The primary means of communication with computers earlier had been through commandbased
interfaces. In command interfaces, users have to learn a large set of commands to
get theirjob(s) done. In earlier computer systems paper tapes, cards and batch jobs were
the primary means of communicating these commands to the computers. Later, timesharing
systems allowed the use of CRT terminals to interact/communicate with the
computer. These early systems were heavily burdened by users trying to share precious
computer resources such as CPU and peripherals.
The batch systems and time-sharing led to command-driven user interfaces. Users had
to memorize commands and options or consult a large set of user manuals. The early
mainframe and minicomputer systems required a large set of instruction manuals on
how to use the system. In some systems, meaningful terms were used for command
names to help the end-user. But in other systems the end-user had to memorize several
sequences of keystrokes to accomplish certain tasks.
Early users of computes were engineers and what we now call expert users; user
who had a lot of interest in knowing more about computer systems and the technology.
Command line interfaces were acceptable to the majority of these users. In the 1970s,
computers were introduced to a new class of users: secretaries, managers and nontechnical
people. These new users were less interested in learning computer
technology and more interested in getting their jobs done through the machine. The
command-based interfaces caused many of these new users to develop computer
phobia. Imagine the thought of memorizing commands made up of "Control-Alt-Del" to
boot the system.
To make life easier for the end -user, a large collection of devices have been
invented to control, monitor and display information. The early (and still widely used)
peripherals are the keyboard and the video terminal. But, it was not until the late
70s, that research projects at some universities led to the invention of pointing
devices and windowing systems. The mouse and joystick were among some of the
few pointing devices that were invented in this period. Also, research pioneers
invented the notion of splitting the screen to allow multiple windows and direct
manipulation of objects.
In the 70s, researchers designed powerful new workstations armed with graphical
user-interfaces. The basic assumption of these new workstations was that one user
could have a powerful desktop computer totally dedicated to that user's task. Thus,
the computer is not only used to perform the task, but can also provide a much more
intuitive and easy-to-use environment. In this unit we will examine the common
GUIs.
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