Information Technology Reference
In-Depth Information
What is an
operating
system and
what does
it do?
WHEN DISCUSSING COMPUTERS, we often hear comments
such as “I use a Windows machine,” “I like Linux,” “My Macintosh
runs OS X,” or “Windows XP seems more reliable than Windows NT.”
Similarly, various computer users or salespeople may tout the advantages
of Windows XP, Windows NT, Linux, or Mac OS X. Unfortunately,
such statements often dwell on esoteric details, reflect subjective personal
preferences, or involve lengthy technical discussions.
For the general computer user, discussing details about operat
ing systems may seem obtuse and obscure. Every computer seems to
have a Windows, Linux, Macintosh, or other operating system, but
why do operating systems exist at all, and how are they similar or
different from each other? This chapter addresses such basic ques
tions and leaves the lengthy technical discussions and opinions for
others at another time.
Operating systems
have evolved over several decades, so it is
helpful to take a historical perspective when trying to understand
them. We have already noted that a computer functions by follow
ing detailed instructions. In the early days of computers, every user
had to supply absolutely every detail of information that a computer
would need to run. If a program was to read data from a keyboard,
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