You are going to build the LFS system by using a previously installed Linux distribution such as Debian, Mandrake, Red Hat, etc. The existing Linux system will be used as a starting point, because you will need tools like a compiler, linker, text editor, and other development tools to build the system. Ordinarily, the required tools are available by default if you selected "development" as one of your installation options when you installed your Linux distribution. After you have downloaded the packages that make up an LFS system, you will create a new Linux native partition and filesystem. Here is where the LFS system will be compiled and installed onto. The next step, Chapter 5, will discuss the installation of a number of packages that will form the basic development suite which is used to build the actual system. Some of these packages are needed to resolve circular dependencies. For example, to compile a compiler you need a compiler. The first thing that will be done in Chapter 5 is building the toolchain, which is made up of Binutils, GCC and Glibc. The programs from these packages will be linked statically in order for them to be independant of the host system. When the first toolchain is built, you will rebuild those three packages again, this time using the toolchain we just built, rather than the host system's toolchain. In particular, all programs will be linked against the new Glibc rather than the host system's Glibc. All subsequent packages in Chapter 5 will be built and linked using this second toolchain installation. When this is done (building the second toolchain), the LFS installation process will no longer depend on the host distribution, with the exception of the running kernel. In Chapter 6 the real LFS system will be built. The chroot (change root) program is used to enter a virtual environment and start a new shell whose root directory will be set to the LFS partition. This is very similar to rebooting and instructing the kernel to mount the LFS partition as the root partition. The reason that you don't actually reboot, but instead chroot, is that creating a bootable system requires additional work which isn't necessary. As well, chrooting allows you to continue using the host while LFS is being built. While software is being installed you can simply switch to a different VC (Virtual Console) or X desktop and continue using the computer as you normally would. When all the software from Chapter 6 is installed, the temporary tools built in Chapter 5 will be removed. Chapters 7, 8 and 9 will finalize the installation. The bootscripts are setup in Chapter 7, the kernel and boot loader are setup in Chapter 8 and Chapter 9 has some pointers to help you after you finish with the book. Then, finally, you reboot the system into the new LFS system. This is the process in a nutshell. Detailed information on the steps you will take are discussed in the chapters and package descriptions as you progress through them. If something isn't completely clear now, don't worry, everything will fall into place soon. Please read Chapter 2 carefully as it explains a few important things you should be aware of before you begin to work through Chapters 5 and beyond.