Programming Embedded Systems, 2nd Edition

Chapter 12. Embedded Linux Examples

Ty Webb: Don’t be obsessed with your desires, Danny. The Zen philosopher, Basho, once wrote: “A flute with no holes is not a flute...and a doughnut with no hole is a Danish.” He was a funny guy.

—the movie Caddyshack

I n this chapter, we will explore some examples using embedded Linux. The examples in this chapter are similar to (or in some cases the same as) the eCos examples we covered in the previous chapter. The idea here is to get an introduction to embedded Linux and understand some basic operating system functionality.

Introduction

The embedded Linux examples demonstrate certain basic APIs for various operations. Additional APIs exist that offer other functionality. You should research the additional APIs on your own to determine whether there are other, better ways to perform the operations necessary for your particular embedded system.

One aspect of Linux you need to be familiar with is its thread model. The Linux API conforms to the key POSIX standard in the space, POSIX 1003.1c, commonly called the pthreads standard. POSIX leaves many of the implementation details up to the operating system implementer. A good source of information on pthreads is the book Pthreads Programming, by Bradford Nichols, Dick Buttlar, and Jacqueline Farrell (O’Reilly).

The version of embedded Linux used on the Arcom board is a standard kernel tree (version 2.6) with additional ARM and XScale support from the ARM Linux Project at http://www.arm.linux.org.uk ...