Sunday 18 March 2007

Uses of the Internet

Today the internet has evolved into a powerful world tool. Many people are using it as a substitute to many things such as replacing mail, with e-mail and supermarket shopping with e-commerce. E-mail is considered to be one of the key features of the internet, it is actually older than the internet as it started off in 1965 as a way for multiple users to communicate via a time sharing a mainframe computer.
A way to find information you want is called a search engine,the first search engine was the Archie search engine from McGill university in 1990. Over time there were more and more search engines made available and also web directories were available. The first ever full test web search engine was valled web crawler in 1994. Modern search engines are now based on relevance searches such as google (1998).
The futre of the internet is predictably huge, according to recent trends over the past few years.

Commerce

In the early years commercial use of the internet was forbidden becasuse the definition ofcommercial use was inclear but UUCP net and x.25 had no restrictions, this would lead to the barring of UUCPnet of ARPANET andNSFnet.
During the late 80's the first ISPs were formed. The first dial-up ISP opended up in 1989 (world.std.com). Universtiys were not impressed with this because there was non-educational use of their networks going on. Eventually, commercial ISPs brought prices low enough so schools could afford to have further researched education.
In 1990 ARPANET was overtaken and replaced by newer network technology. In 1994 NSFnet was renamed ANSNET (Advanced Networks and Services) and was allowing non profit company access, so it lost its backbone of the internet. Regional NAPs (Network Access Points) was the primary interconnections between the many networks and the final commercial restictions ended.




(Click to enlarge)

Saturday 17 March 2007

TCP/IP

Transmission Control Protocol (TCP a.k.a TCP/IP) Is a protocol of the internet protocol suite. Using TCP, networked hosts can make connections to each other, so tehy can transfer steams of data. The protocol guarantees reliable and in order delivery of data from sender to receiver. TCP also makes out data for a few connections by Web server, e-mail servers etc running on the same host.
TCP supports many of the Internet's most popular protocols and resulting applications, including the World Wide Web, e-mail, File Transfer Protocol and Secure Shell.

Networks that led to the internet

X.25
Packet switching network standards were developed by the International Telecommunication Union in the form of X.25. X.25 formed the basis for the SERCnet network between British academic and research sites In 1974. The initial ITU Standard on X.25 was approved in March 1976. The British post office, and Tymnet collaborated to create the first international packet switched network. This network grew from Europe and the US to cover Hong Kong and Australia by 1981.
X.25 would be used for the first dial-in public access networks, like Compuserve and Tymnet. In 1979, CompuServe became the first service to offer e-mail capabilities and technical support to PC users. The company broke new ground again in 1980 as the first to offer real time chat with its CB Simulator.

UUCP
in 1979 two students at Duke university named Tom Truscott and Jim Ellis used Bourne shell scripts to transfer news and messages on a serial line. UUCP net also created gateways and links between FidoNet and dial up BSS hosts. UUCP networks spread quickly because of lower costs, Also because of the use of leased lines, x25 links or even ARPANET. the number of UUCP hosts had grown to 550 by 1983 and then nearly doubling by 1984

Once upon a time...

...In the mid 20th century before inter-networking, most networks were restricted to only allow communications between stations on a network. Some networks had gateways or bridges, but these bridges were often limited or built specifically for a single use. One computer method at the time was on the mainframe computer method. This method was used in the 1950's project RAND.

ARPA
J.C.R. Licklider was appointed the head of DARPA in 1962. While here he formed an informal group within DARPA to further computer research, as part of his role in DARPA he had installed three network terminals. One for System Development Corporation in Santa Monica, one for Project Genie at the University of California, Berkely and one for the Multics project shopping at MIT. Licklider would need inter-networking for the problems these netorks caused.

Packet Switching
As well as the inter netowkig problem, there was also a problem with connecting separate physical networks to form one logical network so during the 1960's a team of three men, Donald Davies, Paul Baran and leonard Kleinrock, developed Packet Switching. The notion that the Internet was developed to survive a nuclear attack has its roots in the early theories developed by RAND. Baran's research had approached packet switching from studies of decentralisation to avoid combat damage compromising the entire network.