PROTOCOLS

PROTOCOLS:

A protocol is a group of rules that govern's data communication and networks. It represents the agreement between the communicating devices sender or receiver. Two devices may be connected but not communicated; just a person speaking French cannot be a understood by a person who speak only Japanese.

GENERALL DESCRIBTION OF DATA COMMUNICATION

GENERALL DESCRIBTION OF DATA COMMUNICATION:-
1) Simplex.
2) Half Duplex.
3) Full Duplex.

SIMPLEX:-
One way transmission of data is called Simplex. In Simplex transmission signals are transmitted in one way direction one station is transmitter and other is Receiver.

   
HALF DUPLEX:-
In half duplex operation both station may transmit, but only one at a time.

     

FULL DUPLEX:-
In full duplex operation both station may transmitted simultaneously. The medium is carrying signals at both directions at same time.

Data communication can be described simply in 3 terms.
1) Data Transmitter. (Source)
2) Data Transmission. (Channel)
3) Data Receiver. (Receiver)

MEDIUM

MEDIUM:-

The physical path of two devices between sender to Receiver is known as MEDIUM.

Example:-
Twisted pair wire, coaxial cable, fibber optic cable, radio waves and etc.  

History Of Computer

History Of Computer

It is well known that computers have changed the way of life. The computer has transformed the way we communicate and learn due to business . Restart the computer control have replaced the backup task performed by humans.
The information revolution is to be found infected in every way to his own life . Today all computers in machine control .
Example: -
Train , plane, etc Automobiles

Computer Generation:

First Generation - (1945-1955)
• The computers, ENIAC , EDVAC , UNIVAC and Mark 1 covers the initial phase of development of computers belonging to the first generation of computers.
• This equipment is mainly made ​​"between" 1945-1955 .
• The computers developed in this generation used vacuum tubes.
• devices These devices were faster calculation time . However, the memory size of these computers was limited.
• They were big , expensive and unreliable.

Second Generation - (1955-1964)
• The transistor replaced vacuum tubes and leads to the second generation of computers like UNIVAC 2 IBM 1401 and CDC 1604.
• These computers were smaller, faster and more reliable compared to first generation computers .

Third generation: - (1964-1970)
• In early 1960, solid-state electronic technology has been introduced .
• The development of integrated circuits ( ICs).
• On Deck technology as solid state .
• generation equipment is more reliable , faster and smaller than the previous once .

Forth Generation - (1964 -Present )
• In 1971 , the development of integrated circuit technology was sufficient to incorporate all the major functions of a computer on a single chip called " microprocessor " .
• The introduction of the microprocessor is the next generation computer age .
• A direct consequence is the development of a microprocessor or microcomputer that brought down the organization personally.

Fifth Generation - (now - beyond)
• Defining the fifth generation of computers is a bit difficult because the field is in its infancy .
• The most famous example of a fifth generation computer is the fictional HAL900 of the novel by Arthur C. Clarke, 2001 : A Space Odyssey .
• The invention of Artificial Intelligence of the fifth generation.
• The example of the fifth generation computer is Pentium 4 dual core laptop supercomputers , personal computers, handheld computers , mainframes and more.
• Today, computers have attributes of fifth generation computers . The best example is a.i reborts .

Component of E-Commerce

Component of E-Commerce

. The main components of E -Commerce are given below.
1.Web browser .
2.Web Server .
3.System Manager / payment transaction.
4.Standards (Exit and emerging ) .

Web browser.
1.A software that allows people to access the World Wide Web ( WWW) .
2.Internet Explorer and Netscape Navigator are the two most popular browsers.

Web server.
Web server are special computers that store and deliver Internet ( use ) of Web pages.
A Web page is a specially formatted document that you can view in your browser.
A Web server can host one or more websites.

System Manager / payment transaction.
Exchange of electronic memory, including through (mostly) checks, smart cards, digital cash , and electronic funds transfer ( EFT ) .

Standards (Exit and emerging ) .
Methods to facilitate interaction e -Commerce , is to ensure the security of transactions , reliability, Electronic Data Interchange and privacy

E - COMMERCE

E - COMMERCE

1. E - commerce stands for Electronic Commerce .
2. E - Commerce is a kind of industry where the building and sale of product or service is performed on the electronic system such as the Internet and other computer networks .
3.E - Commerce is generally regarded as the marketing aspect of E -Business . It also involves the exchange of data to facilitate the financing and payment aspects of the business transaction.
Types of E -Commerce
There are 5 main types of e -commerce .
1.Business consumption (BTC) .
2.Business to Business . (B2B) .
3.Consumer for consumers ( C2C) .
4.Peer to Peer ( P2P) .
5.Mobile Commerce (M -Commerce ) .

Business to Business . (B2B) .
This is the greatest form of e -commerce businesses involving billions of dollars.
In this form the buyer and sellers are both business entities and business entities and do not have one in the divisible computers.

Business to Consumer ( B2C) .
The basic concept behind this type is that online retailers and marketers can sell their consumer products online using clear data that are available through various online marketing tools .

Consumer to Consumer (C2C) .
It center online transaction of goods or services between two people. With no intermediary involved are visible , but the parties can not perform operations without the platform that is provided by the market maker such as eBay .

Peer To Peer ( P2P) .
Due to it is a model E - commerce but it is more than that. It is a technology in itself that helps people to directly share computer files and computer resources without having to go through a central web server.
Mobile commerce (m - commerce) .
It refers to the use of mobile devices to perform transactions . Holders phones can design and development companies optimize websites to be viewed correctly on mobile devices

FUNDAMENTAL CHARACTERISTICS OF DATA COMMUNICATION

FUNDAMENTAL CHARACTERISTICS NETWORKING:-
The effectiveness of a data communication system depends on three basic characteristics.

1) Delivery
2) Accuracy
3) Timeline

DELIVERY: -
The system must supplied data to the correct destination.

CLARIFICATION: -
The system must provide the data accurately. The data that has changed in the transmission and are uncorrected are unusable.

TIME LINE:-
The system must delivered timely data. The transmitted data is unnecessary delay. For example in the case of video and audio delivered in due time delivering average data as they are produced. In the same order in which they are produced with significantly behind. This type of service is called real-time transmission.

HYPERLINK

HYPERLINK

• In computer or computing a hyperlink (or link) is a reference to data that the reader can directly follow, or that is followed automatically.

• A hyperlink points to a whole documents or to a specific element within a document.

• Hyperlink is text with hyperlinks. A software system for viewing and creating hypertext is a hypertext system, and to create a hyperlink is to hypertext (or simply to link).

WEB BROWSER

WEB BROWSER

• A web browser (commonly referred to as a browser) is a software application for retrieving, presented and traveling information resources on the world wide web (www).
• An information resources is identify by a uniform resource identifier (URI/URL) and may be a web page, image, video or other piece of contact.

There are some famous browsers are given below:

1. Google Chrome Browser. (https://www.google.com/intl/en/chrome/browser/)
2. Mozilla FireFox Browser. (http://www.mozilla.org/en-US/firefox/new/?f=26&utm_expid=71153379-28.fvIED7HGROyjOifCfo3hhQ.1&utm_referrer=https%3A%2F%2Fwww.google.com%2F).
3. Opera Browser. ( http://www.opera.com/computer)
4. Safari Browser. (http://www.apple.com/safari/) 

The ISO ( International Standards Organization )

The OSI (Open Systems Interconnection) 

The ISO ( International Standards Organization ) decided to build a framework of standards that different providers can use to communicate over a network equipment and applications . This framework is now considered the standard for communication networks . The OSI has seven layers , which divides the task working groups easier to manage smaller . Each task or group of tasks assigned to each layer can be implemented independently. This limits the complications between the layers because the solutions offered by one layer does not affect the other layers.

The layers 7 may be logically divided into two subgroups . Layers 7-4 focus on end to end communication of data sources and destinations. Layers 3-1 are to provide constant communication between network devices. An easier way to watch the OSI model divides the upper layers (7 , 6, 5 ) lower layers (4, 3, 2, 1). The upper layers deal with issues of application and implementation in the software. The highest layer , the application layer , is closest to the end user. The lower layers are responsible for data transport . The physical layer and data link layer are implemented in hardware and software. The lowest layer , the physical layer , is closest to the physical network medium ( the son , etc.) and is responsible for placing data on the carrier .

The following is an explanation of top-down of the OSI model . It starts with the PC of the user and follows what happens in the user file during his visit that the different layers of the OSI model . The top-down approach was chosen specifically ( cons from the physical layer and work up to the application layer ) to facilitate understanding. It is used here to show how the user files are processed ( through the layers ) in a bit stream for transmission over the network .

LAYER 7 - APPLICATION

The application level provides services that directly support user applications , such as user interface, e -mail , file transfer , access database , etc. There are many protocols that layer are generally required such as HTTP, Web , FTP, TELNET , SMTP . It gives applications access to the network through the layers below. Another important function is to transfer files between computers. Some filenames computers store or represent lines of text differently. The application layer supports incompatibilities and allows a smooth transfer between systems.
Protocols: FTP1 , HTTP2 , SMTP3 , DNS4 , TFTP5 , NFS6 , TELNET7 .


LAYER 6 - PRESENTATION

The level of presentation is a translator between the application and the size of the network. Unlike lower layers , its concern is the syntax and semantics of the information transmitted . Most users do not exchange programs random strings of binary bits . They exchange data such as names , addresses , dates, etc. Different computers store data in a different way . In order to allow these computers to transmit data to the other of the presentation layer translates the data into a standard form to be used on the network. Another function is that the data compression can be used to reduce the number of bits required to transmit the information packet . Security is also added to this layer by using the data encryption and decryption . This prevents others from intercepting the data and be able to decipher the meaning of the bits.
Protocols: ASCII8 , EBCDIC9 , MIDI10 , MPEG11 , JPEG12 .


LAYER 5 - SESSION

This layer allows applications to link systems communicate using a session. It opens and closes using the communication link . It also acts as a control mechanism which controls the dialogue is able to transmit . Sessions can allow data to be sent in both directions at the same time or one direction. The session layer determines that the transfer capacity currently . Another possibility is useful for inserting control points during data transfers. For a large file transmission if the system crashes checkpoints allow the system to start downloading the last known point of control. An example of this is an interactive connection or a file transfer , the session would recognize the names in the session and save them in a story. It could then connect and reconnect in case of a system crash or two systems.
Protocols: SQL13 , RPC14 .


LAYER 4 - TRANSPORT

The basic function of the transport layer is to accept data from the session layer , breaking the data into smaller units , if necessary, and send data packets to manage the network layer. At the destination this layer is responsible for combining the packets in their original condition . This layer also checks if the layers are in good order upon receipt and not as duplicated. If an error occurs in one of the packages there is a request for retransmission of the packet . There are two protocols that are sitting at this layer. First, TCP connects the transmitter and receiver using a socket which is determined by the IP address and port number. TCP keeps track of the packet delivery order and which ones should be returned. UDP on the other hand is a connectionless communication and does not guarantee delivery of packets between the transmitter and the receiver . Because it has no connection to the sender sends the data to the network with an IP address of the receiver and hope it goes to its destination. As there is no means to ask the sender to retransmit due to an error there is little protection error if any .
Protocols: TCP15 or UDP16 .



LAYER 3 - NETWORK

The network layer handles essentially all questions address . This layer handles the packets determines the best path or route , and manage network problems such as congestion data . There are three ways in which packets are routed to their destinations. First, there could be a static route through the entire network that will never change. Second, there may be a static line is used only during a particular session between the sender and the receiver . Finally, the packets can be sent dynamically through the network using changing paths to avoid bottlenecks . Bottlenecks are formed when there are too many packages in a subnet having them interfere with each other . The network level is responsible for the conversion of the network address and names to the MAC addresses of the machines . One of the most important functions of this layer is to allow the possibility of two different networks using addressing schemes in conflict to be able to send data to each other. The network layer allows different protocols to "talk" to each other and understand where the packet's destination is . Routers operate at this level by sending packets along the network .
Protocols: IP17 , ICMP18 , ARP19 , PING20 , Traceroute21 .



LEVEL 2 - DATA LINK

The data link layer defines the data format on the network. All data sent across the network are made in a part which is made at this level . The setting is a uniform way of sending data and the address and error control capabilities information. CRC is used for error detection at this level . If the receiving end of the CRC fails at this level, it is a request to the sender for retransmission of the packet .
Protocols: IEEE 802.222 , 802.323 , 802.524 .


LAYER 1 - PHYSICS

The physical layer is responsible for the establishment, maintenance and end physical connections ( point to point) between computers. This layer is concerned with the actual interpretation of the bit stream into an electrical signal that can be transported across a physical medium . The protocols of this layer according binary transmission , voltage levels , and data rates . This layer would also specify the physical medium properties such as cables and network adapters .
Protocols: IEEE 802.323 , 802.524 The ISO (International Standards Organization) Decided to build a framework of standards That different providers can use to Communicate over a network equipment and applications. This framework is now Considered the standard for communication networks . The OSI layers Has Seven , All which Divides the task working groups Easier to manage smaller . Each task or group of tasks Assigned To Each layer can be Implemented Independently . This limits the complications Between the layers Because the solutions offert by one layer Does not affect the other layers.

The layers 7 May be Logically divided into two Subgroups . Layers 7-4 focus on end -to-end communication of data sources and destinations. Layers 3-1 are to Provide constant communication Between network devices. An Easier way to watch the OSI model Divides the upper layers (7 , 6, 5 ) lower layers (4, 3, 2, 1). The upper layers deal with issues of enforcement and implementation in the software . The Highest layer , the application layer , is closest to the end user . The lower layers are responsible for data transport. The physical layer and data link layer are Implemented in hardware and software . The Lowest layer , the physical layer , is closest to the physical network medium (the sound, etc. . ) And is responsible for Placing data on the carrier .

The Following is an explanation of top-down of the OSI model . It starts with the PC of the user and follows what happens in the user file falling on His Visit That The different layers of the OSI model . The top-down approach Chosen WAS SPECIFICALLY (cons from the physical layer and work up to the application layer ) to Facilitate understanding. It is used here to show how the user files are processed ( through the layers) in a bit stream for transmission over the network .

DATA COMMUNICATIONS

DATA COMMUNICATION

The medium term telecommunication communication clustering distance. The word data refers to the information presented in any form agreed by the Parties Creation and use of data. Data communications are exchanging data between two devices through a certain form of the transmission medium: as a wire rope.
The topics in this section:

1. The parts of a data communication system
2. Data Flow

• The Parts of a Data Communication System:

x

• Data Flow:

System Memory

System Memory

ROM ( Read Only Memory)

RAM stands for Read Only Memory , ROM is memory All which data is prerecorded computer has-beens . Code and / or data programming on a chip ROM is written to the chip factory. It can be read , it can not be objective deleted or removed . It is permanent. Retains data or ROM icts happy, Even When the computer is off , unlike the main computer memory (RAM) , Which Requires a constant electrical load to keep His information. For this reason , the ROM is Considered " non- volatile" RAM and "volatile" .

ROM chips are used in all kinds of electronics calculators to video games. Most personal computers -have several applications of ROM . These chips Often store information and programs do not need That to be changed Permanently and criticism , or do not need to be written . Most computers -have a small Amount of the code ROM That blinds That starts the computer boots . The first computers used to store aussi the BIOS ROM (O base system) That acts like a translator Between the hardware of the computer and operating system .

The problem with using ROM BIOS chips thesis information Is That computer manufacturers HAD to build systems around Their ROMs made ​​available and Their coding. Because the information WAS written to the chip falling on the manufacturing process , to exchange the chip Involve the development of new assembly lines and the purchase of new equipment. Would it cost a small fortune if a computer or motherboard manufacturer only HAVING HAD visions of the coding of modified thesis has to adapt to new or improvements Developments They May wish to Incorporate into Their products chips.



PROM (Programmable Read Only Memory)

Remember , Everything that a computer can Understand is 1 and 0 . Here's how a transistor works . It Allows electricity to pass or not . There is an electric load , or it is not . Is on or off (1 or 0) . These memory chips are made ​​up of millions of tiny transistors All which -have the 0 or 1 . Just like millions of tiny switches or fuses .

With a ROM chip , thesis Permanently switches are set at the factory in Their respective countries or off (1 or 0) positions. In the case of a PROM (Programmable Read Only Memory) chip is Manufactured with all breakers or fuses icts little intact , or set to '1 ' ( empty memory) . When chips are programmed thesis with the use of a device called Expired PROM is programmed ( or burner ) , a high voltage pulse destroys selected electronic switches, burning in the parameters must be That change to a '0 '.

So PROM is programmable goal only once . As ROM , it is permanent or nonvolatile . It can not be erased .
EPROM ( Erasable Programmable Read Only Memory)

An EPROM is a special kind of PROM That can be reprogrammed . The information is Stored as electric loads Deposited on the chip (1 and 0) . EPROM are easy to spot on the motherboard of your computer . They are always in the form of a DIP chip as ROM and PROM , They Will goal -have a metal tag as on top of the chip (usually showing the serial number , version, date and name of the manufacturer) . It is for good reason . The label covers a small window .

An EPROM can be erased by Removing the circuit and the projection of ultraviolet light through the window above chip . Then it can be reprogrammed by an EPROM burner moyen de . EPROM are still Considered non - volatile , They Will not lose Their information When the computer is off .





EEPROM ( Erasable Programmable Read Only Memory Electronics)

EEPROM Does not Have To Be removed and feel to the manufacturer to be reprogrammed . It can be reprogrammed while you electronically in the system by using a software designed SPECIFICALLY for That purpose . Also , EPROM must be erased completely Call , Then reprogrammed . With a single byte EEPROM can be erased and rewritten . In fact , the EEPROM is erased and written one byte at a time , Which Makes it slow as memory goes. Yet , it Allows manufacturers the possibility of configuration parameters on the chip EEPROM of an expansion card . Using the Software Provided with a device , DMA channels , IRQ and I / O addresses can be Assigned without the use of jumpers and DIP switches. Resource settings for the configurable devices software can be changed without opening the computer case .



FLASH ROM ( Read Only Memory Flash)

FLASH ROM is a kind of EEPROM , the object information can be erased and written in blocks of bytes INSTEAD . This tend to make it faster than regular EEPROM . It aussi Requires less power to perform the procedure .

FLASH ROM is now Commonly used to store the BIOS information for personal computers . This Allows BIOS Makes the possibility of Providing updates via the Internet , and Potentially Allows users to gain access to new features That Were not supported by Their computer .

It is significant to get the Flash Program right the for each Particular BIOS. Do not use One That you -have a friend or an unknown site. Go to the manufacturer 's website and -have your BIOS Version and motherboard model number , serial number and the date at hand . Print and follow the instructions em Closely . Discover all the information about backing up and Restoring your previous BIOS if something go wrong shoulds .

Flashing the BIOS shoulds not be done every time an update is available. I think it shoulds be done When a required function is not supported and the only other recourse is a new motherboard , Because if things go wrong , It Could Be That you are the replacing . Do not flash just for the sake of flash . If you do not need to upgrade , do not flash your BIOS. Making a mistake in the process , lose power , or using the wrong image file Could be disastrous .

Motherboard

Motherboard

         The motherboard is the wide circuit board inside your computer case . It is sometimes called Expired the system board, motherboard , motherboard , or , less frequently, the flat map . Everything is connected to your computer system , Directly or Indirectly connects to the motherboard .

I am sour Everyone has heard of the CPU , or Central Processing Unit, Referred to as the " brain" of your computer . Well , the CPU is on the motherboard , and if it can be called Expired the brain of your computer , Then the motherboard is really the central nervous system . The motherboard contains the CPU , chip ROM BIOS (Basic Input / Output System) and CMOS configuration information. It Has slots for expansion cards Installing different adapt as your video card, sound card , network card, modem. The circuit board HAS connector for the keyboard as well as housing the keyboard controller chip . It Has slots for RAM Random Access memory of your system ( SIMM or DIMM) , and Provides the system chipset, controllers , and circuits underlying instrument (system bus) to tie everything together .

The motherboard , more or less , it's your computer . It kind of olefins your computer , scalability and expandability .

Mothers unintegrated

Non-integrated assemblies like mothers / O Port connectors I ( serial and parallel ports) , the connectors are gold cards paddle hard drives , the floppy controller and connectors, joystick connections , etc. . installed as expansion cards . This takes one or more expansion slots on the motherboard and Reduces the Amount of free space inside the computer case . Malthus , the individual motherboard is Relatively cheap to produce, Because The goal cost of manufacturing , testing and installing of expansion cards separately , there is an additional cost for the computer system . HOWEVER , if something shoulds go wrong with the various sub- assemblies , : such as a bent or broken pin in a connector or a defective chip controller, etc. . , You can fix the problem by replacing: the individual expansion card at a cost Relatively low .

Most older motherboards Were not integrated . Some of the later 486 system boards Began to Incorporate Some Of These assemblies right on the circuit board .

Motherboards integrated

Motherboards -have integrated assemblies That Are aussi installed as integrated expansion cards, or built right on the map . Serial and parallel ports , IDE and floppy drive, and the joystick all Directly connect to the motherboard . It is now standard on all 486 models and end above. Tend to release it from the interior of the housing and has Allows better airflow and accessibility . Systems are less expensive to Produce Because there is less material Involved , less setup and testing can be done at the same time . They are more expensive to repair , Because if you end up with a controller failure or broken pin , it means clustering a new motherboard (and, of course , Because of the added groups , the motherboard can be more expensive than icts homologous non- integrated ) . HOWEVER , integrated Specific dissertation sets are quite stable, and altho Generally problems can Occur , They tend to be quite rare.

Overall , integrated motherboard tend to be a good thing , as Opposed to the "mother Embedded.

Embedded motherboards

Cost and accessibility is a concern for Any Manufacturer . Make your more affordable, and more people will buy the product, Creating a larger market and Increase sales . Actually this is the idea behind integrated motherboards , and this is a motherboard onboard is an integrated card .

The reason I Distinguish Between the two is a matter of expansion , scalability and configuration. In an Effort to Reduce the cost ( and size ) of a computer system more odd , manufacturers -have Begun to Incorporate (or integration ) technologies : such as video , sound , networking and modems right on the system board . This Greatly Increases the cost of the motherboard , goal Reduces the cost of the system for the Entire Reasons Discussed Earlier we . In addition , you're pretty much stuck with what you have.

What if you decide you want to upgrade your audio or video technology , what happens if your modem or your card number along icts works overlooks ... you need a new ( expensive ) motherboard . But wait , the manufacturer indicates That You can update or bypass a Particular feature by Installing an adapt card and disabling the embedded device (sometimes ) . Well , this is Where some problems tends to Arise .

Firstly , how do you disable the device ? Some are disabled as soon as you install Reviews another device ( like a video card in an AGP slot) . Others shoulds be disabled by software install programs , or in the CMOS configuration of your system , or by setting jumpers on the motherboard Itself , or both ( and remember , Some can not be upgraded , BYPASSED or disabled at all ) .

SECONDLY , I can update the device I want , or am I limited ? Is there a list of compliant devices can I upgrade to? Many embedded systems can be tips very picky about the model and manufacturer of the device you use to replace That year integrated function .

Third , is there a place for the upgrade or replacement ? Remember , the manufacturer HAS built a device to save money and for reduce costs . More money has been saved by Reducing the number of expansion slots on the motherboard ?

Finally , the mother card Itself is more expensive Because of the embedded device. I would not damage the device cost reduction by disabling the device and install Reviews another ?

Another thing deception . A manufacturer can Say That Their integrated video technology has 4 MB of video RAM, expandable to , say 12MB . Usually this means clustering What Is That You have 4 MB of video memory ( All which is faster than regular system RAM) , and when to you upgrade than 12 MB ​​, it uses 8 MB ​​of RAM your system . Hmm ... Now your latest video technology uses regular system RAM INSTEAD of VRAM faster, 64 MB and your computer HAS only 56 MB of memory , 8 MB ​​Because WAS Allocated to video . Most manufacturers do not explain That One as well .

You May Find That you do a lot of desktop publishing or enjoy games, and decided you want to That update your video card to Improve Your graphics and Increase performance. With an embedded system , you May be limited to what you can do .

Make no mistake , the board might -have a recess in today 's market systems. Laptops and notebooks are getting smaller and lighter , and more like desktop computers featuring full . Some compromise is not only tolerated , but expected . You May need a basic business computer That Does nothing but the number of tightening or Accessing a database and ties to a small network . Maybe you are looking for a good computer market just to access the Internet or to play the odd game of solitaire . Maybe you play the odd game of work and you want to play your music CDs while you work . Maybe you are a first time buyer and you want all features thesis ! Embedded motherboards allow fast , powerful , feature-rich computer systems at a very reasonable cost . It's just significant to know Exactly what you get , and the various limitations and problems That can come later if you decide you want to Improve Some Of These characteristics .

From the sounds of it all , You Can Have the feeling That I ' m Not particularly crazy about embedded motherboards .

form factors

Form factors define the size , shape and placement of screws on the motherboard . Usually this is the technological advances That Have Been Made That thesis allow exchange so I guess aussi form factors define the technology to Some extent .

It is significant to Understand That none of these standards must be met ( except Perhaps the spacing Between the expansion slots) . So , if a manufacturer Decides to build a system board with the screw placement or different dimensions different from the norm , it is perfectly acceptable. Then this map Becomes the owner and can not be control by mittal by the original company. HOWEVER , if your motherboard adhered to one of the form factors , and you decided to upgrade your motherboard at a later date or replacement for Any Reason , Then All You Have to do is to buy Reviews another motherboard That follows this standard .

PC / XT

When IBM released icts first personal computer (PC), There Were No standards and mother tends to be a bit on the large size with more space than is really considers. In a short time , They Had Their computer Technologies Developed Extended ( XT ) Reducing the size of the motherboard to make it more compact and yet accept the different circuits and components for the system . The XT is Quickly Becoming a standard for motherboards in MOST clones That Were Developed at the time .

AT / AT baby

Computers are Quickly Becoming more and more Powerful with more system memory installed on the card , faster processors , and needed more circuits and components . IBM Had to Increase the size of Their boards to accept all components thesis and Developed the AT mother board . At 13.5 " X 12" , this form factor is Quickly Becoming a standard Followed by other manufacturers . Size , screw placement , positioning the expansion slot, and the odd placement of components WAS Followed Closely so That Some motherboard manufacturers Were worried about lawsuits . It was not uncommon to buy a computer from a manufacturer of system in place , with full documentation , order no contact information in the manual for the motherboard , Perhaps in fear of breach of copyright .

TA , HOWEVER , pretty much the industry standard Became Throughout the 80s and early 90s . As technology , circuits and components smaller and Have Become more integrated . Many companies -have Decided to Reduce the size of the motherboard again. Because AT has-been the norm for so Many Years They Have learned the location of expansion slots and positioning screws on a panel 13 " X 8.5 or 9 ." This Means That Could Be AT board mittal by a " Baby AT " or " mini -TA board and still fit in the same box.

Baby form factor all purpose mittal completely Call the AT and is still available , purpose HAS never been a true standard .

ATX

Because the baby form factor HAS never been a true standard , Many companies -have taken liberties with different dimensions and designs. The ATX form factor developed by Intel That hugs the baby Closely format. It brings together Some of the best ideas , engineering and design to a standard less expensive That is to develop, Allows better access component, and in Some respects , is faster and more stable.

ATX board Measures approximately 9.5 " X 12" and takes the baby on board and turns 90 degrees to the length of the board on the back of the computer case , Which Provides maximum space for extension of slots and I / O ports.

Ports of different I / O , USB connector and PS / 2 keyboard and mouse connectors are stacked or " Posed " and Directly wired to the motherboard . The lack of a cable connector Reduces radio interference and generation costs . The ATX motherboard aussi DETERMINED the number and location of mounting holes and uses a different power connection and Another (PS / 2 ) power .

The ATX standard aussi Provides a small form factor "Mini ATX " which cuts the size of a card to 8.2 " X 11.2" and Removes a row of holes These tips Will, in an ordinary case of ATX style .

The CPU (Central Processing Unit)

The CPU (Central Processing Unit)

The processor is the main chip ( integrated circuit) on the motherboard of the computer. They are of different sizes, shapes and packagings . Previous CPU (Central Processing Unit) came in DIP format, some 286s and early 386 were QSOPs (see integrated circuits) , but what you see are the most PGA square dish or chips ADAG .

The PGA chip used to be installed in a friction fit sleeve . Assembly and dis assembly to be done carefully to avoid bending or breaking the pins on the CPU. Firstly , it was necessary to align the chip. There is always a way to designate Pin # 1 on both the chip and the socket. There may be a point in a corner, or an arrow, or a small , silk screened '1 '. Usually, a CPU will have one of its beveled corners, and it must be aligned with the socket on the designated area. You must be sure that all the pins of the chip are straight and aligned correctly, and set the chip in the socket, you all pins are inserted in every hole . To install the chip, you press firmly and evenly . If the pins are not quite in their proper holes, or if you do not push down pins will bend sideways . Try to straighten the pins is not impossible, but usually results in the breaking . You learn very quickly to take your time and attention.

The withdrawal is another problem. Extractor chip is narrow and does not allow for as much control in trying to lift the chip (we're talking a good amount of friction holding the chip in ) . Some upgraded packages or ' turbo ' included , expanded special extractor chip that was better, but still did not provide much control. The best way is to carefully insert a narrow flat head screwdriver between the chip and the socket, being careful not to touch the pins underneath, lift and turn the chip a very minimal amount slightly . Then go to the side to side and do the same thing . When you work your way around the chip, it will come out pretty easy.

The problem has been recognized and a new Zero Insertion Force ( ZIF ) socket was developed. This decision makes a huge difference for removing and installing processors PGA and SPGA . It has a small handle or a lever on the side of the socket that the stall and raised , completely freeing the pins. You can simply lift the old CPU , fall into another , and pull the lever down, by inserting it into her little clip. No bent or broken pins , and no jagged edges on the CPU or the socket.

For the Intel Pentium , Pentium III , and some of its chips Celeron II processor is on a small printed circuit with the external cache , and enclosed or packed in a plastic cassette . This 'Slot 1' CPU clips in a style connector on the motherboard connector called " Slot 1 .

As should be obvious by now , you must match the CPU with the motherboard . Most motherboards accept more than one type of CPU as well as model, manufacturer , and speed is concerned, but they generally accept a socket type. This is a test that should be addressed and decided before you buy either . The motherboard manual will tell you what the different types of processors, it will accommodate . If you do not have a job, then visit the manufacturer's website. They provide this type of information . Major manufacturers include Intel CPU , Motorola , IBM, Advanced Micro Devices (AMD ) and Cyrix .

It should be noted that Intel CPU was before there were personal computers. They made the first chips for IBM PC. Most BIOS chips ( system I / O base ) on the first motherboards were developed based on the Intel architecture. Intel is still considered the No. 1 manufacturer and has set the standard for processors . Other CPU manufacturers and distributors tend to compare their product to Intel , saying that it is " comparable to Pentium II -350 " or is " better than -500 PIII ."

A specific processor it is described by the manufacturer, model and speed in megahertz ( MHz). The board of a computer system has a quartz crystal on it that emits a constant signal or beat like a metronome . Each is called a cycle time and time is measured in MHz or millions of cycles per second . A CPU runs at a multiple of the clock of the motherboard and it executes instructions are synchronized with each cycle of the internal clock speed of the CPU . So if your processor can execute one instruction every cycle , and you have a 500 MHz processor , while the chip can perform five hundred million instructions per second . Your heart will not beat that many times in a lifetime. Current technology by Intel and AMD gives us 1.5 GHz ( gigahertz ) processor this year. This is one and a half billion instructions per second!

The central processing unit is considered the "brain" of your computer. It controls and directs all activities of computer , transmission , reception and processing of data permanently . But as the "brain" of any project or organization , it relies heavily on its group and supportive counselors . There are many factors involved that are related to the CPU and affect the speed and performance of your machine. Some of these factors include :

There is a math co processor present and whether it is internal or external.

Speed ​​system clock and CPU . The amount of internal memory and external cache cache available.

Types of Network

Types of Network

There are the various types of Network but 3 important types are given below.

1.      LAN. (Local Area Network).

2.      MAN (Metropolitan Area Network).

3.      WAN (Wide Area Network).

LAN:-
Diagram:-

Definition:    

LAN stands for Local Area Network. The network of computers inside a building, office, or small surrounding area is called LAN.

Example:

1.      In lab.

2.      In Collage.

3.      In hospital.

Purpose of LAN:-

 There are some main Profit of LAN is:

·        To share expensive Input/output (I/O) devices like printer and etc.

·        To share Information, files and databases.

·        To share expensive Software.

·         To allows users of the network to communicate with each other.

MAN:-
Diagram:-

Definition:             
MAN stands for Metropolitan Area Network.  A network of computers in a city, organization and specific area called MAN.  

Example:

1.      In Factory.

2.      In City just like (New York, Masco, Islamabad, Delhi etc ).

3.      In Franchises.

WAN:
Diagram:-

Definition:             
WAN stands for Wide Area Network. The network of computers that connects different offices, cities and countries is called WAN.

EXAMPLE:

            Internet is the biggest example of WAN.

            

Networking

Networking

                The computer network is a phenomena or system in which two or more than two computers are connected (which specific medium) each other for shearing information and resources.

                In a computer network of computer different computers are connected with each other through cables, satellite or telephone lines.
 

Explanation:-

       
  Through a network, we can share information with the users of user’s of other computer and we can also shear resources.

                Many computers of the network can use one printer, different costly software can also be sheared be a networking.

Example:-

1.       A network in Computer lab.

2.       A network in organization.

3.       A network in hospital.

4.       The biggest example of network is Internet.

Advantages of Networking:-

               
There are few common advantages of Networking.

·         Data and information and expensive software sheared with different users of the network.

·         Resources like printer, CD Drive, Hard disk etc can also be sheared.

·         By shearing Expensive resources we can save smart amount of cash.

·         Internet is the best example of Network we can sheared any information and data, movies, songs and much more Knowledge anybody in the world by using it.

·         We can send massage to the many users of a network without any cash or money and at a rapid rate.

·         Working speed can be increase. The above of some most common advantages of networking there are various advantages of networking.

SEO Search Engine Optimization.

SEO Search Engine Optimization.

That’s process of Marketing like Product, Websites etc.

Now a these days SEO is very easy and naturally.

SEO based just two Department.

1  is known Onpage.

2 is known Offpage.

Onepage SEO:

Onpage SEO based in html Head Tags all meta tags used in head tags. Just like <head>meta tags</head>

☻Title

Title tag used to inform Search engine what is  your website topic.

Title tag is given below.

<title>your blog title here</title>

☻Description

make a short description about your blog contents. But only first 15-35 characters will be visible at the search results. So make it short and Beautiful/nice.

Description tag is given below.

<meta content='your blog description' name='description'/>

☻Keywords

 keywords are the most important tag after description. This tag help search engine to specify the keywords to show your blog/site as a result. Many search engines are just mention about first 60-100 characters of Keyword.

Keywords tag is given below.

<meta content='your blog keywords' name='keywords'/>

☻Author

Author tag to show just identifies the author. Also Author tag not is very important tag at SEO. But this tag helps to make your site/blog professional.

Author tag is given below.

<meta content="your name here" name="author"/>                               

☻Copyright

Copyright code to identify your site/blogs copyright information because another optimizer do not copy your content/picture/software and etc.

Copyright tag is given below.

<meta content="2011, your brand" name="copyright"/>

☻Revisit

Every sites like blogs are always adding, changing new posts/article/picture/software so to notify search engines about new updates this tag is very important. You can edit or change the time that you need the report to visit. If you use this tag I suggest 15-30 days.

Revisit tag is given below.

<meta content="31 days" name="revisit-after"/>

☻Expires

Express tag is used to the search engines know when your article will expire by adding Express tag. "never" is best for a blog/site.

Express tag is given below.

<meta content="never" name="expires"/>

☻Distribution

Distribution tag tells about which group of users your blog/site will helpful/useful for. There are some common options for this tag.

Distribution tag is given below.

<meta content="global" name="distribution"/>

global : for everyone

local : for regional users

ui : for internal use

☻Robot

Robot tag is a  guide to the search engine robots about indexing .Robot tag are some common options.

<meta content="index" name="robots"/>

index : index this page

noindex : don't index this page

nofollow : dont index any hyper-linked page

none : (noindex,nofollow)

☻Rating

Rating tag is that gives a rating for the appropriateness for kids.  Rating tag are some common options for this too.

Rating tag is given below.

<meta content="general" name="rating"/>

you can change general into " mature, restricted, and 14 years. " it depends on your page contents.

Offpage SEO:

You can submit Your Site to Every Search Engines

Web search engines (like Google, bing  etc) automatically add new websites/blog to their search index every time they crawl the web.

If your web site is new and unknown website, so you can take some time before your site is "discovered".

Luckily most search engines invite you to submit your site/blog: *

Best Search Engines.

Google:http://www.google.com/addurl.html

Yahoo: http://search.yahoo.com/info/submit.html

Bing:http://www.bing.com/webmaster/SubmitSitePage.aspx

Open Directory: http://www.dmoz.org/help/submit.html