Moore's law famously states that the number of transistors in an IC will double (approximately) every two years (with an addendum that the cost would halve at pretty much the same rate). This law, which remained quite accurate for many years, is one of the things that clearly underscored what people came to realize, and even celebrate, about the electronics and the Information Technology (IT) industry; the sheer speed with which innovation and paradigm shifts in technology occur here is unparalleled. So much so that we now hardly raise an eyebrow when, every year, even every few months in some cases, new innovations and technology appear, challenge, and ultimately discard the old with little ceremony.

Against this backdrop of rapid all-consuming change, there lives an engaging anomaly: an OS whose essential design, philosophy, and architecture have changed hardly at all in close to five decades. Yes, we are referring to the venerable Unix operating system.

Organically emerging from a doomed project at AT&T's Bell Labs (Multics) in around 1969, Unix took the world by storm. Well, for a while at least.

But, you say, this is a book about Linux; why all this information about Unix? Simply because, at heart, Linux is the latest avatar of the venerable Unix OS. Linux is a Unix-like operating system (among several others). The code, by legal necessity, is unique; however, the design, philosophy, and architecture of Linux are pretty much identical to those of Unix.