文件名称：Apress.Pro.Linux.Embedded.Systems.Dec.2009
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更新时间：2013-02-17 10:44:27
Linux Embedded
Apress.Pro.Linux.Embedded.Systems.Dec.2009 Linux is an incredible piece of software. It’s an operating system that’s just as at home running on IBM’s zSeries supercomputers as it is on a cell phone, manufacturing device, network switch, or even cow milking machine. What’s more incredible is that this software is currently maintained by thousands of the best software engineers and it is available for free. Linux didn’t start as an embedded operating system. Linux was created by a Finnish university student (Linus Torvalds) who was smart enough to make his work available to all, take input from others and, most important, delegate to other talented engineers. As the project grew, it attracted other talented engineers who were able to contribute to Linux, increasing the burgeoning project’s value and visibility and thus bootstrapping a virtuous cycle that continues to this day. Linux was first written to run on the Intel IA-32 architecture and was first ported to a Motorola processor. The porting process was difficult enough that Linus Torvalds decided to rethink the architecture so that it could be easily ported, creating a clean interface between the processordependent parts of the software and those that are architecture independent. This design decision paved the way for Linux to be ported to other processors. Linux is just a kernel, which by itself isn’t that useful. An embedded Linux system, or any Linux system for that matter, uses software from many other projects in order to provide a complete operating system. The Linux kernel is written largely in C (with some assembler) and uses the GNU tool set, such as make; the GCC compiler; programs that provide an interface to the kernel; and a host of others that you’ll encounter in this book. Much of this software already existed at Linux’s genesis, and, fortunately, much of it was written with portability in mind. The fact that this software could be used on an embedded system or could be modified to make it suitable for embedded deployment contributed greatly to the acceptance of Linux for devices other than desktop machines. This book takes you through using Linux for your embedded project. Because Linux and its associated projects are open source, you learn how to build everything you need for an embedded project from scratch. The entire Linux environment has advanced to the point that this undertaking is no longer a quixotic exercise; it falls squarely within the reach of any engineer willing to put in a reasonable amount of time and effort. Building a complete Linux system is the best training for creating a small Linux system; as a result, doing so is more than a morale-building exercise.