<preface>
<title>Welcome to &os9level;!</title>
<titleabbrev>Introduction</titleabbrev>
<para>
At the heart of your &make; is an amazing device: the
&CPU; central processing unit (CPU).  When introduced in 1980, This
microprocessor offered sophisticated features that were only
found only on much larger and costly computers. Even today, it is
architecture is considered feature-rich.  The OS-9 operating system
was designed around the 6809 microprocessor to provide an extremely
efficient and powerful operating system.
</para>
<para>
The foundation of a computer's software system is its
<emphasis>Operating System</emphasis> or "OS". It is the master control
program that interfaces all other software to the system's hardware. Some
of the things it must do are performing input and output operations,
coordinating memory use, and many other "housekeeping" functions. All
other software - programming languages, applications programs, etc. -
live in your computer's memory along with the OS and depend on it to
communicate with you using the keyboard and display and to store and
retrieve data on disks, etc. Because virtually all other software relies
on the OS, your computer's performance depends on the capabilities and
efficiency of its OS.
</para>

<para>
OS-9's overall structure was based on the famous UNIX<footnote id="unixdesc">
<para>
UNIX is an operating system designed by Bell Telephone
Laboratories, which is becoming widely recognized as a standard for
mini and micro operating systems because of its versatility and
elegant structure.
</para>
</footnote>
operating system, which has been widely acclaimed as the operating
system of the future because of its versatility, logical structure,
and friendly user commands. The OS-9 family of advanced software is
not only more powerful than most other microcomputer scftware - it
is also much easier to learn and use.
</para>
<para>
Some of the advanced OS-9 features you'll learn about in this
book are:
</para>
<orderedlist numeration="arabic">

<listitem><para>Friendly UNIX-like
user interface and environment</para></listitem>

<listitem><para>Multiuser/Multitasking Real-Time Operating System</para></listitem>

<listitem><para>Extensive support for structured, modular programming</para></listitem>

<listitem><para>Device-independent interrupt-driven input/output system</para></listitem>

<listitem><para>Multi-level directory file system</para></listitem>

<listitem><para>Fast Random-Access File System</para></listitem>

<listitem><para>Readily Expandable and Adaptable Design</para></listitem>

</orderedlist>
<para>
If you don't know what some of these thing mean yet - don't
worry. As you explore OS-9 you'll soon learn how they enhance the
capability of your &make; and make it so much easier to use
in almost any application.
</para>
<para>
OS-9 has many commands and functions - definitely more than
you can learn in an evening! The best way to become an OS-9 expert
is to study this manual carefully, section-by-section, taking tire
to try out each command or function. Because many functions affect
others, you'll find this manual extensively cross-referenced so you
can skip ahead to help you understand a new topic. Taking the time
to study this book will certainly increase your knowledge and
enjoyment of OS-9.
</para>
<para>
But if you can't wait, at least read the rest of this chapter,
scan the command descriptions in a later chapter, and have fun
experimenting!
</para>
</preface>