Class 1, 2-Merged
Class 1, 2-Merged
Class 1, 2-Merged
• Communication is unidirectional
• Only one of the two devices on a link can transmit; the other can only
receive
• Example : the keyboard can only introduce input, the monitor can only
accept output
Direction of Data flow (simplex, half-duplex, and full-duplex)
• Each station can both transmit and receive, but not at the same time
• The entire capacity of the channel is taken over by whichever of the two
devices is transmitting at that time
• Example : Walkie-talkies
Direction of Data flow (simplex, half-duplex, and full-duplex)
• The signals going in either direction share the capacity of the link
• The entire capacity of the link is reserved for transmission between those
two devices
Types of connections: point-to-point and multipoint
• Multipoint also called multidrop connection is one in which more than two
specific devices share a single link
The choice of one topology over another will have an impact on the:
Type of equipment the network needs.
Capabilities of the equipment.
Growth of the network.
Way the network is managed.
Categories of topology
A fully connected mesh topology (five devices)
Mesh topology
• These networks are expensive to install because they use a lot of cabling
• These networks are expensive to install because they use a lot of cabling
•Advantages
•Eliminates traffic problem
•Robust
•Private and secure
•Fault identification and fault isolation easy
•Disadvantages
•Since every device needs to be connected to each other, installation and
reconnection is difficult
•Sheer bulk of the wiring can be greater than the available space(in walls,
ceiling, floor)
•Hardware requirement to connect (i.e. I/O ports) can be expensive
A star topology connecting four stations
Star topology
•In the star topology, every device has a dedicated point-to-point link only
to a central controller called a hub.
•If one device wants to send data to another, it sends the data to the
controller, which then relays the data to the other connected device
•Advantages
•Less expensive than mesh topology
•Easy to install and reconfigure
•Less cabling needs to be housed
•Robust : If one link fails, only that link is affected, other links remain
active
•Fault identification and fault isolation easy
•Disadvantages
•Often more cabling is required in star than in other topologies
•Problem in hub incapacitates the whole setup
A bus topology connecting three stations
Terminator
Bus topology
• Sending the signal - Data in the form of electronic signals is sent to all the computers
on the network. Only the computer whose address matches the address encoded in the
original signal accepts the information. All other computers reject the data. Only one
computer at a time can send messages. Because only one computer at a time can send
data on a bus network, the number of computers attached to the bus will affect network
performance. The more computers there are on a bus, the more computers will be
waiting to put data on the bus and, consequently, the slower the network will be.
•Signal bounce - data, or electronic signal, is sent to the entire network, it travels from
one end of the cable to the other. If the signal is allowed to continue uninterrupted, it
will keep bouncing back and forth along the cable and prevent other computers from
sending signals. Therefore, the signal must be stopped after it has had a chance to reach
the proper destination address.
•Advantages
•Less expensive than mesh topology
•Easy to install and reconfigure
•Easy to add new devices
•Less cabling than mesh and star
•Disadvantages
•Difficult reconnection and fault identification
•Difficult to add new devices (degradation of signals)
•Fault or break in the bus incapacitates the whole setup
A ring topology connecting six stations
Ring topology
• In this topology, it forms a ring connecting devices with its exactly two
neighboring devices.
• A number of repeaters are used for Ring topology with a large number of
nodes, because if someone wants to send some data to the last node in the ring
topology with 100 nodes, then the data will have to pass through 99 nodes to
reach the 100th node. Hence to prevent data loss repeaters are used in the
network.
• To transmit the data, station has to hold the token. After the transmission is
done, the token is to be released for other stations to use. When no station is
transmitting the data, then the token will circulate in the ring.
•If one device does not receive a signal within a specified period, it can issue
an alarm.
Ring topology
•Advantages
•The possibility of collision is minimum in this type of topology
•Cheap to install and expand
•Easy to identify faults
•Disadvantages
•Unidirectional traffic
•A break in the ring disables the entire network
Tree topology
Advantages
1. It provides high scalability, as leaf nodes can add more nodes in the hierarchical
chain.
2. Other nodes in a network are not affected, if one of their nodes get damaged
3. It provides easy maintenance and fault identification.
4.Point-to-point wiring for individual segments.
Disadvantages
Characteristics of PAN
•It is mostly personal devices network equipped within a limited area.
•Allows you to handle the interconnection of IT devices at the surrounding of a single user.
PAN includes mobile devices, tablet, and laptop.
•It can be wirelessly connected to the internet called WPAN.
•Appliances use for PAN: cordless mice, keyboards, and Bluetooth systems.
Personal Area Network
Advantages of PAN
•PAN networks are relatively secure and safe
•It offers only short-range solution up to 10 m
•Strictly restricted to a small area
Disadvantages of PAN
•It may establish a bad connection to other networks at the same radio bands
•Distance limits
Local Area Network
Characteristics of LAN
•It is a private network, so an outside regulatory body never controls it.
•LAN operates at a relatively higher speed compared to other WAN systems.
•There are various kinds of media access control methods like Token Ring and Ethernet.
Local Area Network
Characteristics of MAN
•It mostly covers towns and cities in a maximum 50 km range
•Mostly used medium is optical fibers, cables
•Data rates adequate for distributed computing applications.
Metropolitan Area Network
Advantages of MAN
•It offers fast communication using high-speed carriers, like fiber optic cables.
•It provides excellent support for an extensive size network and greater access to
WANs.
•A MAN network mostly includes some areas of a city or an entire city.
Disadvantages of MAN
•You need more cable to establish MAN connection from one place to another.
•In MAN network it is tough to make the system secure from hackers
Wide Area Network
Characteristics of WAN:
•Any organization can form its global
integrated network using WAN.
Wide Area Network
Advantages of WAN
•WAN helps to cover a larger geographical area. Therefore business offices
situated at longer distances can easily communicate.
•Contains devices like mobile phones etc.
Disadvantage of WAN
•It is difficult to maintain the WAN network. You need skilled technicians and
network administrators.
•There are more errors and issues because of the wide coverage and the use of
different technologies.
•It requires more time to resolve issues because of the involvement of multiple
wired and wireless technologies.
•Offers lower security compared to other types of networks.
Internet, Intranet, Extranet
Workforce productivity. Intranets can help users to locate and view information faster and
use applications relevant to their roles and responsibilities.
Reduced Costs. This can potentially save the business money on printing, duplicating
documents, and the environment as well as document maintenance overhead.
Improved Communication. Intranets can serve as powerful tools for communication within
an organization.
Extranet
In some cases organizations make the decision to allow external parties such as customers
and suppliers to have access to their intranet. When these outside parties are provided
access to a subset of the information accessible from an organization’s intranet the intranet
becomes an extranet.
For example a large construction company may share drawings with architects or
inspectors, photographs to their customers and loan documents to their bankers by
implementing online applications that allow these external parties to access and even mark-
up and make changes to documents.
Build customer relationships. In business-to-business relationships, the more timely and accurate
information a business makes available to their customers, the more likely they are to retain that
business. Collaborate with other companies on joint development efforts.
Reduced margin of error. An extranet can reduce a company’s margin of error thereby reducing or
eliminating costly errors, especially with something as complex as processing orders from distributors
and suppliers. E.g. Customers can be given access to their accounts to verify order history, account
balances and payments.
Timely and accurate information. On an extranet a business can instantly change, edit, and update
sensitive information such as price lists or inventory information. Compared to typical paper-based
publishing processes, an extranet offers a unique opportunity to quickly get information into the right
hands before it’s out-of-date.
Reduced inventory. One of the greatest advantage of a business-to-business extranet is its impact on
supply-chain management. By linking the inventory system directly to a supplier, businesses can
process orders as soon as the system knows they are needed.
Flexibly. A well designed extranet allows remote and mobile staff to access core business information
24 hours a day, irrespective of location. This allows employees to work remotely or respond to critical
requests for information after normal working hours.
Differences
Client-Server Architecture
Service: any resource (e.g. data, file, control, display device, etc.)
•The IP address space (all possible IP values) is divided into five classes: A, B, C,
D, and E.
2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 2^7
128 64 32 16 8 4 2 1 128
1 1 1 1 1 1 1 1 1
128 64 32 16 8 4 2 1 128
255
________.________. ________.________
Decimal - 191.67.58.112
1*2^7+0*2^6+1*2^5+1*2^4+1*2^3+1*2^2+1*2^1+1*2^0
IP Addresses: Classful Addressing
•The IP address space (all possible IP values) is divided into five classes: A, B, C,
D, and E.
2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 2^7
128 64 32 16 8 4 2 1 128
1 1 1 1 1 1 1 1 1
128 64 32 16 8 4 2 1 128
255
________.________. ________.________
Decimal - 191.67.58.112
1*2^7+0*2^6+1*2^5+1*2^4+1*2^3+1*2^2+1*2^1+1*2^0
•Private addresses include IP addresses from the following subnets:
Range from 10.0. 0.0 to 10.255. 255.255 — Class A
Range from 172.16. 0.0 to 172.31. 255.255 — Class B
Range from 192.168. 0.0 to 192.168. 255.255 - Class C
• Once a domain has been established sub-domains can be created within the
domain.
EXAMPLE: The domain could be “amity.edu” and within this domain sub-
domains can be created for each university. E.g.: kol.amity.edu,
auup.amity.edu
• Syntax
– Structure or format of the data
– Indicates how to read the bits - field delineation
• Semantics
– Interprets the meaning of the bits
– Knows which fields define what action
• Timing
– When data should be sent and
– What speed at which data should be sent or speed at which it is
being received.
THE INTERNET
• Computers from different manufactures were unable to communicate with each other.
• The Advanced Research Projects Agency (ARPA) in the Department of Defense was
interested in finding a way to connect computers so that the researchers they funded
could share their findings.
• In 1967, ARPA presented its idea for ARPANET, a small network of connected
computers.
• In 1969, ARPANET was a reality, Software called the Network Control Protocol
(NCP) provided communication between hosts.
• In 1972 – 73, Vint Cerf and Bob Kahn, both of whom were part of the core ARPANET
group outlined protocols to achieve delivery of packets. The internetworking protocol s
are Transmission Control Protocol (TCP) and Internetworking Protocol (IP).
Hierarchical organization of the Internet
How is India connected to the internet?
More than 99% of the internet traffic relies on high quality fiber optic cables connecting
various countries. Only a part of the traffic goes through satellites.
These cable networks are laid and maintained by various governments and giant
companies.
How is India connected to the internet?
There are three tiers which differentiates the size of the network held by a company.
Tier-1 :- These are the companies which have a global network connecting so many cables
around the world. They will be able to provide access to any destination on the internet
without paying fee to others. They usually access the network of other tier-1 companies
without paying any fee. This network acts as the backbone of the internet.
Tier-2 :- These are companies which have a regional networks and are usually connected to
one or more tier-1 networks. They must pay a fee to access the tier-1 company's network.
Tier-3 :- These are the Internet Service Providers(ISPs) from whom we buy our broadband
connections. They are the last tier, connecting the internet to the end users.
India is connected to the world at Mumbai, Cochin, Chennai and Tuticorine. All our
international internet traffic goes through these port cities (landing stations).
Tata Communications owns 3 landing stations in Mumbai, Chennai and Cochin. They are the
only Tier-1 company from India.
Bharti Airtel owns 2 landings stations in Chennai and Mumbai.
Reliance Globalcom owns 1 landing station in Mumbai.
Sify Technologies owns 1 landing station in Mumbai
BSNL owns 1 landing station in Tuticorine connecting to Sri Lanka.
Online Privacy
Internet privacy is the privacy and security level of personal data published via the Internet.
It is a broad term that refers to a variety of factors, techniques and technologies used to
protect sensitive and private data, communications, and preferences. Internet privacy is also
known as online privacy.
Internet privacy is cause for concern for any user planning to make an online purchase, visit a
social networking site, participate in online games or attend forums. If a password is
compromised and revealed, a victim's identity may be fraudulently used or stolen.
• Each Nation sets their own laws on censorship of the internet. Some Nations
are stricter than others.
Guided media, which are those that provide a conduit from one
device to another.
Twisted-Pair Cable
Coaxial Cable
Fiber-Optic Cable
Twisted-pair cable
• Twisted pair is a physical media made up of a pair of cables twisted with each
other.
• A twisted pair cable is cheap as compared to other transmission media.
• Installation of the twisted pair cable is easy, and it is a lightweight cable.
• The degree of reduction in noise interference is determined by the number of
turns per foot. Increasing the number of turns per foot decreases noise
interference.
UTP and STP cables
Unshielded Twisted Pair
Advantages
•The cost of the shielded twisted pair cable is not very high and not very low.
•An installation of STP is easy.
•It has higher capacity as compared to unshielded twisted pair cable.
Disadvantages
•It is more expensive as compared to UTP and coaxial cable.
•It has a higher attenuation rate.
Coaxial cable
Coaxial cable
•Fiber optic is a cable that holds the optical fibers coated in plastic that are
used to send the data by pulses of light.
•The plastic coating protects the optical fibers from heat, cold,
electromagnetic interference from other types of wiring.
•Fiber optics provide faster data transmission than copper wires.
Bending of light ray
Optical fiber
•Core: The optical fiber consists of a narrow strand of glass or plastic known as a
core. A core is a light transmission area of the fiber. The more the area of the core,
the more light will be transmitted into the fiber.
•Cladding: The concentric layer of glass is known as cladding. The main
functionality of the cladding is to provide the lower refractive index at the core
interface as to cause the reflection within the core so that the light waves are
transmitted through the fiber.
•Jacket: The protective coating consisting of plastic is known as a jacket. The
main purpose of a jacket is to preserve the fiber strength, absorb shock and extra
fiber protection.
Optical fiber
Characteristics of Microwave:
•Frequency range: The frequency range of terrestrial microwave is
from 4-6 GHz to 21-23 GHz.
•Bandwidth: It supports the bandwidth from 1 to 10 Mbps.
•Short distance: It is inexpensive for short distance.
•Long distance: It is expensive as it requires a higher tower for a
longer distance.
•Attenuation: Attenuation means loss of signal. It is affected by
environmental conditions and antenna size.
Unidirectional antennas
Microwaves
Advantages Of Microwave:
•Microwave transmission is cheaper than using cables.
•It is free from land acquisition as it does not require any land for the installation of
cables.
•Microwave transmission provides an easy communication in terrains as the installation of
cable in terrain is quite a difficult task.
•In this case, antennas are mounted on the towers to send a beam to another
antenna which is km away.
•It works on the line-of-sight transmission, i.e., the antennas mounted on the towers
are the direct sight of each other.
Satellite Microwave Transmission
Characteristics Of Infrared:
•It supports high bandwidth, and hence the data rate will be very high.
•Infrared waves cannot penetrate the walls. Therefore, the infrared
communication in one room cannot be interrupted by the nearby rooms.
•An infrared communication provides better security with minimum
interference.
•Infrared communication is unreliable outside the building because the sun rays
will interfere with the infrared waves.
Virtual private network
Addressing in a VPN
Addressing in a VPN
Module 5
Database Management System
Data, Information & Knowledge
• Controlling Redundancy
• Integrity can be enforced
• Inconsistency can be avoided
• Accessing data through DBMS is easy
• Data can be Shared
• Standards can be enforced
• Restricting unauthorized access
• Concurrency anomalies can be reduced
• Providing Backup and Recovery
Organizing Data
• Super Key: is a set of one or more attributes that, taken collectively, allow
us to identify uniquely a tuple in the relation.
• Primary Key: although several candidate keys may exist, one of the
candidate keys is selected by a designer as the principal means of
identifying tuples within a relation.
• Foreign Key: A relation say r1, may include among its attributes the
primary key of another relation schema, say r2. This attribute is called the
foreign key from r1, referencing r2.
Enroll No Name Address Ph No Dept
Super Key –
Candidate key –
Primary key –
Alternate key/Secondary key –
Unique -
Foreign Key
Enroll No Name Address Ph No Dept
Foreign Key
SQL – Structured Query Language
Constraints used in SQL
• NOT NULL: That indicates that the column must have some value and
cannot be left NULL.
• UNIQUE: This constraint is used to ensure that each row and column has a
unique value, and no value is being repeated in any other row or column.
• PRIMARY KEY: This constraint is used in association with NOT NULL and
UNIQUE constraints such as on one or the combination of more than one
column to identify the particular record with a unique identity.
Example:
Like entities, a relationship too can have attributes. These attributes are called
descriptive attributes.
Roles
• Entity sets of a relationship need not be distinct
• The labels “manager” and “worker” are called roles; they
specify how employee entities interact via the works_for
relationship set.
• Roles are indicated in E-R diagrams by labeling the lines that
connect diamonds to rectangles.
• Role labels are optional, and are used to clarify semantics of the
relationship
Mapping Cardinality Constraints
Total participation (indicated by double line): every entity in the entity set
participates in at least one relationship in the relationship set
E.g. participation of loan in borrower is total
every loan must have a customer associated to it via borrower
Partial participation: some entities may not participate in any relationship in the
relationship set
Example: participation of customer in borrower is partial
Alternative Notation for Cardinality Limits
Cardinality limits can also express participation constraints
E-R Diagram with a Ternary
Relationship
Cardinality Constraints on Ternary
Relationship
• We allow at most one arrow out of a ternary (or greater
degree) relationship to indicate a cardinality constraint
• E.g. an arrow from works_on to job indicates each
employee works on at most one job at any branch.
• If there is more than one arrow, there are two ways of
defining the meaning.
– E.g. a ternary relationship R between A, B and C with arrows to B
and C could mean
1. each A entity is associated with a unique entity from B and C
or
2. each pair of entities from (A, B) is associated with a unique C
entity, and each pair (A, C) is associated with a unique B
– Each alternative has been used in different formalisms
– To avoid confusion we outlaw more than one arrow
Weak Entity Sets
• An entity set that does not have a primary key is referred to as a
weak entity set.
• The existence of a weak entity set depends on the existence of a
identifying entity set
– it must relate to the identifying entity set via a total, one-to-many
relationship set from the identifying to the weak entity set
– Identifying relationship depicted using a double diamond
• The discriminator (or partial key) of a weak entity set is the set
of attributes that distinguishes among all the entities of a weak
entity set.
• The primary key of a weak entity set is formed by the primary
key of the strong entity set on which the weak entity set is
existence dependent, plus the weak entity set’s discriminator.
Weak Entity Sets (Cont.)
• We depict a weak entity set by double rectangles.
• We underline the discriminator of a weak entity set with a
dashed line.
• payment_number – discriminator of the payment entity set
• Primary key for payment – (loan_number, payment_number)
Extended E-R Features: Specialization
• E-commerce uses the internet to connect with the rest of the world. In
contrast to E-business, internet, intranet and extranet are used for
connecting with the parties.
Advantages of E-commerce
– Technical
– Non-technical
Technical Limitations
• There can be lack of system security, reliability or standards owing to poor
implementation of e-commerce.
• User resistance: Users may not trust the site being an unknown faceless
seller. Such mistrust makes it difficult to convince traditional users to switch
from physical stores to online/virtual stores.
• Internet access is still not cheaper and is inconvenient to use for many
potential customers, for example, those living in remote villages.
The dimensions of E-Commerce
• A product may be physical or digital
• The process may be physical or digital
• The delivery method may be physical or digital
A website following the B2C business model sells its products directly to a
customer. A customer can view the products shown on the website. The
customer can choose a product and order the same. The website will then
send a notification to the business organization via email and the
organization will dispatch the product/goods to the customer.
Flipkart.com, Yebhi.com, Myntra.com, Zovi.com etc
Business – to – Business – to - Consumer (B2B2C)
A website following the C2C business model helps consumers to sell their
assets like residential property, cars, motorcycles, etc., or rent a room by
publishing their information on the website. Website may or may not
charge the consumer for its services. Another consumer may opt to buy
the product of the first customer by viewing the post/advertisement on
the website.
Quikr.com, OLX.com etc.
Consumer - to - Business (C2B)
• E-Help - E-Help refers to general help line number. It includes the use of
technologies like internet, SMS, etc. for the purpose of reducing the
response time of the Government agencies to the people queries and at
the time of disasters. “Women Help line number – 1091”, “Child Help Line
Number -1098 ” The role of NGOs is also vital in helping the Government
during the time of disasters.
Citizen - to - Government (C2G)
G2G relationship would include the relationships between Central and State
Government and also the relationship between two or more Government
departments
• E-administration - E-administration would include the implementation of IT in the
functioning of the Government, internally and externally. E-administration can
substantially reduce paperwork if properly used. E-administration will also bring
transparency to the administration of Government Departments.
• E-police - The concept of E-police includes databases of Police Officers, their
performances; Criminals databases. This is little different from Cyber-Police. Cyber
Police require technology experts to curb the electronic crimes. Whereas e-police
inclined to reduce the response time of police department when approached by
public.
• E-courts - The concept of E-Court will include the IT enablement of the judicial
process. This will ultimately decrease the time delay in hearing a case. Details
regarding the cases can be seen online, even though it’s there in current scenario
but it’s not effectively followed. Government must see the ways and means
through which this can be implemented effectively.
Government - to - Business (G2B)
E-commerce can be done not only between business partners but also within
organizations. Such activity is referred to as Intrabusiness EC or in short,
Intrabusiness.
Intrabusiness can be done between a business and its employees (B2E),
among units within the business (usually done as collaborative commerce), and
among employees in the same business.
Companies are finding many ways to do business electronically with their own
employees. They disseminate information to employees over the company
intranet, e.g. they also allow employees to manage their fringe benefits and take
training classes electronically. In addition, employees can buy discounted
insurance, travel packages, and tickets to events on the corporate intranet, and
they can electronically order supplies and material needed for their work. Also,
many companies have electronic corporate stores that sell the company's products
to its employees, usually at a discount.
Revenue Model
A firm’s revenue model describes how the firm will earn revenue, generate
profits, and produce a superior return on invested capital.
Minimum transfer
Rs.1 Rs.2 lakh Rs.1
value
Maximum transfer
Rs.2 lakh Rs.10 lakh Rs.2 lakh
value
One-on-one One-on-one
Type of settlement Batches
settlement settlement
Within 2 hours
Speed of settlement (subject to cut-off Immediately Immediately
timings and batches)
• Insta Alerts : Customers receive timely alerts in the form of SMS or emails, which helps to
keep track of financial transactions.
• Security Solutions : Banking systems are secured using state-of-the-art security solutions
such as firewalls, intrusion detection systems, intrusion prevention systems and anti-
malware systems.
• Cooling Period : Fund Transfer can only be made to the beneficiaries that are added by
the Customer. The customer can transfer funds to the payee only after a 30 minutes
cooling period.
• CAPTCHA Implementation : To safeguard the customer from password guessing attack on
their customer id, bank has implemented CAPTCHA solution.
• Last Login : Every user is given an indication of his last login, which helps him to analyse.
• Mobile Number Masking : To avoid unnecessary risk, only the last digits of a user’s
mobile number is displayed in SMSs.
Electronic Payment Systems
E-Commerce sites use electronic payment where electronic payment
refers to paperless monetary transactions. Electronic payment has
revolutionized the business processing by reducing paper work,
transaction costs, labour cost. Some of the modes of electronic payments
are following.
• Credit Card
• Debit Card
• Smart Card
• E-Wallet
• Electronic Fund Transfer (EFT)
• Unified Payment Interface (UPI)
Credit Card
Payment using credit card is one of most common mode of electronic
payment. Credit card is small plastic card with a unique number attached
with an account. It has also a magnetic strip embedded in it which is used
to read credit card via card readers. When a customer purchases a product
via credit card, credit card issuer bank pays on behalf of the customer and
customer has a certain time period after which he/she can pay the credit
card bill. It is usually credit card monthly payment cycle.
E-Money
E-Money transactions refers to situation where payment is done over
the network and amount gets transferred from one financial body to
another financial body without any involvement of a middleman. E-
money transactions are faster, convenient and saves a lot of time.
Online payments done via credit card, debit card or smart card are
examples of e-money transactions.
Electronic Fund Transfer
It is a very popular electronic payment method to transfer money from
one bank account to another bank account. Accounts can be in same bank
or different bank. Fund transfer can be done using ATM (Automated Teller
Machine) or using computer.
Now a days, internet-based EFT is getting popularity. In this case,
customer uses website provided by the bank. Customer logins to the
bank's website and registers another bank account. He/she then places a
request to transfer certain amount to that account. Customer's bank
transfers amount to other account if it is in same bank otherwise transfer
request is forwarded to ACH (Automated Clearing House) to transfer
amount to other account and amount is deducted from customer's
account. Once amount is transferred to other account, customer is
notified of the fund transfer by the bank.
Unified Payment Interface (UPI)
A Unified Payment Interface (UPI) is a single window mobile payment
system launched by the National Payments Corporation of India (NPCI).
The system is designed to provide a simple, secure and convenient “single
interface” to enable sending and receiving of money using smartphones
through a "single identifier" which can be a virtual address like an email
ID, mobile number. It eliminates the need to enter bank details or other
sensitive information each time a customer initiates a transaction.
• Adware – is typically used to call for pop-up ads to display when the user
visits certain sites.
• Browser parasite - is a program that can monitor and change the settings
of a user’s browser, for instance, changing the browser’s home page, or
sending information about the sites visited to a remote computer. Browser
parasites are often a component of adware.
(Lenovo faced huge criticisms when it became known that, since
September 2014, it had been shipping its Windows laptops with Superfish
adware preinstalled.)
• white hats - “good” hackers who help organizations locate and fix security flaws
• black hats - hackers who act with the intention of causing harm
• grey hats - hackers who believe they are pursuing some greater good by breaking
in and revealing system flaws. Their only reward is the prestige of discovering the
weakness.
Module 1
SSI(Small Scale Integration ) —10–100 transistors/chip
MSI(Medium Scale Integration ) —100–1000 transistors/chip
LSI(Large Scale Integration ) —1000–10,000 transistors/chip
VLSI( Very Large Scale Integration ) —10,000–1,00,000 transistors/chip
ULSI( Ultra Large Scale Integration ) —10 ^ 6 –10 ^ 7 transistors/chip
GSI( Giant Scale Integration ) — greater than 10 ^ 7 transistors/chip
Categories of Computers and Computer Systems
• Computers are classified into two:
• A special-purpose computer
• A general-purpose computer
Special-Purpose Computers
• Is a computer designed for a particular function, executing the same stored
set of instructions whenever requested.
• For example
• microwave ovens
• washing machine
• medical diagnostic equipment
Categories of Computers and Computer Systems
General-Purpose Computers
• Is a computer that can be used for solving many different types of
problems.
• Available in many sizes and a wide range of capabilities.
• Can be classified as follows:
1. Microcomputers
a. Laptop computers
b. Desktop computers
c. Workstations
2. Minicomputers
3. Mainframe computers
4. Supercomputers
Classification of computers
based on size and type
Microcomputers
• Microcomputers are small, low-cost and
normally single-user digital computer.
• They consist of CPU, input unit, output unit,
storage unit and the software.
• Although microcomputers are stand-alone
machines, they can be connected to create
a network of computers that can serve
more than one user. IBM PC based on
Pentium microprocessor and Apple
Macintosh are some examples of
microcomputers.
• A workstation is the largest type of
microcomputer and is generally used in
scientific and engineering applications.
Netbook are smaller notebooks optimized
for low weight and low cost and are
designed for accessing web-based
applications.
Minicomputers
• Minicomputers are digital computers, generally used in
multi-user systems. They have high processing speed and
high storage capacity than the microcomputers.
Minicomputers can support many users simultaneously.
The users can access the minicomputer through their PCs
or terminal. They are used for real-time applications in
industries, research centers, etc.
• They are smaller and cheaper compared to mainframes.
• They can be server, which is used for managing internal
company networks or Web sites.
• Server computers are specifically optimized to support a
computer network enabling users to share files, software,
peripheral devices (such as printers), or other network
resources.
Mainframe Computer
• Human has emotions and creative thinking, but the computer does not have any
emotions neither has thinking capability.
• Humans grow day by day, but the computer does not grow.
• Computers need to be updated for better processing, but humans cannot be updated.
Applications of computer
Education Computers are extensively used, as a tool and as an aid, for imparting education.
Educators use computers to prepare notes and presentations of their lectures. Computers are
used to develop computer-based training packages, to provide distance education using the e-
learning software, and to conduct online examinations. Researchers use computers to get easy
access to conference and journal details and to get global access to the research material.
Entertainment Computers have had a major impact on the entertainment industry. The user can
download and view movies, play games, chat, book tickets for cinema halls, use multimedia for
making movies, incorporate visual and sound effects using computers, etc. The users can also
listen to music, download and share music, create music using computers, etc.
Sports A computer can be used to watch a game, view the scores, improve the game, play games
(like chess, etc.) and create games. They are also used for the purposes of training players.
Applications of computer
Advertising Computer is a powerful advertising media. Advertisement can be displayed on different websites,
electronic-mails can be sent and reviews of a product by different customers can be posted. Computers are also
used to create an advertisement using the visual and the sound effects. For the advertisers, computer is a
medium via which the advertisements can be viewed globally. Web advertising has become a significant factor in
the marketing plans of almost all companies. In fact, the business model of Google is mainly dependent on web
advertising for generating revenues.
Medicine Medical researchers and practitioners use computers to access information about the advances in
medical research or to take opinion of doctors globally. The medical history of patients is stored in the
computers. Computers are also an integral part of various kinds of sophisticated medical equipment's like
ultrasound machine, MRI scan machine, etc. Computers also provide assistance to the medical surgeons during
critical surgery operations like laparoscopic operations, etc.
Science and Engineering Scientists and engineers use computers for performing complex scientific calculations,
for designing and making drawings (CAD/CAM applications) and for simulating and testing the designs.
Computers are used for storing the complex data, performing complex calculations and for visualizing 3–
dimensional objects. Complex scientific applications like the launch of the rockets, space exploration, etc., are
not possible without the computers.
Applications of computer
Government The government uses computers to manage its own operations and for
e-governance. The websites of the different government departments provide
information to the users. Computers are used for the filing of income tax return,
paying taxes, online submission of water and electricity bills, for the access of land
record details, etc. The police department uses computers to search for criminals
using fingerprint matching, etc.
Home Computers have now become an integral part of home equipment. At home,
people use computers to play games, to maintain the home accounts, for
communicating with friends and relatives via Internet, for paying bills, for education
and learning, etc. Microprocessors are embedded in household utilities like, washing
machines, TVs, food processors, home theatres, security devices, etc.
• The memory is characterized based on
two key factors—capacity and access time.
• Capacity is the amount of information (in
Memory Hierarchy bits) that a memory can store.
• Access time is the time interval between the
read/ write request and the availability of
data. The lesser the access time, the faster is
the speed of memory.
• Ideally, we want the memory with fastest
speed and largest capacity. However, the
cost of fast memory is very high. The
computer uses a hierarchy of memory that
is organized in a manner to enable the
fastest speed and largest capacity of
memory.
• The internal memory and external
memory are the two broad categories of
memory used in the computer. The
internal memory consists of the registers,
cache memory and primary memory. The
internal memory is used by the CPU to
perform the computing tasks.
• The external memory is also called the
secondary memory. The secondary
memory is used to store the large amount
of data and the software.
Internal Memory
• The key features of internal memory are
(1) limited storage capacity,
(2) temporary storage,
(3) fast access, and
(4) high cost.
• Registers, cache memory, and primary memory constitute the internal memory.
• The primary memory is further of two kinds—RAM and ROM.
• Registers are the fastest and the most expensive among all the memory types. The registers are
located inside the CPU and are directly accessible by the CPU. The speed of registers is between
1—2 ns (nanosecond). The sum of the size of registers is about 200B.
• Cache memory is next in the hierarchy and is placed between the CPU and the main memory. The
speed of cache is between 2—10 ns. The cache size varies between 32 KB to 4MB.
• Any program or data that must be executed must be brought into RAM from the secondary
memory. Primary memory is relatively slower than the cache memory. The speed of RAM is
around 60ns.
Secondary Memory
• The key features of secondary memory storage devices are—
(1) very high storage capacity,
(2) permanent storage (non-volatile), unless erased by user,
(3) relatively slower access,
(4) stores data and instructions that are not currently being used by CPU but
may be required later for processing, and
(5) cheapest among all memory.
• The storage devices consist of two parts—drive and device. For
example, magnetic tape drive and magnetic tape, magnetic disk drive
and disk, and optical disk drive and disk. The speed of magnetic disk is
around 60ms. The capacity of a hard disk ranges from 10 GB to 1,600
GB (1.6 Tera Bytes).
Primary Memory
• Primary memory is the main memory of computer.
• It is a chip mounted on the motherboard of computer.
• Primary memory is categorized into two main types-
• Random Access Memory (RAM), and
• Read Only Memory (ROM)
Random Access Memory
• RAM is used to store data and instructions during the operation of
computer.
• RAM loses information when the computer is powered off. It is a volatile
memory.
• The size of RAM is limited due to its high cost. The size of RAM is measured
in MB or GB.
• The performance of RAM is affected by
• Access speed (how quickly information can be retrieved). The speed of RAM is
expressed in nanoseconds.
• Data transfer unit size (how much information can be retrieved in one request).
• RAM affects the speed and power of a computer. More the RAM, the better
it is. There are two categories of RAM, depending on the technology used to
construct a RAM— (1) Dynamic RAM (DRAM), and (2) Static RAM (SRAM).
Random Access Memory
• DRAM is the most common type of memory chip.
• DRAM is mostly used as main memory since it is small and cheap. It uses transistors and
capacitors. The transistors are arranged in a matrix of rows and columns. The capacitor holds
the bit of information 0 and 1. The transistor and capacitor are paired to make a memory cell.
The transistor acts as a switch that lets the control circuitry on the memory chip read the
capacitor or change its state.
• DRAM must be refreshed continually to store information. The refresh operation occurs
automatically thousands of times per second.
• DRAM is slow because the refreshing takes time. Access speed of DRAM ranges from 50 to
150 ns.
• SRAM chip is usually used in cache memory due to its high speed.
• SRAM uses multiple transistors (four to six), for each memory cell. It does not have a
capacitor in each cell.
• It does not need constant refreshing and therefore is faster than DRAM. SRAM is more
expensive than DRAM, and it takes up more space.
• The access speed of SRAM ranges from 2– 10 nanosecond.
Read Only Memory
• ROM is a non-volatile primary memory. It does not lose its content when
the power is switched off. The features of ROM are described as follows—
• ROM, as the name implies, has only read capability and no write capability.
After the information is stored in ROM, it is permanent and cannot be
corrected.
• ROM comes programmed by the manufacturer. It stores standard
processing programs that permanently reside in the computer. ROM stores
the data needed for the start up of the computer. The instructions that are
required for initializing the devices attached to a computer are stored in
ROM.
Read Only Memory
• The ROM memory chip stores the Basic Input Output System (BIOS). BIOS
provides the processor with the information required to boot the system. It
provides the system with the settings and resources that are available on
the system. BIOS is a permanent part of the computer. It does not load
from disk but instead is stored in a ROM memory chip. When the computer
is turned on, the BIOS does the following things—
• Power On Self Test (POST) is a program that runs automatically when the system is
booted. BIOS performs the power-on self-test. It checks that the major hardware
components are working properly.
• Bootstrap Loader is a program whose purpose is to start the computer software for
operation when the power is turned on. It loads the operating system into RAM and
launches it. It generally seeks the operating system on the hard disk. The bootstrap
loader resides in the ROM. The BIOS initiates the bootstrap sequence.
Read Only Memory
ROMs are of different kinds. They have evolved from the fixed read only memory to
the ones that can be programmed and re-programmed. They vary in the number of
re-writes and the method used for the re-writing. Programmable ROM (PROM),
Erasable Programmable ROM (EPROM) and Electrically Erasable Programmable
ROM (EEPROM) are some of the ROMs. All the different kinds of ROM retain their
content when the power is turned off.
• PROM can be programmed with a special tool, but after it has been programmed the
contents cannot be changed.
• EPROM can be programmed in a similar way as PROM, but it can be erased by exposing it to
ultraviolet light and re-programmed. EPROM chips have to be removed from the computer
for re-writing.
• EEPROM memories can be erased by electric charge and re-programmed. EEPROM chips do
not have to be removed from the computer for re-writing.
Flash Memory
• Flash Memory is a kind of semiconductor-based non-volatile, rewritable computer
memory that can be electrically erased and reprogrammed. It is a specific type of
EEPROM.
• It combines the features of RAM and ROM. It is a random-access memory, and its
content can be stored in it at any time. However, like ROM, the data is not lost when the
machine is turned off or the electric power is cut. Flash memory stores bits of data in
memory cells.
• Flash memories are high-speed memories, durable, and have low-energy consumption.
Since flash memory has no moving part, it is very shock-resistant. Due to these features,
flash memory is used in devices such as digital camera, mobile-phone, printer, laptop
computer, and record and play back sound devices, such as MP3 players.
Secondary Memory
• We saw that RAM is expensive and has a limited storage capacity. Since it is a volatile
memory, it cannot retain information after the computer is powered off. Thus, in
addition to primary memory, an auxiliary or secondary memory is required by a
computer. The secondary memory is also called the storage device of computer.
• The terms secondary memory and storage device are used interchangeably. In
comparison to the primary memory, the secondary memory stores much larger amounts
of data and information The data and instructions stored in secondary memory must be
fetched into RAM before processing is done by CPU.
• Magnetic tape drives, magnetic disk drives, optical disk drives and magneto-optical disk
drives are the different types of storage devices.
• ACCESS TYPES OF STORAGE DEVICES - The information stored in storage devices can be
accessed in two ways—
• Sequential access
• Direct access
Sequential and Direct Access
• Sequential Access Devices
Sequential access means that computer must run through the data in
sequence, starting from the beginning, in order to locate a particular
piece of data. Magnetic tape is an example of sequential access device.
Let us suppose that magnetic tape consists of 80 records. To access the
25th record, the computer starts from first record, then reaches
second, third etc. until it reaches the 25th record. Sequential access
devices are generally slow devices.
• Let’s say that an operating system needs 120 MB of memory in order to hold all the running
programs, but there’s currently only 50 MB of available physical memory stored on the RAM chips
• The operating system will then set up 120 MB of virtual memory, and will use a program called the
virtual memory manager (VMM) to manage that 120 MB
• The VMM will create a file on the hard disk that is 70 MB (120 – 50) in size to account for the extra
memory that’s needed
• The O.S. will now proceed to address memory as if there were actually 120 MB of real memory
stored on the RAM, even though there’s only 50 MB
• The VMM creates a file on the hard disk that holds the extra memory that is needed by the O.S., for
example 70 MB in size
• This file is called a paging file (also known as a swap file) and plays an important role in virtual
memory
HOW VIRTUAL MEMORY WORKS
• The paging file combined with the RAM accounts for all the memory.
• Whenever the O.S. needs a ‘block’ of memory that’s not in the real (RAM) memory, the VMM takes
a block from the real memory that hasn’t been used recently, writes it to the paging file, and then
reads the block of memory that the O.S. needs from the paging file.
• The VMM then takes the block of memory from the paging file and moves it into the real memory –
in place of the old block. – This process is called swapping (also known as paging), and the blocks
of memory that are swapped are called pages.
• There are two reasons why virtual memory is important – to allow the use of programs that are too
big to physically fit in memory – to allow for multitasking – multiple programs running at once
• Before virtual memory existed, a word processor, e-mail program, and browser couldn’t be run at
the same time unless there was enough memory to hold all three programs at once
• This would mean that one would have to close one program in order to run the other, but now with
virtual memory, multitasking is possible even when there is not enough memory to hold all
executing programs at once.
An instruction in a computer program that causes
processing to move to a different place in the program
sequence. ... 'A jump instruction is added to the end of
the modified program codes in the RAM, so that after the
modified program codes are executed, the operation is
returned to the ROM.
https://en.wikipedia.org/wiki/Booting
When you power on a computer, it goes through a “boot up” process– a term that comes from the word
“bootstrap.”
• When you press the power button, the computer supplies power to its components—the motherboard,
CPU, hard disks, solid state drives, graphics processors, and everything else in the computer.
• Now that it has electricity, the CPU initializes itself and looks for a small program that is typically stored in
ROM on the motherboard i.e., BIOS (Basic Input/Output System) or UEFI (Unified Extensible Firmware
Interface). The BIOS or UEFI firmware loads configuration settings backed up by a CMOS battery.
• The CPU runs the UEFI or BIOS, which tests and initializes your system’s hardware—including the CPU itself.
For example, if your computer doesn’t have any RAM, it will beep and show you an error, stopping the boot
process. This is known as the POST (Power On Self Test) process.
• After it’s done testing and initializing your hardware, the UEFI or BIOS will hand off responsibility for booting
your PC to your operating system’s boot loader.
• The UEFI or BIOS looks for a “boot device” to boot your operating system from. This is usually your
computer’s hard disk or solid-state drive, but may also be a CD, DVD, USB drive, or network location. The
boot device is configurable from within the UEFI or BIOS setup screen. If you have multiple boot devices, the
UEFI or BIOS attempts to hand off the startup process to them in the order they’re listed.
• Traditionally, a BIOS looks at the MBR (master boot record), a special boot sector at the beginning of a disk.
The MBR contains code that loads the rest of the operating system, known as a “bootloader.” The BIOS
executes the bootloader, which takes it from there and begins booting the actual operating system—
Windows or Linux, for example.
• The bootloader is a small program that has the task of booting the rest of the operating system. Windows
uses a bootloader named Windows Boot Manager (Bootmgr.exe), most Linux systems use GRUB(GRand
Unified Bootloader), and Macs use something called boot.efi.
• If there’s a problem with the bootloader—for example, if its files are corrupted on disk—you’ll see a
bootloader error message, and the boot process will stop.
• On Windows, the Windows Boot Manager finds and starts the Windows OS Loader. The OS loader loads essential hardware drivers
that are required to run the kernel—the core part of the Windows operating system—and then launches the kernel. The kernel then
loads the system Registry into memory and loads any additional hardware drivers that are marked with “BOOT_START,” which means
they should be loaded at boot. The Windows kernel then launches the session manager process (Smss.exe), which starts the system
session and loads additional drivers. This process continues, and Windows loads background services as well as the welcome screen,
which lets you sign in.
• On Linux, the GRUB boot loader loads the Linux kernel. The kernel also starts the init system—that’s systemd on most modern Linux
distributions. The init system handles starting services and other user processes that lead all the way to a login prompt.
TYPES OF SOFTWARE
System software provides basic functionality to the computer. System software is required for the working of
computer itself. The user of computer does not need to be aware about the functioning of system software, while
using the computer. For example, when you buy a computer, the system software would also include different
device drivers. When you request for using any of the devices, the corresponding device driver software
interacts with the hardware device to perform the specified request
The purposes of the system software are:
• To provide basic functionality to computer,
• To control computer hardware, and
• To act as an interface between user, application software and computer hardware. System
Software
• It manages different resources of the computer like the CPU time, memory space, file storage, I/O devices etc.
During the use of computer by other programs or users, operating system manages various resources and allocates
them whenever required, efficiently.
• It provides a convenient interface to the user in the form of commands and graphical interface, which facilitates the
use of computer.
Device Driver
A device driver acts as a translator between the hardware and the software that uses the devices. It intermediates
between the device and the software, in order to use the device.
The device driver software is typically supplied by the respective device manufacturers.
Nowadays, the operating system comes preloaded with some commonly used device drivers, like the device
driver for mouse, webcam, and keyboard. The device drivers of these devices are preinstalled on the computer,
such that the operating system can automatically detect the device when it is connected to the computer. Such
devices are called plug and play devices. In case the computer does not find the device driver, it prompts the
user to insert the media (like a CD which contains the corresponding device driver).
Device drivers can be character or block device drivers. Character device drivers are for character-based devices
like keyboard, which transfer data character by character. Block device driver are for devices that transfer data
as a block, like in hard disk.
System Utilities
System utility software is required for the maintenance of computer. System utilities are used for supporting and enhancing the
programs and the data in computer. Some system utilities may come embedded with OS and others may be added later. Some examples
of system utilities are:
• Disk Compression utility to compress contents of a disk for increasing the capacity of a disk.
• Disk Partitioning to divide a single drive into multiple logical drives. Each drive is then treated as an individual drive and has its
own file system
• Disk Cleaners to find files that have not been used for a long time. It helps the user to decide what to delete when the hard disk is
full.
• Backup Utility to make a copy of all information stored on the disk. It also restores the backed-up contents in case of disk failure.
• System Profiling Utility provides detailed information about the software installed on the computer and the hardware attached to it.
Software trends have been away from custom-designed one-of-kind programs developed by the professional
programmers or end users of an organization toward the use of off-the-shelf software packages acquired by end users
from software vendors.
1. Vertical packages - assist users within a specific industry segment. Examples include packages that help to
manage construction projects, keep track of inventory of hospitals, or fast-food outlets.
2. Horizontal packages - can perform a certain general function, such as accounting, or office automation, for a
range of businesses.
• CREDIT CARD FRAUD/THEFT –
Theft of credit card data is one of the most feared occurrences on the
Internet. Fear that credit card information will be stolen prevents users
from making online purchases in many cases.
• IDENTITY FRAUD –
It involves the unauthorized use of another person’s personal data, such as
pan number, aadhar number, social security, driver’s license, and/or credit
card numbers, as well as user names and passwords, for illegal financial
benefit. Cybercriminals employ many of the techniques described
previously, such as spyware, phishing, and credit card theft, for the
purpose of identity fraud.
• SPOOFING –
It involves attempting to hide a true identity by using someone else’s e-
mail or IP address.
• PHARMING –
Automatically redirecting a web link to an address different from the
intended one, with the site masquerading as the intended destination
• DENIAL OF SERVICE (DOS) AND DISTRIBUTED DENIAL OF SERVICE (DDOS)
ATTACKS –
Hackers flood a website with useless pings or page requests that
overwhelm the site’s web servers. DoS attacks involve the use of bot
networks. DoS attacks typically cause a website to shut down, making it
impossible for users to access the site. For busy e-commerce sites, these
attacks are costly; while the site is shut down, customers cannot make
purchases. And the longer a site is shut down, the more damage is done to
a site’s reputation. Although such attacks do not destroy information.
Distributed Denial of Service (DDoS) attack using numerous computers to
attack the target network from numerous launch points.
• SNIFFING –
It is a type of eavesdropping program that monitors information traveling
over a network. Sniffers enable hackers to steal information from
anywhere on a network, including passwords, e-mail messages, company
files, and confidential reports.
• INSIDER ATTACKS –
The largest financial threats to business institutions come not from
robberies but from misuse by insiders. Some of the largest disruptions to
service, destruction to sites, and diversion of customer credit data and
personal information have come from insiders—once trusted employees.
Employees have access to privileged information, and, in the presence of
sloppy internal security procedures, they are often able to roam
throughout an organization’s systems without leaving a trace.
• Islands of automation
1. The Cost
If you choose to invest in a traditional ERP system, you could quickly spend five figures for a single license. For many, this
is by far the most significant disadvantage of ERP software. The cost of the software alone can be prohibitively high,
especially for small-to-medium-sized businesses. SMBs can avoid the upfront costs with a cloud solution.
4. Slow Implementation
A new ERP system implementation is a time-consuming
process, especially if you’re using obsolete hardware. It can
take as long as two years for ERP software installation.
Hidden Costs of ERP
• Training
• Testing
• Data conversion
• Consultants
• Employing best and brightest staff after
implementation
An ERP Example: Before ERP
Orders
Parts
Sends report Customer
Demographic
Sales Dept. Files Customers
Checks for Parts
Calls back “Not in stock”
Accounting “We ordered the parts”
Files
Accounting
Sends report
Invoices
Sends report
accounting
Ships parts
Vendor
Warehouse
Order is placed “We Need parts #XX”
with Vendor
Inventory
Purchasing Files
Files “We ordered the parts”
Purchasing
An ERP Example: After ERP
Orders
Parts Inventory Data
If no parts,
order is placed
Customers Sales Dept. through DB Accounting
Order is submitted
to Purchasing. Database
Purchasing record Books inventory
order in DB against PO
Order is placed
with Vendor
Warehouse
Vendor Purchasing
Ships parts
And invoices accounting
ERP and related technologies
1. BUSINESS PROCESS RE-ENGINEERING (BPR)
2. MANAGEMENT INFORMATION SYSTEMS (MIS)
3. DECISION SUPPORT SYSTEMS (DSS)
4. EXECUTIVE INFORMATION SYSTEMS (EIS)
5. DATA WAREHOUSING
6. DATA MINING
7. ON-LINE ANALYTICAL PROCESSING (OLAP)
8. SUPPLY CHAIN MANAGEMENT(SCM)
ERP and related technologies
1. BUSINESS PROCESS RE-ENGINEERING (BPR)
2. MANAGEMENT INFORMATION SYSTEMS (MIS)
3. DECISION SUPPORT SYSTEMS (DSS)
4. EXECUTIVE INFORMATION SYSTEMS (EIS)
5. DATA WAREHOUSING
6. DATA MINING
7. ON-LINE ANALYTICAL PROCESSING (OLAP)
8. SUPPLY CHAIN MANAGEMENT(SCM)
Business Process Re-engineering(BPR)
Data Mart: Departmental subsets that focus on selected subjects. A data mart is a
segment of a data warehouse that can provide data for reporting and analysis on a section,
unit, department or operation in the company, e.g. sales, payroll, production.
Data Mining
• DM is the process of identifying valid, novel, potentially useful and
ultimately comprehensive knowledge from database that is used to
make crucial business decisions.
• Data mining techniques are used in many research areas. Web mining, a
type of data mining is used in customer relationship management(CRM),
takes advantage of the huge amount of information gathered by a
website to look for patterns in user behavior.
For example ; data mining software can help retail companies find
customers with common interest.
Architecture of a typical data mining
system
The difference
between a database and
a knowledge base is that
a database is a collection
of data representing facts
in their basic form, while
a knowledge base stores
information as answers to
questions or solutions to
problems. A knowledge
base allows for rapid
search, retrieval, and
reuse.
Three-tier data warehouse architecture
Online-Analytical Processing(OLAP)