To keep LFS small and focused, the book Beyond Linux From Scratch (BLFS) was created which presents instructions on how to further develop the basic Linux system that was created in LFS. It introduces and guides the reader through additions to the system including networking, X, sound, printer and scanner support. Current Stable release of Beyond Linux From Scratch is 6.3 and was released on August 28 2007. This book follows-up on Linux From Scratch 6.2.
In addition to LFS and BLFS books Cross Linux from Scratch describes cross compiling and Hardened Linux From Scratch focuses on security enhancements like use of Stack-smashing protection, PaX and Address space layout randomization using grsecurity. Cross Linux from Scratch provides the necessary instructions to build a base, command line only Linux distribution. While LFS is limited to the x86 architecture, CLFS supports a broader range of processors. CLFS addresses advanced techniques not included in the LFS book such as cross-build toolchains, multilibrary support (32 & 64-bit libraries side-by-side), and alternative hardware architectures such as x86-64, Itanium, SPARC, MIPS, and DEC Alpha. Hardened Linux From Scratch is an extension of the focuses on creating a more secure version of the original Linux From Scratch as its main purpose, including embedded systems.
Linux From Scratch is a way to install a working Linux system by building all components of it manually. This is, naturally, a longer process than installing a pre-compiled Linux distribution. According to the Linux From Scratch website, the advantages to this method are a compact, flexible and secure system and the process leads to a greater understanding of the internal workings of the Linux OS.
As of Linux from Scratch version 6.3, the first package built by the user is GNU binutils. When building it, users are encouraged to time that build process using shell constructs and dub that time that system's "standard build unit". Once this number is known, an estimate of the time required to build later packages is expressed relative to the known SBU.
Several packages built during compilation take much longer to build than binutils, including the GNU C library (rated at 9.5 SBUs). The unit is not a concrete description, and must be interpreted as an approximation; many various and unrelated factors influence the wall-clock time that a package requires to build.