office Folder which contains various documents.
 A directory/folder eases the management of related files/ documents, like the
various circulars related to personnel could be placed in a directory called
“personnel” and all the circulars related to loans could be placed in a directory
called “loans”.
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Filenames in DOS?
 The filename in DOS have the following format.
<name>.<ext>
 It has two parts the name and the extension.
 The name could be of 8 characters and the extension of 3
characters.
 The filename can contain alphabets and numbers. It cannot
contain any special character other than underscore (_) and
also no spaces.
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Organization of files in DOS
The DOS file system is a hierarchical file system.
Files are collected into directories, and directories may contain
both files and other directories.
There is always a directory which is not contained by any other,
called the root which is represented by the backslash '\'
character.
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Organization of files in DOS (Contd.)
Concept of Path: Every file can be specified by enumerating
all of the directories between the root and it, separated by the
backslash '\' character, and appending the file name to the end.
The drive which contains the root is specified at the head of the
path, separated from the root by a colon (':')
The hard drive is most commonly known as the C: drive, and
the floppy drives are usually called A:(3-1/2 inch) and B: (51/4 inch).
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Organization of files in DOS (Contd.)
/
circulars
officer.txt
loans
personnel
new.dat
january
february
retire.txt
Fig. Hierarchical Structure of Files
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rest.txt
abc.txt
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Some DOS Commands
dir: Listing of all the directories.
C:\> dir
cls: Clears the screen.
C:\> cls
copy con: Creates a file.
C:\> copy con <filename>
< Write your Contents Here>
Press Ctrl-Z (^Z) to finish writing.
Ex:
C:\> copy con test.dat
Lets Make UCO a top class Bank.
Ctrl-Z (^Z)
1 file(s) copied. (A Message will be shown on the system)
This will create a file named test.dat having some data.
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Some DOS Commands (Contd.)
edit: Edits a file.
C:\> edit <filename>
This will open a editor window where the contents of file can be seen. These
contents could also be edited here and on saving, the contents of file will
change.
type: Displays the content of a file.
C:\> type <filename>
This will display the contents of file on the computer. The contents of file could
only be viewed but could not be changed, as in the case of edit.
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Some DOS Commands (Contd.)
md: Make Directory.
C:\> md (directory name>
This will create a directory with the specified name.
cd: Change Directory.
C:\> cd (directory name>
This will change the directory from current directory to the specified directory.
rd: Remove Directory.
C:\> rd (directory name>
If the directory is needed to be removed permanently from the computer, use
this command. For this command to be executed it is necessary that the
directory should be empty andIntroduction
user should
be on a directory above it.
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Some DOS Commands (Contd.)
copy: Copies a file.
C:\> copy <source> <destination>
This will copy the file from the source location to the specified destination. The
command creates a copy of the file on the destination i.e. the file would be
found on both the location.
move: Moves a file.
C:\> move <source> <destination>
This will move the file from the source location to the specified destination. The
file from the source location would be removed and would be moved to the
destination.
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Some DOS Commands (Contd.)
ren: Renames a file.
C:\> ren <old filename> <new filename>
This will change the name (rename) of the file to a new name as
specified.
del: Deletes a file.
C:\> del <filename>
This will delete the file permanently from the system.
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Overview of Windows
 Windows is an GUI based operating system.
 It is also developed by Microsoft Corporation, which is headed by
Mr. Bill Gates.
 Over the years the Microsoft have evolved various versions of
Windows. Win95, Win98, Win2000, Win ME, Win NT, Win XP.
 It gives user a handy environment where he doesn’t have to
remember and learn the syntaxes of various commands as is the case
in DOS.
 The user can just point and click on the Icons provided to him on the
screen.
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Folders and Documents
 Folders are a way to organize your documents within drives in Windows as
are the directories in DOS.
 A document is each thing that you create on a computer. A document can
be made using any type of software.
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End of Session #4
Queries???
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QUIZ
1. Name any four devices of a Computer.
Keyboard, Mouse, Scanner, Light Pen.
2. What is the job of CPU?
Central Processing Unit controls and coordinates
all the activities of the computer.
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QUIZ
3. What is the unit of measuring the speed of the
processor?
Mega Hertz or Kilo Hertz ( No. of CPU
Cycles/second)
4. What is a computer network?
It is interconnection of computers to make a
LAN,MAN or WAN.
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QUIZ
5. Name any three storage devices.
Hard Disk, Magnetic Tape, Compact Disk.
6. What is command to create directory?
C:\>MD <<dir-name>>
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QUIZ
7. What is Internet?
It is the network of networks.
8. What are different types of printers?
Dot Matrix Printer, Inkjet
Laser
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QUIZ
9.What is the use of Scanner?
It is used to copy the real
paper to
be stored as
the computer.
image
on
digital image in
10. Why Operating system is required?
It is required to provide the interface
between the user and the
computer.
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QUIZ
11.
What is the difference between
Primary
Storage and Secondary
Storage?
Primary Storage is temporary
storage,
fast and costly.
Secondary storage is permanent, slow and
cheap.
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QUIZ
12. What is MODEM. Why it is required?
It is Modulator Demodulator. It is used to
connect the PC to the Internet using Analog
Telephone Lines.
13.
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What is the maximum length
name in DOS?
First Name- 8 characters, Last
characters.
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file
Name- 3
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QUIZ
14. What is the command in DOS to
contents of the file?
C:\> Type<<File Name>>
see the
15. What are the two types of Software?
Systems Software
Application Software
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