In the dim days of 1970s, when a Digital PDP-11 was the state of the art in minicomputing for a mere $65,000, Unix was just taking its first baby steps at Bell Labs. Dennis Ritchie and Ken Thompson couldn't have dreamt that this attempt to produce an interactive timesharing system would someday become the lingua franca of server-based computing.

The early days of Unix at Bell are full of landmark events. The development of the C programming language. The concept and implementation of pipes. The first file system, inodes and all. It was also at this time, in 1976, that the University of California at Berkeley (UCB) began to participate in Unix development, culminating in the development of 4.2BSD. Meanwhile Bell continued to refine Unix, eventually releasing System 6 and System 7. It was on a Tandy 6000, running System 7 (technically Xenix), that I first really began to play with Unix.

In the 1980s, Unix began to be a real player in the computer industry. The 800-pound gorilla was, of course, the VMS operating system running on DEC's VAX minicomputers, but a small rebel company called Sun Microsystems was making headway selling a variant of Berkeley Unix they called SunOS (later Solaris). Also, companies such as HP and Apollo were offering systems running their own varieties of Unix. And Bell (now reconstituted as AT&T) was selling a System 5, running on platforms like the 3B2.

But for all its promise, Unix had problems. For one thing, there was little in the way of portability in programs. Binary compatibility was nonexistent, and even recompilation could be an adventure (anyone old enough to remember being asked if your machine was big-endian or little-endian?). And Unix could be as expensive as any of the other traditional operating systems.

Into the fray stepped Richard Stallman and the Free Software Foundation. Eagar to provide a not-for-profit version of the Unix operating system, they first needed to build the tools to build the tools, things like a C compiler and parser generator to replace the proprietary versions (we know these tools today as gcc and bison/yacc, among others). And while the FSF toiled away on their OS, a funny thing happened. People started noticing that the FSF versions of the Unix tools were often better than the commercial versions, and free! For example, Sun charged $10,000 for their C compiler, but gcc worked just as well. But as years dragged on with no OS in sight from the FSF, the commercial implementations continued to be the only game in town outside VMS and the upstart called Windows.

It would fall to an unassuming Scandinavian, not the FSF, to change the Unix world forever. No one reading this magazine needs to hear the story of how Linus Torvalds started working on an open source Unix kernel as a personal project, and ended up spawning the most widely adopted non-Microsoft operating system in the world. But it's worthwhile to note what made Linux so special. For one thing, it could run on low-cost Intel-based PCs, the same kind that people bought to run Windows. That meant you didn't need to spend a fortune on hardware if you didn't want to. Also, even across different hardware platforms (say an IBM 3090 and a Dell laptop), the source code remained compatible. And inside the same platform, even different vendor releases like Red Hat and SuSe could run each other's programs.

The other breakthrough was making it open source, which meant that the people most motivated to fix problems and add new features (the people encountering the bugs and needing the features) were empowered to do so. If you had a critical problem, you didn't need to wait for a vendor to decide it was important enough to fix. You could fix it yourself.

Today, Unix (both in proprietary implementations such as Solaris and open versions such as Linux and FreeBSD) is the 800-pound gorilla of the server market, big enough to make Microsoft scramble for market share in Europe, and big enough to make companies like SCO try to grab a piece of it. Truly, a long way from two Bell engineers scrounging for a computer to whip up a new operating system.

• Who Owns Unix?