Unix Turns 40: the Past, Present and Future of a Revolutionary OS

Originally written in one month during the summer of '69, a little operating system called Unix would go on to be one of the most important pieces of software ever written. Four decades later, the future of Unix is clouded, but its legacy is certain.

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But a recent survey by Computerworld suggests that any migration away from Unix won't happen quickly. In the survey of 130 Unix users among 211 IT managers, 90% said their companies were "very or extremely reliant" on Unix. Slightly more than half said, "Unix is an essential platform for us and will remain so indefinitely," and just 12% said, "We expect to migrate away from Unix in the future." Cost savings, primarily via server consolidation, was cited as the number one reason for migrating away.

Weiss says the migration to commodity x86 processors will accelerate because of the hardware cost advantages. "Horizontal, scalable architectures; clustering; cloud computing; virtualization on x86 -- when you combine all those trends, the operating system of choice is around Linux and Windows," he says.

"For example," Weiss says, "in the recent Cisco announcement for its Unified Computing architecture, you have this networking, storage, compute and memory linkage in a fabric, and you don't need Unix. You can run Linux or Windows on x86. So, Intel is winning the war on behalf of Linux over Unix."

The Open Group, owner of the Single Unix Specification and certifier of Unix systems, concedes little to Linux and calls Unix the system of choice for "the high end of features, scalability and performance for mission-critical applications." Linux, it says, tends to be the standard for smaller, less critical applications.

AT&T's Korn is among those still bullish on Unix. Korn says a strength of Unix over the years, starting in 1973 with the addition of pipes, is that it can easily be broken into pieces and distributed. That will carry Unix forward, he says: "The [pipelining] philosophy works well in cloud computing, where you build small reusable pieces instead of one big monolithic application."

The Unix legacy

Regardless of the ultimate fate of Unix, the operating system born at Bell Labs 40 years ago has established a legacy likely to endure for decades more. It can claim parentage of a long list of popular software, including the Unix offerings of IBM, HP and Sun, Apple's Mac OS X and Linux. It has also influenced systems with few direct roots in Unix, such as Microsoft's Windows NT and the IBM and Microsoft versions of DOS.

Unix enabled a number of startup companies to succeed by giving them a low-cost platform to build on. It was a core building block for the Internet and is at the heart of telecommunications systems today. It spawned a number of important architectural ideas such as pipelining, and the Unix derivative Mach contributed enormously to scientific, distributed and multiprocessor computing.

The ACM may have said it best in its 1983 Turing award citation in honor of Thompson and Ritchie's Unix work: "The genius of the Unix system is its framework, which enables programmers to stand on the work of others."

Next: Timeline: 40 years of Unix

Gary Anthes is a former Computerworld national correspondent.

This story, "Unix Turns 40: the Past, Present and Future of a Revolutionary OS" was originally published by Computerworld.

Copyright © 2009 IDG Communications, Inc.

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