Page 51 - DCAP104_EXPOSURE_TO_COMPUTER_DISCPLINES

Exposure to Computer Disciplines

Notes Distributed Operating System: An operating system that manages a group of independent
computers and makes them appear to be a single computer is known as a distributed operating
system. The development of networked computers that could be linked and communicate
with each other, gave rise to distributed computing. Distributed computations are carried
out on more than one machine. When computers in a group work in cooperation, they make
a distributed system.
Embedded System: The operating systems designed for being used in embedded computer
systems are known as embedded operating systems. They are designed to operate on small
machines like PDAs with less autonomy. They are able to operate with a limited number of
resources. They are very compact and extremely efficient by design.

Windows CE, FreeBSD and Minix 3 are some examples of embedded operating systems.
The operating systems thus contribute to the simplification of the human interaction with the
computer hardware. They are responsible for linking application programs with the hardware,
thus achieving an easy user access to the computers.

3.3 The User Interface

The user interface is the space where interaction between humans and machines occurs. The
goal of interaction between a human and a machine at the user interface is effective operation
and control of the machine, and feedback from the machine which aids the operator in making
operational decisions. A user interface is the system by which people (users) interact with a
machine. The user interface includes hardware (physical) and software (logical) components.
User interfaces exist for various systems, and provide a means of:
• Input, allowing the users to manipulate a system, and/or

• Output, allowing the system to indicate the effects of the users’ manipulation.
The following types of user interface are the most common:

• Graphical User Interfaces (GUIs)
• Command-Line Interfaces

3.3.1 Graphical User Interfaces (GUIs)
Most modern operating systems, like Windows and the Macintosh OS, provide a graphical
user interface (GUI). A GUI lets you control the system by using a mouse to click graphical
objects on screen. A GUI is based on the desktop metaphor. Graphical objects appear on a
background (the desktop), representing resources you can use.

Icons are pictures that represent computer resources, such as printers, documents, and programs.
You double-click an icon to choose (activate) it, for instance, to launch a program. The Windows
operating system offers two unique tools, called the taskbar and Start button. These help you
run and manage programs.

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