Web Engineering( 3 Sep. 2012 )
A network of networks is called Internet
the world wide web (abbreviated as www or w3, commonly known
as the web), is a system of interlinked hypertext
documents accessed via the internet. with a web browser,
one can view web pages
that may contain text, images, videos, and other multimedia,
and navigate
between them via hyperlinks.Using concepts from his earlier hypertext systems
like enquire,
british
engineer
and computer scientist sir tim
berners-lee, now director of the world wide web consortium (w3c), wrote a
proposal in march 1989 for what would eventually become the world wide web. at cern, a european research
organization near geneva
situated on swiss and french soil, berners-lee and belgian computer scientist robert
cailliau proposed in 1990 to use hypertext "to link and access
information of various kinds as a web of nodes in which the user can browse at
will", and they publicly introduced the project in december of the same
year.
Client
A client is an application or system that accesses a service
made available by a server. The server is often (but not always) on another
computer system, in which case the client accesses the service by way of a
network. The term was first applied to devices that were not capable of running
their own stand-alone programs, but could interact with remote computers via a
network. These dumb terminals were clients of the time-sharing mainframe
computer.
The client–server model is still used today. Client and
server can run on the same machine and connect via Unix domain sockets, or
other inter-process communication techniques such as shared memory, or named
pipes. Using Internet sockets a user may connect to a service operating on a
possibly remote system through the Internet protocol suite. Servers set up
listening sockets, and clients initiate connections that a server may accept.
Web browsers are clients that connect to web servers and retrieve web pages for
display. Most people use email clients to retrieve their email from their
internet service provider's mail storage servers. Online chat uses a variety of
clients, which vary depending on the chat protocol being used. Multiplayer
online games may run as Game Clients on each local computer.
Server
A program that can accept a remote request and can send back
response accordingly. For example Tomcat, IIS, oracle, mysql, informax
In most common use, a server is a physical computer (a computer hardware system) dedicated to running one or more services (as a host), to serve the needs of the users of other computers on the network. Depending on the computing service that it offers it could be a database server, file server, mail server, print server, web server, gaming server, or some other kind of server.
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients". The clients either run on the same computer or connect through the network.
In most common use, a server is a physical computer (a computer hardware system) dedicated to running one or more services (as a host), to serve the needs of the users of other computers on the network. Depending on the computing service that it offers it could be a database server, file server, mail server, print server, web server, gaming server, or some other kind of server.
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients". The clients either run on the same computer or connect through the network.
Port
Just a number that is going to be mark on a server
type program.Its range is 1 - 65535 but recommended use is except 1 - 1024
because this may be used for operating system.
In computer networking a port is an
application-specific or process-specific software construct serving as a
communications endpoint in a computer's host operating system. A port is
associated with an IP address of the host, as well as the type of
protocol used for communication. The protocols that primarily use the ports are
the Transport Layer protocols, such as the Transmission Control Protocol (TCP) and
the User Datagram Protocol (UDP) of the Internet Protocol Suite. A port is
identified for each address and protocol by a 16-bit number, commonly known as
the port number. The port number completes the destination address for a
communications session. Thus, different IP addresses or protocols may use the
same port number for communication, e.g. on a given host or interface UDP and
TCP may use the same port number, or on a host with two interfaces, both
addresses are associated with a port having the same number.
Socket
WebSocket is designed to be implemented in web browsers
and web servers,
but it can be used by any client or server application. The WebSocket Protocol
is an independent TCP-based protocol. Its only relationship to HTTP is that its
handshake is interpreted by HTTP servers as an Upgrade request.[2]
The WebSocket protocol makes possible more interaction between a browser and a
web site, facilitating live content and the creation of real-time games. This
is made possible by providing a standardized way for the server to send content
to the browser without being solicited by the client, and allowing for messages
to be passed back and forth while keeping the connection open. In this way a
two-way (bi-directional) ongoing conversation can take place between a browser
and the server. A similar effect has been achieved in non-standardized ways
using stop-gap technologies such as Comet.
In addition, the communications are done over the regular
TCP port number
80, which is of benefit for those environments which block non-standard
Internet connections using a firewall. WebSocket protocol is currently
supported in several browsers including Internet
Explorer, Safari, Firefox
and Google Chrome.
WebSocket also requires web applications on the server to be able to support
it.
Stream
In computing, the term stream is used in a number of
ways, in all cases referring to a sequence
of data elements made available over time. A stream can be thought of as a conveyor belt
that allows items to be processed one at a time rather than in large batches.
On Unix
and related systems based on the C language, a stream is a source or sink
of data, usually individual bytes or characters. Streams are an abstraction
used when reading or writing files, or communicating over network sockets. The standard
streams are three streams made available to all programs.
Pipelines can also be understood as
streams as well as any unlimited (non-packaged) information that is inserted by
a device.
In the Scheme language and some others, a stream
is a lazily evaluated or delayed sequence of data
elements. A stream can be used similarly to a list, but later elements are only
calculated when needed. Streams can therefore represent infinite sequences
and series.[1]
See Stream (type theory).
Protocol
protocol is a system of digital message formats and rules
for exchanging those messages in or between computing
systems and in telecommunications. A protocol may have a
formal description.
A protocol definition defines the syntax, semantics,
and synchronization of communication; the specified behavior is typically
independent of how it is to be implemented. A protocol can therefore be
implemented as hardware or software or both.
The Internet Protocol is used in concert with other
protocols within the Internet Protocol Suite. Prominent members of which
include:
User Datagram Protocol (UDP)
Hypertext Transfer Protocol (HTTP)
Post Office Protocol (POP3)
File Transfer Protocol (FTP)
Other instances of high level interaction protocols are:
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