Distributed Systems Development - Autonomics Development: A Domain-Specific Aspect Language Approach - page 7

2 Distributed Systems Development

2.1 Introduction
Computer systems used to be expensive standalone self-contained entities, each
with its own disk storage, line printers, terminals and other peripherals. The
introduction of the minicomputer made computers cheaper and more widespread,
which led to the requirement to share information between them. This requirement
led to the development of early computer networks, such as the Unix-to-Unix copy
program (UUCP) in 1976 and its subsequent release in AT&T Version 7 Unix in
the same year.
The development of Berknet by Eric Schmidt in 1978 at the University of Cal-
ifornia, Berkeley and its subsequent distribution in Version 7 Unix for the PDP-11
minicomputer allowed users to send and receive email, transfer files and print
remotely [88]. In 1980, Bolt, Beranek, and Newman were contracted by the Amer-
ican Department of Defense to implement the TCP/IP protocol for BSD UNIX.
The release of 4.2BSD in August 1983 with its implementation of TCP/IP and
the BSD sockets programming model, coupled with the growth of local area net-
works based mainly on Ethernet, allowed computers to connect to the ARPANET,
the predecessor to the Internet, which led to the enormous growth of networked
systems in the early 1980s [96].
The introduction of the personal computer and its subsequent ability to con-
nect to TCP/IP networks using the Winsock API, based on BSD sockets, led to
a huge increase in the number of networked machines and distributed systems
began to become mainstream. Automated teller machines, airline reservation sys-
tems, file sharing, file transfer, centralised database access, email and various other
distributed systems were introduced.
The subsequent invention of the web browser and HTTP protocol led to the
World Wide Web and the enormous explosion in the number of distributed systems
that we see today. With the continued increase in processing power and fall in
component prices, computing is promising to become even more widespread and
we may well see the vision of ubiquitous computing [120] being met in the future.
Yet, while distributed systems have become mainstream, distributed systems de-
velopment remains dicult and little advancement has been made since the initial
concepts were developed decades ago.