Information Technology Reference
In-Depth Information
Chapter 1
Introduction
"Everything I need to know I learned in kindergarten." { Robert Fulgham
How do we construct reliable, portable, ecient and secure computer sys-
tems? An essential component is the computer's operating system | the soft-
ware that manages a computer's resources.
First, the bad news: operating systems concepts are among the most complex
topics in computer science. A modern general-purpose operating system can run
to over 50 million lines of code, or in other words, more than a thousand times as
long as this textbook. New operating systems are being written all the time. If
you are reading this textbook on an e-book reader, tablet, or smartphone, there
is an operating system managing the device. Since we will not be able to cover
everything, our focus will be on the essential concepts for building computer
systems, ones that every computer scientist should know.
Now the good news: operating systems concepts are also among the most
accessible topics in computer science. Most of the topics in this topic will seem
familiar to you | if you have ever tried to do two things at once, or picked
the wrong line at a grocery store, or tried to keep a roommate or sibling from
messing with your things, or succeeded at pulling o an April Fool's joke. Each
of these has an analogue in operating systems, and it is this familiarity that
gives us hope that we can explain how operating systems do their work in a
single textbook. All we will assume of the reader is a basic understanding of
the operation of a computer and the ability to read pseudo-code.
We believe that understanding how operating systems work is essential for
any student interested in building modern computer systems. Of course, every-
one who uses a computer or a smartphone or even a modern toaster uses an
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