Basic Concept of Database


Data: Data is sequence of digit. It is raw materials of information.
System: Some related things make a system. System is divided three steps.
(1)               Input
(2)               Processing
(3)               Output
Data Dictionary: Data Dictionary is a file which content the primary description of information of data file data under database.
Data Structure: The process of arranging databy many way is called data structure.
The flowing are data structure
(1)               Array
(2)               Record
(3)               Stack
(4)               Queue
(5)               Tree
(6)               Linked List
Array: Array means class Arranging same kinds of data is called Array. There are three kinds of array
  1. One Dimensional Array
  2. Two Dimensional Array
  3. Three Dimensional Array
Record: The collection of some field is called record.
Stack: Stack is one kinds of data structure where LIFO (Last in First Out) process is flowed.
Queue: Queue mean line or row. In this structure Last kept data use first. This system is Called FIFO
Tree: In this structure data are input hierarchically.
Pointer: Pointer is an indicator in data structure pointer use to speed up the computer.
String: Combination of some ward is string such as Karim, Rahim, Masud, Dhaka etc.
String Variable: If Variable will be ward is Called String. Normally First character of field name is string which express by first character with $ Sign
Entity: Each record in he data file of database is called entity.
Attribute: Each field in record of data file of database is called Attribute.
4GL: Forth Generation Language. The Database management language is called Forth Generation Language.
  • Characteristics of RDMS
  1. We can find the information by different condition
  2. We can create customize form to input data
Data Schema: The over all Design of database is called database Schema.
Database Schema: Data management system has special language which is called database language.
There are two kinds of database language.
  1. Procedural language
  2. Non – procedural language
DML: The language of DBMS by which data can be manipulated in the Database.
DDL: By this language describe data schema definitely by expressing a expressing a set of definition.
Procedural DML: In this language system the user define data will be store what kind of database and how can retrieve that data.
Non – Procedural Language: In this Language system the user only define data will be store what types of database but no need to define how data will be retrieve.

Topology



The logical and physical collection of computer in a network is called  topology .Topology means now a days physical topology .
Classifications are :
a.      Bus topology
b.      Ring  topology
c.       Star topology
d.      Tree topology
e.       Mesh topology
f.        Hybridge topology
Bus
In a bus topology all computers are connected to a central cable called bus or backbone.
Star
A star topology is intended with each node (file server, workstations, and peripherals) connected straightforwardly to a central network Devices. Data on a star network passes through the network Devices before continuing to its destination. The network Devices manages and controls all functions of the network. It also acts as a repeater for the data flow. This configuration is common with twisted pair cable. Though, it can also be used with coaxial cable or fiber optic cable
Ring
A ring topology may show to be the same as a star topology. on the inside, the MAU (multistation access unit) of a ring contains wiring that allows information to pass from one device to another in a circle or ring . The Token Ring protocol uses a ring topology.
 Tree                                                     
A tree topology is the combination of characteristics of linear bus and star topologies. It consists of groups of star-configured workstations linked to a linear bus backbone cable. Tree topologies permit for the extension of an existing network, and enable  to configure a network to meet their needs.

Important definition for MCSA

multiple master replication : a technique usually associated with directory service, in which identical copies of database are maintained on various computer throughout the network.

MAU ( Multistation Access Unit) : a hub used in token ring network. this is more complicated than ethernet hub.  because instead of repeating incoming signals out through all port simultaneously, mau sends incoming signal through each port in trun.

 multitasking : A technique by which a computer with one processor executes multiple tasks simultaneously.      

  network access control : A hardware device used on wireless LANs employing the infrastructure topology to provide an interface between a cabled network and wireless network.

Modem : it is a network device which is need for modulation and demodulation. it make analog signal to digital and digital signal to analog signal.

 Port : A code number identifying the process running on a TCP/IP computer.  transport layer protocol such as TCP and UDP specify The port number of the source and destination application processes in the header o
f each massage they create.

       PROTOCOL: An ASCII Text file found TCP/IP systems that lists the codes used in teh Protocol field on the Internet Protocol(IP) header.

 Proxy server:  Proxy server is a server by which unregistered IP can access to the internet. The proxy server must has a registered IP,

redirector :  A network client component that determines whether a resource requested by an application is located on the network or on the network.

Remote Bridge: A network device operating on data link layer of the OSI reference model  which is connect to Lan at different location with a WAN link. 

 Repeater : repeater is a network device which amplifies network signal enabling them to travel longer distance without suffering for effect of attenuation.

routing table: 

schema : schema is the structure of directory service . such as Active directory in Microsoft Domain Controller, NDS in Novel Network.

services :  services is a windows term to do  special task, such (DNS) Donain name service is for name resolving. spooler is for print share etc.

SERVICES : a ASCII test file which contain the codes used  in the source port and destination port fields of the TCP and UDP header.

Small computer system interface (SCSI) : a Peripheral Device Interface which enable you to connect internal and extarnal device to a computer.

Some Important Definition for Network engineer

Directory service: A database containing about network entities and resource. Such as active directory for windows 2000 server, bindery for novel Net Ware.

Domain :Domain is a groups of workstation and other devices on a network that are administrated as a single unit.

Domain controller: A computer configured by  windows 2000/2003/2007 that is designated to store and manage directory services information.\

Domain Name service: an service which map IP address to Domain name.

 Driver :  a software by which operation system communicate with hardware.

DHCP : Dynamic Host configuration Protocol is a service which provide IP address to the network automatically.

Dynamic Routing : by this routing systems router builds  a routing table automatically by specialized protocol.    

EIA/TIA: Electrical Industry Association/ Telecommunication Industry Association

FDDI : Fiber Distributed Data interface

fiber Optic: a network cable use a technology that uses light to send signal  rather than electrical charge use by copper cables.

FTP : File Transfer protocol, work application layer on OSI systems

Full Duplex: a form of network communication in which to connected systems can send signals at a time such telephone line.

Half Duplex: a form of network communication in which to connected systems can send signals in one direction at a time such as radio

Hops : In an internetwork each router is a hop.

hosts : An ASCII text file which is used by TCP/IP computer to resolve host name to IP address.

Hub : Hub is a network device which is used in star network  topology to connect the computer with each other.

 IPCONFIG : a command line utility to know the ip configuration of a computer.

 incremental Backup :  incremental Backup systems is a  backup systems by which we can backs up which was modified or created after the last incremental or full backup. this systems sets archives bit.

IEEE : International Electrical and Electronic  Engineers: A organization formed on 1984 which is dedicated to development and publication of standard for the computer and electronics industries

Necessary information for network Specialist

Active directory: active directory is a directory in widows 2000 server where all data and information are stored of a domain controller 

 ARP: address resolution protocol which is use to resolve IP Address into the hardware or MAC address. It is a data link layer protocol.


ad hoc topology : it is a wireless technology . Where a group of computers are all equipped with wireless network adapter and are communicate with  each other freely.

infrastructure topology : in an infrastructure topology’s networks consist wireless equipped computer that communicate with wireless transceiver connected to the lAN by standard cables. Those transceiver is call access point.


ADSL :  asymmetrical digital subscriber line. a point to point digital WAN technology that use standard telephone line  

ADSL Terminator Unit – R : It is a device located at the client end ADSL connection. also called a DSL transceiver.


AUI : asynchronous Unit interface


 Backbone : a medium by which a series of networks connected. \

baseband network:  a network  that use a medium that can carry only one signal at a time

Broad brand : a network that use a medium that can carry multiple signal at a time.

bindery : the server based flat file directory service used in novel net Ware service.

BMP: A file format commonly


 BNC: Bayonat Neil Concelman. a kinds of connector used thin Ethernet networks

 Bridge: a network device which works at data link layer. which reduce network traffic.

Broadcast:  a massage transmitted to all of the other computer on the local network.  

Broadcast domain: a collection of network that receive a broadcast massage transmitted by any one computer.

Bus: Ethernet topology in which each device is connected with next device.

 CATV ( cable television network: 

CSMA/CD : Carrier sense Multiple Access with collision detection

CSU/DSU: channel service unit/ data service unit

Protocol information

  1. Protocol is the language of computer by which the computer communicate with each others over the network. computer use different protocol  such PPP, SMTP, SNMP, UDP, TCP/IP.etc.
  2. IANA: Internet Assigned Numbers Authority: this Organization is responsible for providing real IP in the world.   
  3.  
  4. HTTP : Hyper Text transfer Protocol : an application layer protocol that is basis for world wide web communication

  1. ICMP : Internet control massage protocol : A network layer TCP/IP protocol that carries administrative massage, particularly error massage and information queries.


  1. IMAP : Internet Mail Access Protocol.: An application layer TCP/IP protocol  used by mail clients to download the mail from a server.

  1. ISDN : Integrated Services Digital Network: A dial Up communication services that uses standard  telephone lines to provide high speed digital network.

  1. IP : Internet Protocol : this is a connectionless protocol which work in network layer in OSI Model. IP Packages the data as a datagram. just like the envelope of a letter.


  1. IPSec : IP security Protocol. is a set of protocols which is designed to serve encrypted communication on network layer. it is a TCP/IPprotocol.
  2. IPv6 : latest version of internet protocol that expand  IP address 128 bits instead of 32 bits.

  1. L2TP:  layer 2 tunneling protocol: A Protocol used to established virtual Private network connection across the internet,

  1. NAT: Network Address Translation is a firewall which enables TCP/IP client computers using unregistered IP address to access internet. 

  1. NNTP : Network News Transfer Protocol is a  TCP/IP Protocol to used to post, distributes and retrieve Usenet massages to and from news server

  1. NTP : Network Time Protocol is a TCP/IP protocol to synchronize the clocks on network computer.


  1.  Point to point Protocol (PPP) : it is a Protocol of datalink layer to connect remote computer specially for dial Up connection.

  1. PPPoE : Point to point protocol over ethernet is  A TCP/IP protocol that defines a mechanism  for established different negotiated PPP connection between workstation on a network and provide services on the other network which  access through a DSL connection or CATV

  1. PPTP : Point to point tunneling protocol is a protocol which work in datalink layer to make secured communication for VPN (Virtual Private Network.).


  1. NetBEUI ( NetBIOS Extended user interface) :  Connection oriented protocol suitable of small network. It is not routable protocol.

  1. New Technology File System (NTFS): The latest File system of windows platform. Which has local security and domain security.


  1. Network News Transfer Protocol (NNTP) : A TCP/IP  Protocol to used to post, distributes and retrieve Usenet massages to and from news server

  1.   Open Shortest Path First (OSPF) : A Dynamic Routing system. where routing table is automatically upgraded and it calculated shortest path to sent data.

How to configure DHCP and DNS server in windows 2000 server

DHCP




1.              Start > program> administrative tools> DHCP
2.              Right click on the server , select the New scope on the pop up manu.
3.              Wizard will start, click next.
4.              Type name of scope and type comments to about the scope >next
5.                Input the range of IP address> next
6.              Input the exclude IP address which I need to reserve for statically assign. Next
7.              Provide the lease duration
8.              Router (default gateway of the network. Next
9.              Assign DNS server IP
10.        Assign WINS server IP
11.        Active the DHCP server
12.        Finish
13.        Authorize the DHCP Scope by right click DHCP server window

 

DNS server

Requirement

1.                Start > program> administrative tools> DNS
2.                If not found DNS in the administrative tools please install     
         that by  the following way
                                                                                                                                     i.      Start> control panel> add remove component > select network service , click details> check DNS > ok . enter CD Rom in the CD Drive
3.          DNS server window will appears right click your DNS server and select configure from the pop up menu.
4.                DNS wizard will appears, click next
5.                If new DNS select this is the first DNS, otherwise check 
         bellow option.
6.                Yes create a forward lookup zone, next
7.                Select new zone, if you configure on domain controller you
         Must select active directory integrated zone. Standard  
         Primary DNS is the copy of master DNS. Standard secondary    
         DNS is for redundancy and load balancing. Next
8.     Next
9.     Reverse look up zone dialog box appears select yes and click 
        Next
10.   Finish.

OSI Reference Model



OSI (Open system inter connection) Reference Model:



The following are OSI reference model

  1. Application layer
  2. Presentation layer
  3. Session layer
  4. Transport layer
  5. Network layer
  6. Data Link layer
  7. Physical Layer
 

Application Layer: the top layer of OSI reference model. the HTTP, FTP,SMTP, DHCP, SNMP protocols are work in this layer.

Presentation layer: this is 2nd  layer of OSI reference model.this layer's  responsibility is translating the Syntaxes used by different types of application in different computer in the network. in this layer a computer translate the data accumulated  by its own applications from its own abstract syntax to a common syntax which is suitable to transmit  through the network.

Session layer: the most important task of this layer are dialog control and dialog separation. dialog control is exchange information between two systems on the network. This layer Establishe, manages as well as  terminates sessions between applications


Transport Layer: The TCP & UDP protocol works in this layer. This layer provides   end-to-end connection between processes.

Network layer: in this layer the is responsible for packaging transport layer data in diagrams, addressing them to its final destination, routing them across the internet-work and fragmenting the diagrams as needed. the internet protocol (IP) work in this layer. This layer translate between different network types

Data link layer: This layer is responsible for network layer packaging network layer data ,addressing to its next destination. the PPP, SLIP works in this layer.

Physical Layer: The bottom layer of OSI reference model. This layer define what kinds of medium will be in the network

Types of Networking


There are three basic types of networks include:
  1. LAN: Local area network
  2. MAN: Metropolitan  Area Network
  3. WAN: Wide Area Network

Local Area Network

A Local Area Network (LAN) is a network where computer are connected with each other relatively small area. It is usually limited to a geographic area such as a  lab, school, or building. LAN computers can be not more than a mile apart.
LAN consists of the following components:
  •  Computers
  •  Network interface cards
  •  Peripheral devices
  •  Networking media
  •  Network devices
LANs are designed to:                      
  Operate within limited Geographic Area.                                                                                                                                                                                    
  • Allow multi access to high band with media.
  • Control the network privately under the local  administration
  • Provide full time connectivity to local services
  • Connect physically adjacent devices.

Some common LAN technology include the following:

  Ethernet: In  LAN configuration, one computer is for the file server. In the file server all software is stores that controls the network and  the software which can be shared by the all computers which is attached to the network. All Computers which are connected to the file server are named workstation. The workstations may be less configuration than the file server. LANs, can be setup by all kinds Topology.

Network Topology


Topology

The logical and  physical arrangement of computer in a network is called  topology .Topology means now a days physical topology .
Classifications are :
1.      Logical
2.      Logical bus
3.      Logical Ring
4.      Physical
5.      Linear Bus topology
6.      Ring  topology
7       Star topology
8      Tree topology
9       Mesh topology
10    Hybrid topology


Bus
In a bus topology all computers are connected to a central cable called bus or backbone

Star
 Star topology is a topology where each computer is connected with  central network hub or concentrator. Data passes through the hub or switch before fix up destination on a star topology. All functions are manages and controls by the hub or switch of the network. this hub or switch also acts as a repeater for the data flow. usually this network is configured by twisted fair cable. moreover we can use coaxial cabel or fiver optic cable in this kinds of network. Star topology is using in maximum Local Area network
Ring

A ring topology is looking like a star topology. we use multistation access unit called MAU instead of switch/hub of a ring contains wiring that allows information to pass like circle or ring.from one device to another Token Ring protocol uses in  ring topology.

Computer Networking


Computer Networking : 
A Network consists two or more   computers that are connected by using 
Various media in   order to share resources such as
1. Printers
2. Scanners
3. Hard disks
4. CD-ROM
5. Plotters
6. Floppy disks

Exchange files, or allow electronic communications. The computers on a network
May be linked   through cables, telephone lines, radio waves, satellites ,  or infrared light beams.   In summary   all networks must have the following: [1]:
i) Something to share (data)
ii) A physical pathway (transmission media)
iii) Rules of communication (Protocol)

The goal of computer networking are to provide services and to reduce equipment costs . Networks Enable computers to share their resource by offering services to other computers. Some of the reasons for networking pc s are as follows:
Share files
Share printers and other devices
Enable common administration and security Supporting network applications such as electric mail and data base service. 

 This section provides information on the following components:
  • File Servers
  • Workstations
  • Network Interface Cards
  • Switches
  • Repeaters
  • Bridges
  • Routers

Modern Technology

The main role of Modern Technology and Science is escalating and has key impact on daily lives. Advancements in Science and Technology are heartwarming people all around the world. Modern Technology help human lives by improving medicines sector and provides better treatment for diseases. It develops transportation by helping us by moving from one corner to another of the world in hours.



The  modern technology make a revolutionary change on human being  . it  has changed our lives and helped the economy grow.  live hood is very easy by the help modern technology, Modern technology give us digital life. Computer is the gift of modern technology. It change out civilization. Now a days every things is the computerized.  We can not think anything except this machine. By it we can connect to the internet. and by internet we can do Business, Medical services; study , internet marketing etc.
Modern Technology improve lifestyle by developing the following sector
  1. Medical
  2. Agriculture
  3. Communication
  4. Education
  5. Business
  6. Atomic Power

Modern technology has produced a lot of new problems. Most of these problems come changes of environment because of Modern technology.



The mechanized of electronics parts uses thousands of poisonous chemicals. These chemicals have polluted water near electronics factories. Many workers become sick after being around these materials.
Electronic products also create a huge problem of poisonous waste. Most of the people throw away their used Electronic product after out of work. Those are very harmful for environment.
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