Although the first Linux kernel was created so that Linux Torvalds could have his home PC work like the UNIX operating systems he used at school, the latest 2.6 Linux kernel can stretch well outside the boundaries of the average PC.
The 2.6 kernel can now run on multiple computer architectures. It has also recently included significant improvements to allow it to run better on small, embedded Linux devices, as well as scale up to large, multiprocessor, high-throughput enterprise servers.
Today, you can find Linux running on all kinds of devices, from TIVO personal video recorders to hand-held computers. With improvements to the 2.6 kernel to support embedded systems, you can expect that trend to continue. The skills you learn with Linux today will help you work with all kinds of devices now and in the future.
Code from the uClinux project (www.uclinux.org) has been merged into the 2.6 kernel. The uClinux project ported the Linux kernel to run on microprocessors without a Memory Management Unit (MMU). Removing MMU allows uCLinux to run without the hardware overhead required for multitasking applications. uCLinux was first ported to the Motorola MC68328 microprocessor and run on a PalmPilot.
With the inclusion of the uClinux code, the 2.6 kernel becomes ready to be ported to run on many new, inexpensive specialty processors. Besides the Motorola m68k processors, the Linux 2.6 kernel will support the NEC v850 processor and Hitachi H8/300 series of processors. Other processors to which uClinux has been ported are listed on the uClinux Ports page (www.uclinux.org/ports).
The Fedora DVD that comes with this book is built to run on Pentium class and above PCs. Ports of the Linux 2.6 kernel, however, are available to run on many other different processor types. You can find ports of Linux to dozens of different computer architectures on the Ports of Linux page (http://perso.wanadoo.es/xose/linux/linux_ports.html).
While this trend to port Linux to many different architectures is expected to continue with the 2.6 kernel, a new subarchitecture feature of the 2.6 kernel adds a new dimension to possible future ports. The subarchitecture feature separates processor types and hardware types. This feature opens the possibility to support architectures such as the NCR Voyager architecture and PC-9800 architecture (both of which supported x86 processors on nonstandard hardware). The subarchitecture feature opens the gates for the 2.6 kernel to be ported to other computer hardware that uses industry standard Pentium-class processors with specialized hardware.
Although the Fedora Core 3 distribution included with this book runs on 32-bit Intel x86 architecture PCs, there is an AMD64 version of Fedora Core 3 available as well. You can download a copy of that distribution from http://fedora.redhat.com/download. Most of the software descriptions in this book will work with that distribution as well.