\chapter{Introduction}

HelenOS is a development operating system intended to
be a testbed for research in the field of operating
systems and system-level programming. This manual is
a guide for building, running and enhancing HelenOS.

The system, as any other operating system, can be divided
into platform independent and platform dependent parts.
A user space program could be written in such
a way that it can be compiled and executed on any
of the platforms HelenOS supports without any modifications.
However it might work as a device driver or perform
other special tasks and thus become platform dependent.

\section{Structure of HelenOS}

The HelenOS operating system consists of three major parts:

\begin{itemize}
 \item Kernel
 \item User space layer
 \item Boot infrastructure
\end{itemize}