Graphics Programs Reference
In-Depth Information
completed its mission (Clark, 1996; Engst, 1994;
Leiner, 1997).
The TCP/IP architecture proposed by Vinton
Cerf of Stanford and Bob Kahn of BBN consists
of two major components. IP provided for ad-
dressing and forwarding of individual packets of
data, while TCP was used for flow control and to
recover any lost data packets (Krol, 1994). TCP/IP
sends information in small packets of information,
which also contain routing information such as
the destination. A packet may pass through 30 or
more computers before it reaches its final desti-
nation. The software protocol was public domain
software. The US Defense Department adopted it
in 1980 and it was universally adopted in 1983.
An alternate protocol known as User Datagram
Protocol (UDP) was developed later on, specifi-
cally for those applications that did not use TCP/
IP (Krol, 1994).
In order to connect one computer to another,
they must first be able to locate each other. The
initial computers on the WAN, also known as Inter-
face Messaging Processors (IMFs) made use of a
protocol known as Telecommunications Network,
or TELNET, for short. The TELNET protocol was
defined by RFC0015 in 1969. TELNET was one
of the first internet standards, and is for the most
part, text-only, and is accessible without the aid of
a user interface. One of the earliest experiments in
TELNET was conducted by Lawrence G. Roberts,
with the help of Thomas Merrill, who connected
a TX-2 computer in Massachusetts to a Q-32 in
California using a low-speed dial up phone line
(Clark, 1996; Engst, 1994; Leiner, 1997). This
experiment helped prove that remotely located
computers could work well together, receiving
data and running programs.
Various control devices such as routers soon
developed, based in part on existing telephone
company technology for 'switching' connections.
Electronic Mail (email) was first used effectively
on ARPAnet in 1971, and was developed by Ray
Tomlinson. This allowed users to sent a digital
'letter' wrapped by an 'envelope' containing to
and from addresses, and other information such as
the size of the message (Shirky, 1994). The email
THe BIRTH OF THe mODeRN
DAY INTeRNeT
The Internet as we now know it began with AR-
PAnet in 1969 under a United States Government
contract. The two main purposes were to allow
for shared research between universities and other
institutes, and to provide support for the Depart-
ment of Defense in the event of nuclear attack.
In the early years, computers, whether connected
locally within a building, or remotely via telephone
line, remained in the domain of computer experts,
engineers and scientists. There were no home or
personal computers to speak of. In order to realize
the promise of the Galactic Network , there was
much work to be done.
The first step was to design and construct a
Wide Area Network (WAN). The WAN took close
to two years to develop and when completed in
December of 1969, connected the main computers
at UCLA, the Stanford Research Institute, and the
University of Utah via telephone lines, and repre-
sents the initial foray into networking. Of course,
there was a need to establish common hardware
and software protocols in order to facilitate effec-
tive inter-networked computer communications.
Among the most important was the ability to
identify the 'address' of a device, and then control
the connection. ARPAnet used Network Control
Protocol (NCP), which was eventually super-
seded by the far superior Transmission Control
Protocol/Internet Protocol (TCP/IP), originally
implemented in 1983 and still in use today. TCP/
IP is a multi-layer protocol that resolves various
issues and allowed for connectivity between the
original ARPAnet WAN and the other networks
that had also emerged. This allowed for true global
connectivity, and eventually evolved into what
we call the internet (Clark, 1996; Engst, 1994;
Leiner, 1997; Shelley et al., 1998).
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