Page 93 - DLIS408_INFORMATION_TECHNOLOGY-APPLICATIONSL SCIENCES

Information Technology and Application

characteristics of LANs, in contrast to wide area networks (WANs), include their usually higher data-
Notes
transfer rates, smaller geographic area, and lack of a need for leased telecommunication lines.
Figure 8.1: LAN Network-Linking individual work-
stations, usually less than a mile apart

Computer

Printer
Switch

Router

ARCNET, Token Ring and other technology standards have been used in the past, but Ethernet
over twisted pair cabling and Wi-Fi are the two most common technologies currently in use.
As larger universities and research labs obtained more computers during the late 1960s, there was
an increasing pressure to provide high-speed interconnections. A report in 1970 from the Lawrence
Radiation Laboratory detailing the growth of their “Octopus” network gives a good indication of
the situation.

Did u know? Cambridge Ring was developed at Cambridge University in 1974 but was
never developed into a successful commercial product.
Ethernet was developed at Xerox PARC in 1973-1975, and filed as U.S. Patent 4,063,220. In 1976,
after the system was deployed at PARC, Metcalfe and Boggs published a seminal paper, “Ethernet:
Distributed Packet-Switching for Local Computer Networks.”
ARCNET was developed by Data point Corporation in 1976 and announced in 1977. It had the first
commercial installation in December 1977 at Chase Manhattan Bank in New York.

Standards Evolution
The development and proliferation of CP/M-based personal computers from the late 1970s and
then DOS-based personal computers from 1981 meant that a single site began to have dozens or
even hundreds of computers. The initial attraction of networking these was generally to share disk
space and laser printers, which were both very expensive at the time. There was much enthusiasm
for the concept and for several years, from about 1983 onward, computer industry pundits would
regularly declare the coming year to be “the year of the LAN”.
In practice, the concept was marred by proliferation of incompatible physical Layer and network
protocol implementations, and a plethora of methods of sharing resources. Typically, each vendor
would have its own type of network card, cabling, protocol, and network operating system. A
solution appeared with the advent of Novell NetWare which provided even-handed support for
dozens of competing card/cable types, and a much more sophisticated operating system than
most of its competitors. Netware dominant in the personal computer LAN business from early
after its introduction in 1983 until the mid 1990s when Microsoft introduced Windows NT Advanced
Server and Windows for Workgroups.
Banyan Vines had comparable technical strengths, but Banyan never gained a secure base. Microsoft
and 3Com worked together to create a simple network operating system which formed the base of

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