Information Technology Reference
In-Depth Information
work connecting four research computers—at the University of
California at Los Angeles and at Santa Barbara, at SRI
International, and at the University of Utah. Funding for this net
work came through the Advanced Research Projects Agency
(ARPA) within the DoD, and this network was therefore called
ARPAnet. Through the 1970s, the number of locations attached to
this DoD network expanded gradually, and people connected to
these computers also found other types of uses for the network, be
yond those initially envisioned by the DoD. For example, file trans
fer with FTP was developed in 1971.
In the 1980s, the initial network established by the DoD com
bined with other networks funded through the U.S. National
Science Foundation (NSF). In particular, the main network, or
backbone,
involved a few main computer centers, or
nodes
, and
other institutions obtained access by connecting to these centers (or
to institutions that in turn had connections to the backbone cen
ters). Overall, these inaugural connections might be envisioned as a
web or expanded star network, with a backbone computer in the
center, a few connections to that center for “firsttier” institutions,
connections to the firsttier computers to form a “secondtier,” and
so forth. Thus, when a new institution wanted to establish a connec
tion to this network, it would first identify what other organizations
in the area already had a connection. Then, the new institution
would negotiate to run (or lease) one or more cables from its own
computers to the alreadyconnected organization. Typically, institu
tions in an area might be connected to the same backbone node—
either directly or through its neighbors. Connectivity to other re
gions typically involved going through backbone nodes.
Computer connectivity was becoming increasingly useful, but
funding came largely from the NSF, which is chartered to conduct
scientific research and development. With this focus, the NSF lim
ited connections to the network to research organizations, scientific
laboratories, and academic institutions. Commercial traffic was not
allowed. For example, email was first developed in 1972, when
Ray Tomlinson at BBN wrote the first basic software to send and
receive email messages. In the mid 1970s, email emerged as a very
popular application, and folks at universities could communicate
over the NSF network via email. This network, however, was not
connected to commercial networks that had emerged separately.
Thus, a scientist at a research university might be able to email a
research assistant at another university, but not a colleague who
