Transcript information technology

information technology
Computer Users
• Use computers for work and personal tasks.
• Do not necessarily have much technical
knowledge.
• When they need technical help, they usually
obtain it from the computer professionals.
• To use computers efficiently, however, you
must become computer literate and computer
efficient.
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Computer Literacy & Competency
• understanding what a computer is and what it can do
• using skills to meet information needs and improve
productivity
• Be able to transfer basic skills to new systems and new
software.
• master the computer terminology
• Learn the functions of the parts of a computer system
• Produce the information needed and perform the required
tasks
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Understanding computers
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How does a computer work?
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Idiot servant
Very good with a small number of tasks
Can perform excellent for a good master
what can computers do well?
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Store and retrieve numbers
Add, subtract, multiply, and divide
Fast and accurate
Follow a list of instructions
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Computer
• Computer is an electromechanical (it has
electronic as well as
mechanical
components),
programmable (use as
per one’s need) device
that accepts data and
processes it to
meaningful information
with a very high speed
and accuracy.
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Advantages & Limitations
EVERY INVENTION SHOWS A NUMBER OF
ADVANTAGES, WHICH POPULARIZES ITS USE AND ON
THE OTHER HAND IT LEAD TO CERTAIN LIMITATIONS
ALSO, THAT PROVIDE MOTIVE FOR INVENTORS/
SCIENTISTS FOR FURTHER DEVELOPMENT
Characteristics
• Speed
– It works with a very high speed.
• Accuracy
– results calculated by computer are always accurate.
• Reliability
– The computer is very reliable as it is always available at your
service. Whenever you need it will perform its duty.
• Storage
– It has a capability of storing permanently. Any data stored in
computer can be retrieved any time.
Characteristics
• Automation
– Once initiated, it will start working and work till the job finishes.
• Versatility
– The same computer can serve for different purposes. It means
that same machine can be used for educational purpose or
entertainment or diagnostics or publication, prediction etc.
• Communication
– With the invention of Internet technology now the computers
are capable of exchanging messages, data, voice, audio, video
etc.
• Diligence
– With the time, it never get tired. It can work for hours, days,
month or years without any break.
Characteristics
• No Feelings
– It is emotionless. Effect of environment, users feelings
or biasness do not divert or hamper its functioning.
• Consistency
– It is a very consistent machine. It will provide same
results for same set of data whenever you instruct him
for same job.
• Precision
– results given by computers are exact and accurate.
Limitations
• Programmed by human
– Being an idiot servant it is the duty of machine that it performs
as per the instructions given by its master/user.
• No Intelligence/No decision making power
– has no intelligence, that is why it cannot take any decision unless
defined by its user.
• Emotionless
– Computer is purely mechanical as far as its working is concerned.
It is not concerned with users’ physical or mental condition.
• Curtail human capabilities
– It is biggest limitation of computer. People are so dependent on
computer that now they need it even for small problems.
Elements of computing process
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Hardware
Software
Data
People
Procedure
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Plastic, metal and glass components,
things you can trip over!
Hardware
• Processing
– Components responsible for processing/calculation fall
under processing hardware category. E.g. Central
Processing Unit (CPU).
• Memory
– Storage area which is reserved for data and
communicated with processing hardware comes under
memory hardware category. E.g. Random Access Memory
(RAM), Read Only Memory (ROM).
• Input
– The devices through which we can give instructions to the
computer fall under this category. E.g. Keyboard, mouse.
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Plastic, metal and glass components,
things you can trip over!
Hardware
• Output
– The devices through which computer provide us
results after processing are known as output
hardware devices. E.g. Monitor, Printer.
• Storage
– The devices which have the capability of storing data
permanently lie on this category. E.g. Floppy, Hard
Disk, CD.
• Communication
– The devices which enable our computer for sending
or receiving messages fall under this category. E.g.
Modem.
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Physical Structure
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Components of a computer system
Software
• Computer software or software is a collection of computer programs
(set of instructions is known as computer program) and related data
that provide instruction to the computer what to do and how to do.
More technically, software is a set of programs, procedures,
algorithms and its documentation designed/developed for a specific
purpose.
• Software may divide into three broad categories:
– System Software
– General Software
– Application Software
System Software
• System software is computer software designed to operate
the computer hardware to provide basic functionality and to
provide a platform for running application software.
• It includes programming languages, program translators,
operating systems, device drivers and utilities programs.
System software is also responsible for managing hardware
components, so that they can work together harmoniously.
Language
• A language is a media to communicate with
others.
• A source and object is necessary for
communication.
• Object must understand the content
communicated by the source.
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Types of Languages
Language
Low Level Language
Machine Language
High level Language
Procedural Languages
Object-oriented languages
Assembly Language
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Low Level Languages
• Machine language
– It uses only two digits 0s and 1s to write an instruction
– It is machine dependent, which means – programs written on one computer
cannot be used on other computer unless hardware architecture is exactly
same.
– It is near to computer rather the user.
• Assembly language
– It uses mnemonics i.e. small codes which comprises of ADD, SUB, MPY, DIV,
LOAD etc. for writing instructions.
– It is also machine dependent
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High Level Languages
• High-level programming languages - uses
math-like and English-like expressions to
represent user ideas.
– less machine-dependent
– simplify programming for user (focus on user’s task
not computer)
– programs are portable between machines.
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High Level Languages
• Procedural Language (e.g. BASIC, FORTRAN, COBOL, PASCAL, C, etc.)
– In procedural language, programmer specifies an explicit sequences of steps to
follow to produce a result.
• Object Oriented Language (Small Talk, Visual Basic, C++, JAVA etc.)
– Object-oriented programming language model organized around "objects" rather
than "actions" and data rather than logic. Historically, a program has been viewed
as a logical procedure that takes input data, processes it, and produces output data
– Object-oriented programming takes the view that what we really care about are
the objects we want to manipulate rather than the logic required to manipulate
them. Examples of objects range from human beings (described by name, address,
and so forth) to buildings and floors (whose properties can be described and
managed) down to the little widgets on your computer desktop (such as buttons
and scroll bars).
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Translation
• Computer does not recognize high level language. To recognize it, it must
be translated into machine language.
• Translation changes the source code into object code in machine
language.
• Object code must be linked with other required codes (e.g. operating
system routines, library routines) to form an executable program.
• The executable program is then loaded into the computer memory to be
run.
Translation leads to the compilation of an executable program file (*.exe)
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Translators
• Assembler
– Translates Assembly language program to machine language.
– Translating mnemonic operation codes to their machine
language equivalents
– Assigning machine addresses to symbolic labels
Source Code
Mnemonic Opcode
Symbol
Assembler
Object Code
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Translators
• Compiler
– A compiler is defined as a computer program that is used to
convert high level instructions or language into a form that
can be understood by the computer. Since computer can
understand only in binary numbers so a compiler is used to
fill the gap otherwise it would have been difficult for a
human to find info in the 0 and 1 form.
– There are specific compliers for certain specific languages or
tasks. Compliers can be multiple or multistage pass. The first
pass can convert the high level language into a language that
is closer to computer language. Then the further passes can
convert it into final stage for the purpose of execution.
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Source
Object
File
File
Linker
Runtime
Library
Executable
Program
Translators
• Interpreter
– High level instruction or language is converted
into machine language by an interpreter line-byline.
– An interpreter, the high level program is executed
directly.
– Programmers prefer interpreters while making
small sections as this saves time.
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Compiler vs. Interpreter
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• Compiler
– Converts the high level
instruction into machine
language.
– Before execution, entire
program is executed by the
compiler.
– List of errors is created by the
compiler after the compilation
process.
– An independent executable file
is created by the compiler.
• Interpreter
– Converts the high level
instruction into an
intermediate form
– After translating the first line,
it executes it and so on.
– An interpreter stops
translating after the first error.
– Interpreter is required by an
interpreted program each
time.
Operating System
• An OS manages and coordinates the function performed by the
computer hardware, (including the CPU, input/output devices,
secondary storage devices, and communication) and network
equipment.
• It tracks of each resource and determines that who gets what.
• For large systems, the OS has even greater responsibilities and
powers. It is like a traffic cop -- it makes sure that different
programs and users running at the same time do not interfere
with each other. The operating system is also responsible for
security, ensuring that unauthorized users do not access the
system.
Classification of Operating System
• Multiuser: Allows two or more users to run programs at the same
time. Some operating systems permit hundreds or even thousands
of concurrent users.
• Multiprocessing: Supports running a program on more than one
CPU.
• Multitasking: Allows more than one program to run concurrently.
• Multithreading: Allows different parts of a single program to run
concurrently.
• Real Time: Responds to input instantly. General-purpose operating
systems, such as DOS and UNIX, are not real-time.
Tasks of Operating System
• Processor Management: This involves ensuring that all
the system resources receive sufficient processes time
for expected functioning as well as making sure that
the processer is used to its optimum capacity.
• Memory/Storage Management: Computer systems
have different types of memories such as temporary
(RAM, Cache, etc.) as well as permanent memories
(Hard Drives, USB Drives, etc.). It is the job of an
Operating System to allocate the relevant and
necessary memory space to the applications & devices
for efficient and optimum processing of information.
Tasks of Operating System
• Device Management: Managing the inputs and outputs
of various devices / peripherals is also one of the critical
functions of an Operating Systems. With the help of
device drivers, the OS controls flow of information with
the necessary allocation of system resources to ensure
correct input and output.
• Application Management: As the OS manages the
devices using drivers, it also manages the various
applications running on a computer using different
Application Program Interfaces (APIs). Based on the data
received from the application through the APIs, the OS
performs actions to provide the expected results.
Tasks of Operating System
• User Interface: A user interface provides a
consistent way of interaction between the user
and the computer system. The OS acts as an
engine to provide means of interaction
between user and computer through the user
interfaces.
– GUI (Graphical User Interface)
– CLI (Command Line Interface)
Device Drivers
• A device driver is a component that Windows
uses to provide I/O services for and interact
with an underlying device, such as a modem
or network adapter. Rather than access the
device directly, Windows loads device drivers
and calls functions in the drivers to carry out
actions on the device. Drivers are hardwaredependent and operating-system-specific.
Utility Programs
• Utility programs are designed to help analyze,
configure, optimize or maintain a computer. A
single piece of utility software is usually called
a utility or tool. Utility program usually
focuses on how the computer infrastructure
(including the computer hardware, operating
system, application software and data storage)
operates.
Utility Programs
• Anti-virus utilities scan for computer viruses.
• Backup utilities can make a copy of all
information stored on a disk, and restore either
the entire disk (e.g. in an event of disk failure) or
selected files (e.g. in an event of accidental
deletion).
• Disk checkers can scan operating hard drive.
• Disk cleaners can find files that are unnecessary
to computer operation, or take up considerable
amounts of space. Disk cleaner helps the user to
decide what to delete when their hard disk is full.
Utility Programs
• Disk compression utilities can transparently
compress/uncompress the contents of a disk,
increasing the capacity of the disk.
• Disk defragmenters can detect computer files
whose contents are broken across several
locations on the hard disk, and move the
fragments to one location to increase efficiency.
• Disk partitions can divide an individual drive into
multiple logical drives, each with its own file
system which can be mounted by the operating
system and treated as an individual drive.
Utility Programs
• File managers provide a convenient method of
performing routine data management tasks, such
as deleting, renaming, cataloging, un-cataloging,
moving, copying, merging, generating and
modifying data sets.
• Screensavers were desired to prevent phosphor
burn-in on CRT and plasma computer monitors by
blanking the screen or filling it with moving images
or patterns when the computer is not in use.
Contemporary screensavers are used primarily for
entertainment or security.
• System monitors for monitoring resources and
performance in a computer system.
General Software
• Word processor
– A word processor, or word processing program, does
exactly what the name implies. It processes words. It
also processes paragraphs, pages, and entire document.
– Some examples of word processing programs include
Microsoft Word, WordPerfect (Windows only),
AppleWorks (Mac only), and OpenOffice.org.
• Spreadsheet
– A table of values arranged in rows and columns. Each
value can have a predefined relationship to the other
values.
– Lotus 1-2-3 and Excel are the most popular spreadsheet
programs.
General Software
• Database Management System (DBMS)
– A software package with computer programs that control the
creation, maintenance, and use of a database.
– A database is an integrated collection of data records, files,
and other objects.
• Browser
– A software application for retrieving, presenting, and
traversing information resources on the World Wide Web.
– The major web browsers are Firefox, Google Chrome,
Internet Explorer, Opera, and Safari.
• Email
– A method of exchanging digital messages from an author to
one or more recipients.
Application Software
• Enterprise resource planning (ERP)
– It integrate internal and external management
information across an entire organization,
embracing finance/accounting, manufacturing,
sales and service, customer relationship
management, etc.
– Their purpose is to facilitate the flow of
information between all business functions inside
the boundaries of the organization and manage
the connections to outside stakeholders.
Characteristics
• An integrated system that operates in real time
(or next to real time), without relying on periodic
updates.
• A common database, which supports all
applications.
• A consistent look and feel throughout each
module.
• Installation of the system without elaborate
application/data integration by the Information
Technology (IT) department.
Examples
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Finance/Accounting
Human resources
Manufacturing
Supply chain management
Project management
Customer relationship management
Data services
Access control
CLASSIFICATION ON THE BASIS OF
WORKING PRINCIPALS
Analog Computer
• Uses continuous physical phenomena such as
electrical, mechanical or hydraulic quantities
to model the problem being solved
• For example:
– Thermometer
– Speedometer
– Petrol Pump Meter
– Multimeter
– Slide Rule
Digital Computer
• Performs calculations and logical operations with
quantities represented as digits, usually in binary
system
• Bit – (Two-state: 0,1/Present, Absent etc.
• 8 Bits = 1 Byte
– Can represent 256 different characters
– Called Single-Byte-Character-Set (SBCS)
– Standard for this representation is ASCII (American
Standard Code for Information Interchange)
Hybrid Computers
• A combination of computers those are capable of
inputting and outputting in both digital and
analog signals
• It accepts a continuously varying input, which is
then converted into discrete values in digital
processing
• For example, computers used in hospital for
measuring heart beat of a patient.
• Hybrid machines are generally used in scientific
applications or in controlling industrial processes.
CLASSIFICATION ON THE BASIS OF SIZE
AND DATA PROCESSING POWER
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Personal Computer/Microcomputer
Mini Computers
Mainframe Computers
Super Computers
Workstations
Server
Personal Computer/Microcomputer
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CPU: Microprocessor
Read only Memory (ROM)
Random Access Memory (RAM)
IBM and IBM Compatible
Apple Macintosh: Multimedia application
Multiuser
Notebook, laptop, palmtop, PDAs, Pocket
computer
Mini Computer
• Multiuser Computer with Intelligent and
Dump Terminals
• Own hardware and Operating System
• Data general Nova, DEC, PDP-11 and IBM
Series/1
• Primary memory: 640KB to few MB
• Supports: BASIC, FORTRAN, COBOL, PASCAL, C
Mainframe Computer
• Multiuser, can support 1000s of remote
terminals
• IBM, Honey-well, Burroughs, NCR, CDC,
Sperry
• Application: huge data processing
Super Computer
• Built by interconnecting 100s of
microprocessors
• Mainly used for Defense, whether forecasting,
biomedical research, remote sensing, aircraft
design etc.
• CRAY, YMP, NEC, SX-3 and PARAM
• Speed is measured in FLOPS (Floating point
operations per second), extended to TFLOPS
(1012), PFLOPS (1015)
Workstation
• Based on different architecture of CPU called
RISC (Reduced Instruction Set Computing),
which results faster processing.
• Runs mainly on DOS, Unix, OS/2, NT, UNIX
• 3D mechanical design, engineering
simulation, animation, rendering of images,
mathematical plots
Server
• Provides services to other computing systems
called clients over a network
• Dedicated functionality
– Web servers
– File/Print servers
– Database servers
– Enterprise servers
IN COMPUTER SYSTEM, DIFFERENT PARTS OF A COMPUTER
ARE ORGANIZED IN SUCH A WAY THAT, IT HELPS TO
PERFORM VARIOUS OPERATIONS TO COMPLETE THE GIVEN
SPECIFIC TASK.
TECHNICALLY SPEAKING, COMPUTER IS A HIGH-SPEED
ELECTRONIC DATA PROCESSING MACHINE.
Basic computer operations
Control Unit
Input Devices
Arithmetic/
Logic Unit
Registers
Memory
Secondary Storage
Output
Devices
Function
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Input
Storage
Processing
Output
Control
Central Processing Unit (CPU)
• CPU is the brain of the computer; it reads and
executes program instructions, perform
calculations, and make decisions. The CPU is
responsible for storing and retrieving
information on disks and other media and
also directs the flow of traffic throughout the
computer system.
CPU Generation
i8088
FIRST
i8086
SECOND
i80286
THIRD
i80386DX
i80386SX
i80486SLC
FOURTH
i80486DX
i80386SX
i80486DX4
FIFTH
Pentium
AMD K5
Cyrix 6x86
SIXTH
Pentium Pro
SEVENTH
AMD Athelon
EIGHTH
Intel Itanium
Pentium II
Pentium 4
AMD
Sledgehammer
Celeron
Pentium
MMX
Xeon
Cyrix 6x86MX
AMD K6-2
Pentium III
AMD K6-3
VIA Joshua
Intel Processors
YEAR
PROCESSO SPEED
R
DATA WIDTH
MIPS
1974
8080
2 MHz 8 bits
0.64
1979
8088
5 MHz 16 bits, 8 bit
bus
0.33
1982
80286
6 MHz 16 bits
1
1985
80386
16 MHz 32 bits
5
1989
80486
25 MHz 32 bits
20
1993
PENTIUM
60 MHz 32 bits, 64 bit
bus
100
1997
PENTIUM II
233 32 bits, 64 bit
~300
Features of CPU
• Clock speed
– It is a measure of how quickly a computer completes basic
computation and operations.
– Measured in Hertz (2.4 GHz=2,400,000,000 cycles/sec)
• Cache
– Cache acts as temporary memory and boosts processing power
significantly
– L1 cache is inbuilt with CPU and works at the speed of CPU. It is
divided into two section one for data and other for instruction.
– L2 resides on motherboard and delivers slower performance as
compared to L1
– L3 is also located on motherboard and it works between
microprocessor and main memory. It works with L1 and L2 to
improve computer performance.
Control Unit
• Directs the entire computer
system to carryout stored
program instructions.
• Communicate with ALU and
Main Memory.
• Uses the instruction
contained in the Instruction
register to decide which
circuits need to be activated
• The process of reading an
instruction, is often referred
to as the fetch execute
process.
Instruction Register
Program Counter
+1
Arithmetic Logic Unit
• Executes arithmetic and
logic operations
• Accumulator is used to
accumulate results. It is the
place where the answers
from many operations are
stored temporarily before
being put out to the
computer’s memory
• The general-purpose
registers hold data on
which operations are to be
performed by the ALU
Accumulator
General-Purpose Registers
Memory
• A typical computer has:
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– Level 1 and level 2 caches
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– Normal system RAM
– Virtual memory
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– A hard disk
CPU
Cache
RAM
Part of the computer that holds
data and instructions for
processing
Closely associated with the CPU,
but in actual, it is separate.
Also called Primary Memory,
Main Memory, Volatile memory.
Virtual
Memory
Hard Disk
Virtual memory
• 32 or 64 MB of RAM is available for the CPU
• With virtual memory computer look at RAM for
areas that have not been used recently and copy
them to HDD. This frees up space in RAM to load
new application.
• OS constantly swap information back and forth
between RAM and HDD. This is called thrashing.
• The area of the HD that stores the RAM image is
called a page file.
Motherboard
• The main circuit board of a microcomputer.
• Contains the connectors for attaching additional
boards.
– CPU, BIOS, memory, mass storage interfaces, serial
and parallel ports, expansion slots
– all the controllers required to control standard
peripheral devices
• display screen, keyboard, and disk drive.
– Collectively, all these chips that reside on the
motherboard are known as the motherboard's
chipset.
Expansion slots
• ISA (Industry Standard Architecture)
• SIMM/DIMM (Single/Dual Inline Memory Module)
• PCI/PCI Express (Peripheral Component
Interconnect)
• AGP (Advanced graphic port)
• SCSI ( Small Computer System Interface)
• Cards
– Sound card, video card, colour card, network card
Ports & Connectors
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Parallel port
Com/Serial Port
IDE Drive connector
Floppy drive connector
USB connector
PS/2 connector
Secondary storage devices
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Magnetic Tape
Winchester/Hard Disk
Floppy Disk
Zip Disk
Jaz Disk
Super Disk
Optical Disk
– CDROM
– DVDROM
– Blue-Ray Disk
• USB Flash Drive
I/O Devices
• KBD, Mouse, Touch screen, light pen, track
ball, joystick, scanner, camera, microphone,
digitizing tablet, MIDI
• Monitor, MICR, OCR, OMR, Smart Card, Bar
Code Reader
• Printer
– Impact
– Non Impact
DATA
Raw material.
 Raw facts and figures

INFORMATION
Processed data.
 Organised data
 Which can be interpreted
Input
(Data)
Processing
(Software Instructions)

Output
(Information
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people
• Computers were designed by people and
occasionally maintained by people.
• Computers require people called users or
sometimes end users. They also need basic
computer literacy.
• People who learned the advanced features of
applications programs are called power users.
• Some people called Computer Professionals who
have taken intermediate and advanced courses in
computers.
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procedure
• Procedures are the steps that one must follow
to accomplish a specific computer-related
task.
• e.g. ATM is a computer. In response to the onscreen messages, called prompts, we insert
our card, enter our PIN, and tell the machine
how much money we want.
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