Discover Network

Monday 25 November 2013

WHAT IS NETWORKING

For best describing the answer of this question fist we have to learn what is network, its characteristic and how its is work.

WHAT IS NETWORK:- 

A Computer Network is a group of network that are connect together to communicate ans share resources such as files,printers and email, a network protocol control the network communication.
                             "A Network consists of two or more computers that are linked in order to share resources(such as printer and CD's), exchange and transfer files or allow electronic communication. The Computers on a network may be linked through cables, telephone lines, radio waves, satellite, or infrared light beams."
                                                                                                In actually network is like a way that we use for networking. if we want to doing networking we must have connected all computers in a manner to connect a specific network, is called networking.

NETWORK MODELS:-

(i)Centralized Network:

A type of Network where all users connect to a central server, which is the acting agent for all communication and the user account information. Most public instant messaging platforms use a centralized network also called a centralized server structure. Centralized network are also called. "hierarchical networks" and "host based networks".


(ii) Client-Server Network:

A Client-Server network is a network in which computer functionality is divided  in to two roles: Server computer, which provide services and control network operations and client computer.

(iii) Peer to Peer Network:

A peer to peer network, sometimes called a work-group, is a network in which resources sharing, processing and communications are completely decentralized. All clients and computers are equal in terms and permission.


NETWORK INTERFACE CARD  

A Network Interface Card or N.I.C. is an electronic device that provide a platform to a computer to connect to connect on the network. It is considered as a hardware part of Computer. 

Characteristic of N.I.C.

All network adapter have a globally unique physical address burned on to the card, its mean at the time of making card manufacture registered  it. The physical address uniquely identifies every individual card that connects to the network cable or media, that's why the physical address is also called the "MEDIA ACCESS CONTROL" , MAC address.

What is MAC

The MAC address is a unique value associated with a network adapter. MAC addresses are also known as hardware addresses or physical addresses. They uniquely identify an adapter on a LAN.
MAC addresses are 12-digit hexadecimal numbers (48 bits in length). By convention, MAC addresses are usually written in one of the following two formats:

                                          MM:MM:MM:SS:SS:SS


                                          MM-MM-MM-SS-SS-SS
The first half of a MAC address contains the ID number of the adapter manufacturer. These IDs are regulated by an Internet standards body. The second half of a MAC address represents the serial number assigned to the adapter by the manufacturer. In the example, 00:A0:C9:14:C8:29
   The prefix 00-00-0E indicates the manufacturer is Fujitsu Limited, Japan

Why MAC is must:

Recall that TCP/IP and other mainstream networking architectures generally adopt the OSI Model. In this model, network functionality is subdivided into layers. MAC addresses function at the data link layer (layer 2 in the OSI model). They allow computers to uniquely identify themselves on a network at this relatively low level.

Difference between MAC and IP:

Whereas MAC addressing works at the data link layer, IP addressing functions at the network layer (layer 3). It's a slight oversimplification, but one can think of IP addressing as supporting the software implementation and MAC addresses as supporting the hardware implementation of the network stack. The MAC address generally remains fixed and follows the network device, but the IP address changes as the network device moves from one network to another.

IP networks maintain a mapping between the IP address of a device and its MAC address. This mapping is known as the ARP cache or ARP table. ARP supports the logic for obtaining this mapping and keeping the cache up to date.

       Hardware Vendors and Registered MAC Address IDs 

Company                                                                                                                   Hex Address
Xerox Corporation, USA                                        00-00-00 – 00-00-09
Omron Tateisi Electronics Co., Japan                                                    00-00-0A
Matrix Corporation, USA                                                             00-00-0B
Cisco Systems, Inc., USA                                                                             00-00-0C
Fibronics LTD., Israel                                                                    00-00-0D
Fujitsu Limited, Japan                                                 00-00-0E
Next, Inc., USA                                                 00-00-0F
Sytek Inc., USA                                                 00-00-10
Normerel Systemes, France                                                 00-00-11
Information Technology Limited, United Kingdom                                                 00-00-12
Camex, USA                                                 00-00-13
Netronix, USA                                                 00-00-14
Datapoint Corporation, USA                                                 00-00-15
Du Pont Pixel Systems, United Kingdom                                                 00-00-16
Tekelec, USA                                                 00-00-17
Webster Computer Corporation, USA                                                 00-00-18
Applied Dynamics International, USA                                                 00-00-19
Advanced Micro Devices, USA                                                 00-00-1A
Novell Inc., USA                                                 00-00-1B
Bell Technologies, USA                                                 00-00-1C


Sunday 24 November 2013

1.1-WHAT PIECES ARE FOUND IN A COMPUTER?

(i) Adapter - Most of the time it refers to a card that plugs into the motherboard adding special capabilities not originally found on the computer.Other times it refers to tools to convert one connector type to another. 
(ii) Cables - A thick wire that connects the computer to the external device or power. 
(iii)Cache - An interface between the CPU and the memory (RAM and ROM). It helps the CPU keep running even though the RAM may be too slow.It does this by keeping a copy of what the processor has read/written. 
(iv)Card Slot - 

Saturday 23 November 2013

1. HARDWARE: “WHAT DO I NEED TO KNOW TO BUY A COMPUTER?”

What is a computer? I guess the easiest way I can explain it is as a little machine that follows very specific instructions over and over. A computer cannot learn and,unless told to do so, won’t respond to anything. Think of it as a very dumb dog that you have to teach to catch a ball every day and every time you want to play.

Computers do very complex math. Mind you, it is always related to the basics: add,subtract, multiply and divide. But as anyone who has had algebra and calculus will tell you: if you do enough of these basics, you can get approximations of more sophisticated math that are pretty close to reality. Computers do this math very quickly. Often these calculations are done in millions per second. Imagine multiplying 10 million pairs of multi-digit numbers per second. I have a hard enough time myself doing a 3-digit multiplication in less than a minute.
  
Computers can store a vast amount of information and retrieve it at extraordinary speeds.When everything works correctly, this data is as fresh and unblemished by time as when it was first stored. It can record information about everything (given it has sufficient
storage capacity). While this may not seem to be a great achievement, think about this:when you last went to the store, how much did you pay for each item you bought? Computers can store this kind of information a lot better than we can recall it. Also, one

of those DVD-ROMs that we see so frequently can store the entire Encyclopedia Britannica along with photos.(Please note that if you buy their DVD-ROM set, it has more than just text and photos. So, the set has several DVD-ROMs.)


What have computers done for us? Consider the following: 
1. Made the world incredibly smaller by facilitating communications.
2. Advanced science and medical discovery more in 10 years than in centuries of history.
3. Designed cars, roads, cities, clothing, etc.
4. Tested transportation long before the prototypes ever left their studios.
5. Exploded our imaginations with color and virtual reality.
6. Controlled our market-place and caused the “Black Monday” crash.
7. Opened freedom of speech to areas all over the world via the Internet.


The list goes on and on. The computer has done a lot to shape the modern world—some good and some bad. In all, it has been a great blessing when properly used. What can computers do for you? Well, hopefully, this text will show you.