SQl - Standard Query Language

 

  

    What do you mean by SQL   ?  

     SQL ore standard query language which is used to perform the basic CRUD

     function of managing a database like creating, updating, retreiving and deleting.

    Requirements fro running SQL :

     Basically we use SQL in building websites backend for fetching data from the 

     database. so we need the following technologies :

       1. We need a database program where we can run our queries like

             Ms Access, MySQL, Oracle.

       2.For styling of the website we need HTML/ CSS

       3. We need server side scripting Languages like PHP 

   So before Jumping to SQL we need to have brief  snapshot of what exactly is

   Database Management System:

   well as the name suggest that it is a platform where we can manage our data in

   flexible, reliable and error free manner. Basically Database is nothing but a table

   which contains data in the form of row and columns; lets visualize the components

   of database through a diagram.

  Let us see some basic SQL Statements used in Database:

    1. Select Query:

        Syntax 1: Select column1, column2, column3 from tablename;

        Function: The Select statement as the name suggests is used to select data according

                          to the specified criteria such as columns

    

  2.   Syntax 2: Select * from  tablename;

        Function: This query is used to fetch all the records from the table which are fed.

 

3.  Syntax 3: Select Distinct Column1, Column 2, Column 3  from tablename;

     Function: In order to fetch only different values  from the tables this statement

                       is used. In this query the basic objective is that to reduce same values

                      from appearing twice.

4.Syntax 4: Select Column1, Column2, Column3 from tablename where  condition;

Function: The where clause is used to filter records according to specified condition

5. Syntax 5: Select Column1, Column2, Column3 from tablename where

                     condition1 and condition2 and condition3;

Function: The And keyword used with where enable to filter data from database 

                  if all the conditions are true.

6. Syntax 6: Select Column1, Column2, Column3 from tablename where

                     condition1 or condition2 or condition3;

Function: The And keyword used with where enable to filter data from database 

                  if all the any one of the conditions are true.

7. Syntax 7:Select Column1, Column2,Column3 from tablename where NOT

                   Condition;

Function: The Not keyword is used to filter record from database excluding the

                   condition which is given in where clause.

 

8.Syntax 8:Select Column1, Column2, Column3 from tablename orderby columnname;

Function: The order by clause helps to display data from database according to ascending 

                 order or descending order alphabetically. By default the data is displayed in

                 ascending order. the keywords used to display in ascending is ASC and the

                 keyword used to display data in descending in DESC 

                   

 

 

 

  

  

 

   

Scheduling Algorithms in CPU

 

 

 

   

    What do you mean by CPU Scheduling ?

    

     CPU Scheduling deals with deciding of allocation of processes to the CPU which 

     are in the  ready queue.Basically this allocation is done with the help of certain

     algorithms. Scheduling Algorithms in CPU are of two types

    

       1 Preemptive Scheduling Algorithm: In this algorithm the CPU is allocated the

          process by the operating system with respect to its priority ie it does not wait

          for the process requests. This type of scheduling is useful for high priority

          process which requires immediate response. Examples are as follows:

                

                a. Round Robin Scheduling Algorithm

                b. Priority based scheduling

                c. Shortest Remaining Time  Next.

      2. Non Preemptive Scheduling Algorithm:This algorithm always process the 

          request according to the scheduled time. once a CPU has been allocated to

         a process it cannot be taken back until the process is executed.Examples are

         as follows:

 

                a. First come First serve

                b. Shortest Job First

  

    Performance evaluation of the Scheduling algorithm:

 

     From the many scheduling algorithms the performance of  the algorithms 

     depends basically on two factors:

       1. Maximum CPU Utilization

       2. Maximum Throughput

 

     Lets see it with the help of an example where we have the following five processes

     arrived at time 0.

 

    

Process	Processing Time
P1	10
P2	20
P3	03
P4	07
P5	12

 

           

 

 If we apply the FCFS algorithm for the set of process The Gantt Chart will be as follows:

                    P1            P2            P3        P4           P5 

              0         10                39         42         49           61

 

 

      Process                   Processing Time                   Waiting Time

    

         P1                                  10                                     0

         P2                                  29                                    10

         P3                                  03                                    39

         P4                                  07                                    42

         P5                                  12                                    49

     Average Waiting Time = (0+10+39+42+49)/5 = 28milliseconds

 

 

     Now if we consider the Shortest Job First  Scheduling Algorithm The Gantt

     Chart will be as follows:

      
                   P3            P4            P1       P5           P2 

              0         3               10            20         32           61

     
    Process                   Processing Time                   Waiting Time

    

         P1                                  10                                    10

         P2                                  29                                    32 

         P3                                  03                                    00

         P4                                  07                                    03

         P5                                  12                                   20

 

Average Waiting Time =(10+32+03+20)/5 = 13milliseconds 

 

Now if we compare average waiting time of above algorithm we see that SJF 

policy result in half of the average waiting time that has been allocated to FCFS.

           

         

    

  

   

 

Robots and Robotics!

    What is Robotics ?

      The branch of mechanical engineering, electrical engineering and computer

      science that deals with design, construction and operation of robots is called

      Robotics.A robot is thus a Programmed machine which reduce labour and

      manpower requirement.The term robot was coined by novelist and 

      playwright Karel Capek in the year 1920.

 

    Classification of Robots! 

     Robots are broadly classified into two categories. They are as follows!

     1.Industrial Robots- 

         These robots are basically used in manufacturing purposes such as 

         automotives Industries. These robots are programmed using computers.

    2. Service Robots:

         These  Robots are used for domestic and household purposes or in 

          restaurants for servicing customers etc etc.

     Robotics have paved the way for 21st century. It has helped in the development 

     of space probes that collect Information about the solar system .It has helped

     to closely study human brains . Emotion sensors have now been developed 

     that can now recognize the feeling of  a person with their  facial Expresions.

     these are robots with artificial Intelligence and programmed using super 

    computers.

     Androids :

     

         

When a robot is designed to execute highly sophisticated Instructions it is referred to 

as Android.

Android is a robot which is designed  to look and act like a human.These robots are

largely being seen in Science fiction movies.With the latest advancement of technology 

android robots have been modified to humanoid robots like Sophia the latest example

of humanoid robot.

Android also refers to Mobile operating system which is based on Linux.

it is primarily designed for touch screen mobile devices like smart phones

and Tablet computer.

 

Mechatronics:

 

  

  When mechanics and electronics are combined together it is known as Mechatronics.

  Robotics is exploring the possibility of helping physically challenged people to overcome

  the limitations for which mechatronics have played a vital role to assist people who have

 a problem with basic mobility.Mechatronics was coined by Tetsuro Moti in 1969 who was

  an engineering in Japanese Company

 

Transmission Control Protocol/Internet Control Protocol Model - TCP/IP Model

 

  What do you mean by TCP/IP Model ? 

   Transmission Control Protocol/Internet Protocol or TCP/IP Model is the

   newest layer developed and designed by Department of Defense in 1960

   for data communication between a network.  Majority of the Internet

   uses this protocol suite for sending and receiving message globally.

   Basically this Model is Composed of four layers which are as follows:

    1. Application Layer

    2. Transport Layer

    3. Internet layer

    4. Link Layer.

   we can summarize the diffrence between  OSI Model and TCP/IP model

   with a short diagram given below:

 

 

 

 

   Let us see the layers of TCP/IP in detail:

   1. Application Layer:This layer is the combination of Application, Presentation

       and Session Layer of the OSI Model. This layer allows users to Interact with

       the user. This layer is responsible for node to node communicaion in the

       network.

       The Protocols which are used in this layer are as follows:

         1. HTTP - Hyper Text Transfer Protocol

         2. HTTPS -Hyper Text Transfer Protocol Service

         3.SMTP: Simple Mail Transfer Protocol

         4. DNS: Domain Name System

         5. Telnet

2.Transport Layer: This layer functioning is similar to the working of the Transport

  layer of the OSI Model. This layer is also known as Host to Host layer as this

  layer is responsible for end to end delivery of data packets from sender to the 

 receiver without a single error.Basically two protocols are used in this layer

 which are given as follows:

  1. UDP - User Datagram Protocol(Connection less Protocol) 

  2. TCP - Transmission Control Protocol(Connection Oriented Protocol)

3. Internet Layer: This layer is similar to the functioning of Network layer

    of the OSI Model.This  layer is responsible for IP Addressing,Host to Host

    communication,Data Encapsulation and Routing.The Protocols which are

    used in this layer are as follows:

      1.IP- Internet Protocol

     2. ARP - Address Resolution Protocol

     3. ICMP: Internet Control Message Protocol

 

4.  Network Access Protocol: This layer is the combination of the Data Link Layer

    and Physical layer of the OSI Model.This layer is responsible for transmission

    of data in a network between same network, It basically determines how the data 

    should be sent Physically over  a network.The protocols which are used in this

   network are as follows:

    1. Ethernet

    2. Token Ring

    3. FDDI

 
 

  

   

Open System Interconnection Model-OSI Model

 

What is an OSI Model ?

OSI or Open System Interconnection Model was developed by International Organization  

for Standardization in the year 1984 for easy and reliable Network Communication.

In other words It can de said that this model basically facilitate to send and receive

messages from one computer to another computer in a network smoothly ans hassle free.

Basically OSI or Open System Interconnection is composed of Seven Layers to transmit 

data  from one computer to another across the globe

It may be noted that OSI layer is a reference layes in network communication and is 

and it is used practically to visualize and communicate how network operates.  

 

The layers  of OSI  Model  from the sender end is as follows:

1st Layer - Application layer:

2nd Layer- Presentation layer

3rd Layer - Session layer

4th Layer- Transportation layer

5th Layer- Network layer

6th layer- data Link layer

7th layer - Physical layer

 

The layers  of OSI  Model  from the receiver's end is as follows:

7th Layer - Application layer:

6th Layer- Presentation layer

5th Layer - Session layer

4th Layer- Transportation layer

3rd Layer- Network layer

2nd layer- data Link layer

1st layer - Physical layer

 

Let us see the OSI layers in detail:

Basically the OSI layer is practically divided into 2 layer

Upper layer: The upper layer is composition of Application layer,Presentation layer

                      and the Session layer. This layer is also called as software layer.

Lower layer: The Lower Later is a composition of  Physical layer, data link layer

                      and Network layer.

The Transport Layer is basically the Heart of the OSI  layer.

 

1. Physical Layer:This layer includes the Physical equipments included in data

    transfer from one computer to another computer such as  cables, switches. 

   In this layer the data get converted into bit stream.The Physical layers converts

   the data in the form of 0's and 1's and transmit it from one node to another.

   This layer is the lowest layer in the OSI reference model.

 

2. Data Link Layer:  The Data Link layer is responsible to convert the data in

    frames which it has received form Network layer. and send it from one computer

    to another computer in the same network.This layer is responsible error free

    transfer of data from one node to another using its MAC address of the nodes.

    The packets received from the Network layer are broken down into smaller  

     pieces called frames.The Data Link is composed of two sub parts:

     1.LLC- Logical Link Layer which is responsible for error free transmission

                   and synchronizing frames and managing protocols

     2.MAC- Media Access Control which is responsible for connecting devices

                    in a network and transmit and receive data

3. Network Layer:This Layer is similar to the Data link layer except that it is used

    to send data packets by breaking the segments received  from Transport layer

   from one node to send it to another node by reassembling it in receiver's ends

   in  different network.It sends packet by selecting the shortest  path which is 

   available  in the  Network,

4. Transport layer.This layer is also known as the Heart of the OSI layer. This layer

     is responsible for reliable and end to end delivery of the message This layer 

     receives the data and breaks it in form of segments at the sender's end.

    It also adds source and destination port number and  forward the segmented data

    to the Network layer.It is used fro checking error control if present and retransmit

    back to the source to send it again to the destination.

5. Session Layer:This layer is responsible for setting communication between two

    devices in a network.This layer ensures that the data is exchanged properly 

    between the two nodes during the ongoing session and then automatically closes

    the  session to avoid wastage of resources.

    The Session layer has also set benchmarks to  identify the errors and avoid premature

    loss of data if the session  is closed before delivery to receiver's end which is also

   known as Synchronization of data .

6. Presentation Layer;This layer is responsible for translation of data in the required

   format over the network and is also used for encryption and decryption of data 

   so that the data is end securely from sender's end to the receiver's end. It is also

   used to compress the data bits as per the requirement  of the receiver.

 

7. Application Layer: This layer is responsible for directly Interacting with the 

     user for the data using software application like Browsers, email , messengers.

     This layer is responsible for the protocols and data manipulation to present

     meaningful data to the user through the software applications.

  

 

  

 

 

 

 

Mobile IP and Mobile Communication Protocol

 

   What is Mobile IP ?

    Mobile IP is a protocol  that allows users to move from one network  to

    another network by maintaining the same IP address of the device to 

    enable transfer of  Information from one device to another . 

    It is an enhancement of Internet Protocol that diverts the internet traffic to 

    mobile devices. 

    Components of Mobile IP:

     In this section we are going to discuss about the components of Mobile IP

     They are as  follows:

     1. Mobile Network:

          It is basically the device that you carry with yourself for example your

          handheld devices Mobile Phones, Smart Phones.

    2.  Home Network:

          It is the Network to which the Mobile IP belongs(Home address)

    3.  Foreign Network:

         This is the network  which does not  belong to the Home Network.This

          Network is visited by Mobile Network.

    4. Correspondent Node:

         This is the adjacent node or Partner node to which Mobile Network 

         actually belongs, atleast one partner node is needed for communication.

    3. Care of Address(COA) :

         It basically defines the current .location of the Mobile Ip in which it

         is located. All the IP packets are delivered to this Mobile Network.

   4.  Home Agent:

        The Home Agent is basically the Mobile directory for the Home Network.

        It is present in the Home network which is the source of the Mobile Ip.

        It is the pathway for packets towards the Mobile Network. 

     5.Foreign Agents:

       The Foreign Agents act as  pathway endpoint for packet forwarding. It acts 

        as  a point of attachment for the Mobile node .

         The Mobile IP has basically Three Process. They are as follows:

     1. Agent Discovery

          In this the House  Agent and   Foreign Agent act as a Key Player.They

          rotate their services using the ICMP router.

     2. Registration

          This process basically forward packets to the Home network.The mobile node 

           registers its current location with the Foreign agent

     3. Tunneling :

           It is used to establish a tunnel or pathway between start and endpoint

          for packets.It is also known as port forwarding. 

 

Mobile Computing

 

    What do you mean by Mobile Computing ?

     Well Mobile Computing is a wireless technology used to transfer and share 

     voice , data, documents without being  connected  wirelessly with any device

     through  cables.It includes variety of devices which allows transmission of

     data and access information from wherever they are.

     Mobile devices can be connected either through LAN or any wireless Technology

     It is also used to transmit data through the data packs which they subscribe of 

     different ISP's(Internet Service Provider)  like Airtel, Vodafone, Jio etc.

 

     Components of Mobile Computing: 

      There are basically three  components of Mobile Computing.They are as

       follows:

       1. Mobile Hardware

       2. Mobile Software

       3.Mobile Communications

        Let us see the components in details:

       1.Mobile Hardware:

           These  includes the Physical devices  such as Tablets, Smartphones. PDA.

           They have receptors to sense signals and send and receive messages from 

           one device to the   another device.  

           When one device ends messages to the other device it need not wait for

           the acknowledgement and continously start executing another process.

   2.  Mobile Software:

         These are the programs which are being installed  in the Mobile Hardware 

         which help to perform the funtcions of Mobile computing in a swift and

         reliable way.The Operating system act as a catalyst to surface wireless

         communication in Mobile Computing. Some Operating system that are

         Installed in Mobile Devices are  Android,IOS,Blackberry, Windows Mobile.

 

    3. Mobile Communications: 

         It Includes protocols, services, bandwidth  services which ensures seamless

         communication in a network. It ensures that there is no collision with other

         systems that offer the same service.

    

    Benifits of Mobile Computing :

    The benifits of  Mobile Computing devices are as follows:

      1.Staying Connected for 24/7 hours

      2.Helps to  tailor Mobile Computing according to individual needs

      3. Flexibility and reliability in performing professional work    

 

 

    

 

   

 

 

Data Modeling:

 What is Data  Modelling ?

  Basically data model is the creation of a design or model fro storing data in a 

  database.Data models defines how the data is connected to each other 

  in the database  and how they are processed and utilized.

 Data models helps to ensure consistency thereby enabling quality of the data.

 Dat models helps to take proper business decisions, helps government in taking

 proper policy measures and also helps is regulatory compliances.

 

Basically There are Two Types of Data Models. They are as follows:

1. Entity Relationship Model:

2. UML(Unified Modelling Language)

 Let us understand them in details

1. Entity Relationship Model:

    It is based on real world entities and relationships among the entities.It is best

    used for conceptual design of the database. 

2. UML(Unifies Modelling Language):

     It is very important part in software development process. It basically represents

     the architecture or working of software or modules in graphical way.It helps

     the  software developers communicate, Validate and explore the architecture

    design of the software 

Types of Data Models:

There are three types of Data Models which are as follows:

1. Logical Model

2.Physical Model

3. Conceptual Model

Let us see this types in Details:

1.Logical data Model:

   It basically depends on the representation part of data model .It defines the structture

   and relationships between the data elements.At this model no primary or secondary 

   key  is defined.

2. Physical Data Model:

    It design  the internal schema of  databases. It includes, columns , tables and the

     relationships between these entities.It outlines the implementation methodology 

     like  Create, Retrieve, Update , Delete Operations on data.

  3. Conceptual data:

     This model is also called as Domain model.It basically defines what actually

      the system contains. It focuses on attributes and relation of the database.

      It is basically designed by business architect and stakeholders  and 

      basically used by business organisations.

 

 

 

 

 

Wireless Networks and Topologies;

 

 

 

 

 

    What do you mean by Wireless Network ?

     In wireless network computer, laptops, tablets and other devices are connected

     through network router than any usages of cables or wires  .

    In wi-fi based wireless network the access point or router act as an Ethernet switch

    All devices are directly connect to the router.

    The use of wireless networks to avoid costs of installing cables across the whole

    building. Generally wireless networks works with radio wave signals.

 

    Types of  Wireless  Networks :

     1.WPAN(Wireless Personal Area Network)

          Have a short range of 20-30 feet.Bluetooth is the best example which

          follows WPAN .

 2.   WLAN(Wireless Local Area Network)    :

        It extends  the communication to about 300ft and  consume  more  power.

 3: WMAN(Wireless Metropolitan Area Network):

       It ranges to a larger geographic area probably  city or suburb

4   WWAN(Wireless Wide Area Network):

     Provides connectivity over a large geographical area. These are networks used for 

     mobile phones and data service.

 

     Wireless Topologies:

     Basically  there   are  two  types  of wireless  topologies

        1. Infrastructure mode

        2. Independent  Basic Service Set(IBSS) 

     Let  us  understand  them  in detail:

      1. Infrastructure mode: It is also known as one to many topology. It has

          single  central  wireless  access points through  which  the  wireless

          client  connects  with  each  other .    

       2. Independent  Basic Service  Set(IBSS):In this topology  two  devices

           are connected  to  each  other wirelessly in a peer to peer  manner 

           without  the  use  of  an AP. It allows to  device  to  communicate

           with each other without  the  use of  any wireless device.

      

 

 

Communication Satellites

 

What do you mean by satellite communications ?

Satellite communications is one of the major developments in the field of

telecommunications Satellite Communications is the links to provide 

communications between various points in the earth.  These satellites uses

electromagnetic waves to carry the information in the form of audio, video,

voice or data between ground and space from any point in the earth.

How does a satellite works ?

A satellite is a communication system which has the ability to send signals 

to the earth and receive signals from the earth with the use of transponder

to send and receive radio signals. The frequency with which the signal is

sent into the space is known as uplink frequency and the frequency with 

which  the signal is sent by the transponder is known as Downlink frequency

Applications of Satellites:

Satellites are used in wide spread  way like Television. DTH, VSAT to exploit

the unique capabilities in terms of coverage and outreach .It is also used in

commercial basis over a large number of applications.The three types of

communication service that satellite  provides are:

1. Telecommunications

2. Broadcasting

3: Data Communications

Lets us see them in brief of what they are:

1. Telecommunication services: It includes all types of telephonic calls and

    services , wireless.mobiles and cellular network providers.

2. Broadcasting: It includes DTH or satellite television services like 

    DirecTV, DISH TV

3.Data Communications:  It involves transfer of data from one point to 

   another. Generally Financial Organisations and corporates uses 

  very small apperture terminal(VSAT) networks to facilitate Transfer of data

Development of satellite communication:

1. Sputnik 1 was the first artificial satellite launched successfully by the 

    Soviet Union  on October 4 1957

2. SCORE was the first voice signal satellite which was launched by the

   US  government on December 9 1958

3. APPLE was the first experimental communication satellite  successfully

     launched by Ariane -1 from Kouru, French Guiana on June 19.1981

Future of satellite Communication:

In the coming future satellite technology will have more processing

capabilities. more capacity and power,to  handle more bandwidth 

Communications satellites  have made internet access so easy

across each and every facets of  society

The demand for more  bandwidth with continuing development and 

innovation of satellite technology will ensure long term viability of 

satellite industry.

 

 

Mobile Technology

 

    Over the years we have seen that Mobiles have became an indispensible part our life.

    Starting from  general mobile  function such as calling and ending messages it has

    also played an important role in humans life of staying updated about latest news with

    one click using Touchscreen, Paying daily household bills, watching videos, 

    listening to songs , making videos and more

   In this article we are going to  understand about Mobile Technology and its different

   features.

 

  What is Mobile  Technology ? 

   Mobile Technology  is a  type of electronic portable  device which is used for

   cellular  communications, send and receive  messages, access social media

   platforms,discover  places  and  information, entertainment,shopping etc

   Mobile technology consists of  portable  two  way  communication device,

   computing  device and  the  networking  technology  that  connects them  

   Some of Mobile technology  devices  are  as  follows:

      1. Laptops and Tablets

      2. Smartphones

      3  Global  Positioning  Devices 

   

  Platforms on which Mobile Technology is based!

   There  are  two very Basic Technologies   on which Mobile Technology:

     GSM: Global System for Mobile Communications

     CDMA: Code Divison Multiple Access

   so let us undertsand in detail about GSM and CDMA:

     GSM: GSM or Global System for Mobile Communications  main characteristics

                 is that its is SIM specific meaning that the phone number si linked to the 

                 SIM card  so when you are switching the device all you need to do  is 

                 fetch out the SIM card and insert it into another device.    

                 All the information of the user are embedded in the  SIM card which 

                 the user is using 

                 The GSM association is an International association founded in 1987

                 with the goal  of developing and extending the GSM wireless standard.

                 GSM network uses TDMA(Time Division Multiple Access Technology)

                 which assigns time slots to multiple    conversations teams.alternating

                 them is sequence and  and switching between each conversations in

                 very small time slots.

                 Almost 80  -90%  of the world  populations  uses  GSM .It has

                 roaming accessibilities and uses GPRS which provides lower bandwidth

 

     CDMA: CDMA or  Code Division Multiple access  is a handset based standard

                   with a phone number linked to the specific device.if  you want  to 

                   upgrade with a another phone you would have to get in touch with

                   network carrier , de activate the old device and activate the new one.

                   CDMA networks layer digitized call over  one another, assigning unique

                   codes to differentiate  between them.Every call data is enclosed  with a 

                    different key and the calls are then transmitted at the same time.

                    each receiver have a unique key to  split the combined signals into

                    unique call.

                    CDMA uses EVDO which provides higher data bandwidth hence it has

                    faster transmission rate.

 

       GSM and CDMA are both  unique technologies. GSM technologies forms the basis 

       of 2G mobile phones whereas CDMA technology forms the basis for 3G mobile

       phones. Its upon the discretion of the user to use either GSM or CDMA.  

 

                      

       

 

 

 

Hadoop;

 

    What do  you mean  by  Hadoop ?

     Hadoop is a framework which is used to develop applications that could perform 

     complete statistical analysis in huge amount  of  data. It is a open source framework

     that is used in large datasets ranging from gigabytes to petabytes. It can handle various

     forms of structures and unstructured  data that  giving users more flexibility for

     collecting. processing, analyzing and maintaining data .

     It involves grouping multiple  computers in clusters to analyze datasets parellely

     and more quickly.

 

   A Brief History on Hadoop :  

   Hadoop was initially developed in 2005 by Apache  Software Foundation , 

   a non profit organization which develops open source software.

   Hadoop was name of the yellow toy elephant  owned  by son of its one of its

   Investors.In 2008 Yahoo released Hadoop as its open source project. 

 Importance of Hadoop:

  1. Store and Process huge amount of data quickly

  2. It is free and uses commodity hardware to store large amount of data

  3. Data and application processing are protected against hardware failure

  4. It stores and process structured and  unstructured data quickly and easily 

Hadoop Architecture

  Hadoop has four  core  modules which is included in the basic framework  

  by Apache Foundation:

    1. Hadoop Common: 

        It provides common java libraries that can be used across  all modules

   2. Hadoop Distributed File System:

       It is used for storing  data across  multiple  machines and

       provides better throughput than traditional file system, high fault tolerance

       and support  for  large  datasets.

  3. Yet Another Resource Negotiator:

       It helps  to manage resources  for the processes  running on the Hadoop

       It schedules  jobs and task.  

4.Map Reduce:

    It is a framework that helps programs to do parallel computation of data.

    It has basically two steps . In the first step  Mater node takes inputs and 

    partitions  them into smaller subprograms and then distributes  it to 

    sub nodes . After that the Master  nodes  takes the answers to all the

    sub problems and combines  them  to  produce  output. 

Environment Set Up for Hadoop :

  Hadoop is basically  supported by GNU/Linux environment.Therefore we have

  to  install Linux operating System  for setting up Hadoop Environment.

 If we different Operating System we can install virtual box and then install

 Linux in the virtual box.

 

  In Today's age where data has been increased at an mind boggling rate, Hadoop 

  has been successfully used by people  to  build  large  and  complex  applications.

  It has  also  met  the scalability requirements for large and varied amount of data .

 

 

 

 

Data Warehousing and Data Mining

 

      What do you mean by Data Warehousing ?

       Data Warehousing can be called as storage house of  data  where information

       from different places are stored in a huge database and then analyzed and

      corrected if any error is found.

      It is the electronic storage of large amount of data  by the business organization

      which is queried and analyzed. It is the process of transforming raw data into

      information and making it ready to be used by users 

   Characteristics of Data Warehouse

    1. The first important point to be seen that Data warehouses data are a 

         type of data which helps the organization to take  strategic and long

         term decisions.

  2.   It helps in historical analysis of data and come to a conclusion

  3.  These data are not  updated frequently unlike operational data

 

  Applications of Data Warehouse :

    1. Basically these type of data are used to take strategic Financial Decisions

    2. They are used by organizations to understand the tastes and preferences

         of the consumer goods.

    3. Banking Organizations. 

  What do you mean by  Data Mining ?

   It is basically a process of analyzing and processing a large amount of data

   that delivers a common solution.It allows organizations to take data driven

   decisions.It discovers relationships between data.

   data mining is basically used for fraud detection in data,finding correlation between

   data, analyzing website traffic etc   .

      Features of Data Mining:

       1. It is based on operational database

      2. It is used for analyzing data .

      3. It analyze  current data

      4. Identification of errors

     5. It is carried  out  by  expert engineers

 

   Process of Data Mining: 

                  1. Understanding of Business working

                  2.  Analyze data

                  3. Segregate Data

                  4. Model the data according to segregation

                  5. Evaluate the data

                  6. Use the data in specified work

 

      Technologies used in Data Mining: 

            1. Artificial  Intelligence

            2. Machine Learning  

            3. Natural Language Processing

            4. Cloud  Computing

            5. Decision Trees  

            6. Deep Learning(Neural Networks)

 

               

 

 

 

        

     

Cryptography and Steganography

    Cryptography and Steganography are two methods to secure your data in a network from 

    eavedroppers , hackers and  data theft .In this article we will see in details about the 

    two approaches.

       

      What is Cryptography ?

      Cryptography is a form of secret writing where the sender who sends the

      message to the receiver encrypts the plain text into cipher text   and send it

      when the receiver receives the message it again decrypts the cipher text into

      plain text.

      Cryptography plays an important  role in many factors to secure the data

      in an insecure channel  like privacy, confidentiality and authetication.

      Basically there are two types of Cryptography:

         1. Symmetric Key Cryptography

         2.Asymmetric Key Cryptography

 

  1. Symmetric Key Cryptography:

       This system is also known as private -key encryption or share key system

       or single key system.Here  private key is used by both the sender and reciever

       of information for encryption and decryption of the message.

      This system uses an algorithm commonly known as DES Algorithm.

      The major drawback of this system is that if the private key is exposed to the  

      the third party in any case the whole message will be public or stolen.

 

2. Asymmetric Key Cryptography:

    In this system of cryptography when a sender sends message to the receiver and 

    when the receiver receives the message  there are two keys used  differently by the

    sender and the receiver. This system uses and algorithm known as RSA Algorithm.

    The key used  for  encryption is stored public therefore it is called public key and

    the key for decryption is stored secret therefore it is called private key. 

   What do you mean by Steganography ?   

    Steganography means the hiding of information in a network in such a way as if

    there is no existence of Information. Here in this system the message is hidden by 

    a cover media using a certain type of algorithm.After the secret information is

    embedded into the cover  object the object is called as stego object which is being

    sent to the receiver. The receiver uses the same stego method for obtaining the

    original information

 

   Is there any advantage of  combining Steganography with Cryptography?

   Yes, Definetly it will be a powerful mechanism to  which enables people to 

    communicate with security. It enhances memory space, and strength for

    important information to send it across a open channel.

 

 

        

      

      

        

Virtual Private Network

 What is the meaning of Virtual Private Network ?

      It is a private  network which is used in a public network(internet)  via an

      encrypted tunnel to ensure your security and privacy of data,

      It is commonly  used  to  secure  your connection in the public  wi-fi  hotspot

      make your browsing private and hide your IP so that hackers do not

      steal your data.

   

    What is the need of Virtual Private Network ?

     Whenever you are working on the internet your whole browsing history ,

     IP address and all your personal data is being exposed that is why 

    Virtual Private Network is very important for securing your  data online.

 

    What are the benefits of Virtual Private Network ? 

      1. Hides your browsing history

      2. Hides your IP

      3. Hides your location

      4. Protects your web activity to maintain internet freedom

 

   How does Virtual Private Network works ?   

    Virtual Private Network basically creates a shield between your local network 

     and the computer   which may be located in another location which may be

     either in another country or in another state. 

     Irrespective of the place from where you are working your local network will

     make you seem that you are working from another place. This helps users

     to bypass their geographic locations, watch streaming media like Netflix,

     get protected  from Untrustworthy Wifi spot .

 

    How to Choose a good Virtual  Private Network  ?

    The market has n number  of  choices fro availing VPN services but there

   are certain benchmarks that should be seen to avail a good VPN which are 

   as follows:

     1. Location of the server

     2. Cost

     3 .Privacy  Policy

    4. Usages of Protocol

 

    In market  there  are  many  VPN providers . Some Providers give it free of 

    cost while some are paid but if your using data which is of high confidentiality

    you must use paid VPN  service which provide good security, unmatched data

    speed, proper usages of protocols.

  

   

      

      

 

Firewalls

 

     What is a Firewall ?

     A Firewall is a  system which continuosly  monitors  the traffic in a network for both

    incoming and outgoing .It tracks analyse and decide whether to allow  or  block 

     network  traffic  based on  certain rules and regulations.

     Firewalls guard traffic  at computer's entry  point  called ports where information

     is exchanged  within  external  ports.Firewall can be both hardware and software

     but if you are working in a network it is very much necessary to  guard your

     system by using both  types  of  firewall.

 

    Types of Firewalls:

      1. NGWF: Next Generation Firewalls 

       

 The Next Generation Firewall is a recent firewall technology which is used 

 to block modern day threats and attacks in network security.

 It includes Deep Packet Inspection which inspects the  data within

 the packet itself.

The NGFW is meant to serve many other security areas such as

 1. Blocking of apps which may pose threats to your device

 2. Informing about threats from a particular website or network

 

2.Statefull Multilayer Inspection Firewall :

 

This Firewall examine the packets and allow them to enter the network based on 

port , protocol and state. They examine packets to ensure that all the 

communication  that is taking place are coming  from  the trusted source.

 

3. Proxy Firewall :

 

 

Proxy Firewall act as an Intermediary between two end system. It serves as  

a gateway from one network to another for a specific application.It provides 

additional functionality  by  preventing  direct  connections  from  outside

the network.

4. Network Address Translation Firewalls:

 

Basically Network Address Translation Firewall is similar  to Proxy Firewall 

where it act as an Intermediary between group of computers and outside network.

Here in this type of Firewall a group of computers with different network 

address is connected to the internet with single IP address. In this way the 

attackers are mis-leaded by not letting them identify the IP address of

specific system thereby providing greater security against attacks .

 

 

 

 

 

          

   

Digital Signatures

 

 As we know with the rise of Digital revolution due to increase in cyber frauds we see

 that  Digital signatures have came up with massive usages duirng online shopping,

or online trading. here in this article we will get to know what do you mean by

digital signatures and how it works.

What is the meaning of Digital Signatures ?

As the name system  Digital signature is the type of signature that is done 

electrically using some mathematical pin or algorithm instead of using pen

or paper to ensure the authenticity of the message when it is being received

from sender to receiver. A Digital Signature is used to make sure that the

contents of the message have not been altered in the Transit.

It uses a standard accepted format called Public Key Infrastructure to provide

highest level of security.

How  Does  Digital  Signatures  Work ?

  Basically a digital Signatures works on the principle of Public Key Infrastructure

 according to which when a sender sends message to the receiver there are basically 

 two keys generated  one is public key and another is private key.

The Private key is with the sender which must be maintained properly by the sender

and The Public key is with receiver which he uses for decrypting the message.

Let us understand it with a example:

Step1: A wants to send a message to B

Step2:A must have the private key to sign the message digitally

Step3: An algorithm  known  as  hash value  encrypts the message into hash value

Step4: A's Private key encrypts the message using his private key and the 

            document is then said to be digitally  signed and sent to B

Step5: When B receives the Digitally signed document , B decrypts it using

              Alice public key which he received with the document.

Step6: After calculating the hash value is compared with the public key

Step7: if the decryption hash value generated is equal to the hash value 

            when he received the file  , that means the file is not tampered

            else if hash value do not  match , that  means  the file is  tampered