Once upon a time, it was possible to dismiss Linux distributions as Unix knockoffs for undergraduate slackers who might someday be allowed on the real hardware if they behaved themselves.
That's no longer the case, as businesses small and large are learning that the combination of a free -- or nearly so -- operating system and commodity hardware present a compelling alternative to existing server platforms, particularly NetWare, Windows NT, and Windows 2000, while also threatening the position of the Unix variants from Hewlett-Packard, IBM, and Sun Microsystems. Although BSD-based open-source OSes were around long before a certain Finn became a media darling, clearly the momentum is behind Linux.
International Data Corporation (IDC) reported in September that new licences for Linux represented more than a quarter (27%) of server OS shipments in 2000. Windows took home 41% of the pie and NetWare and the major Unix variants split the remainder with 13.8% and 13.9%, respectively. BSD variants apparently contribute to the 4.3% share for "other" server OSes.
Given the newfound love for Linux among mainstream Unix vendors, the real future lies in the dogfight between Windows in one corner and the combination of Linux and Unix (which combined for 40.9% in the IDC report) in the other. Few customers are likely to adopt an either-or strategy, but it's clear which way the lines are going to be drawn for the next few years.
Explaining how Linux got this far takes some doing. Cost has a lot to do with it, of course -- many Linux distributions are free or almost so. Even the big-ticket versions designed for midrange and mainframe platforms might set back a budget by only a few thousand dollars.
Furthermore, the relative ease of porting code between Linux boxes and larger enterprise Unix systems has made Linux a popular development platform, if one that still gets knocked for its inability to scale to bigger systems with hundreds of CPUs and terabytes of RAM. But that situation is improving quickly: A year ago, Linux was unworthy for the enterprise because it lacked a decent journaling file system. Today, you have to look hard to find a Linux distribution that lacks one.
Linux distributions are still years away from catching up with more traditional Unix offerings in terms of raw scalability. Nevertheless, vendors such as IBM and Sun are already shaping their products to look and feel more like Linux, recognizing that if they want to be leaders, they'd better be out in front of the crowd. In particular, IBM is pushing "Linux affinity" in its AIX 5L as a major selling point for shops that want to keep development costs low by using inexpensive hardware to build applications that can be easily ported to more capable boxes.
But by the time the big players reach that Nirvana of seamless integration between Linux and their own interpretations of Unix, Linux may well have caught up on the scalability front, given the availability of increasingly capable Intel-based hardware. If you need to run a 32-CPU Linux box today, the hardware is out there and the software is almost there. Although that's still a long way from running 128 or 256 processors, it's clear that the gap between Linux distributions and traditional Unix offerings is narrowing quickly.
Major Linux publishers such as Caldera Systems, Red Hat, and SuSE Linux are reaching out to the corporate customer, although much of the hoopla surrounding the latest revisions of their distributions focuses on decidedly nonenterprise features, such as improved gaming support. But the vendors' enterprise act is coming together, and not too soon.
For example, Linux has a reputation for being unable to take advantage of the latest SMP (symmetric multiprocessing) servers supporting 16 or 32 CPUs. Today, that's generally a nonissue, even though some vendors are waffling by not supporting systems with more than eight processors. It's true that you can do a lot with an eight-way server, but the missing kernel support for additional processors is still frustrating customers that need to scale out by adding more processors instead of scaling up by putting more memory in the box.
Linux vendors are also scrambling to support the next generation of Intel hardware, Itanium-based 64-bit servers. Turbolinux is shipping already, and MandrakeSoft is at the release-candidate level, which means final code should be available by year's end at the latest.
Perhaps the more easily achieved challenge for Linux scalability lies in making the jump to more capable mainframe hardware. For example, Red Hat is adding support for the IBM S/390 (aka zSeries mainframe), whereas SuSE is already shipping its Linux Enterprise Server for S/390 systems and a Developer's Edition for iSeries (ex-AS/400) boxes. Turbolinux Server supports iSeries and pSeries (ex-RS/6000) servers, as well as the S/390.
An important issue for customers considering Linux is application support. Linux publishers are eagerly courting application vendors and ASPs, and major applications such as IBM's DB2, Oracle's 8i and 9i, and SAP's mySAP.com are certified to run on one or more Linux platforms.
Meanwhile, ERP and other line-of-business vendors are figuring that their offerings don't sound so costly when the customer thinks "Linux equals cheap."
Momentum is behind Linux. Even vendors such as IBM are recognizing the trend. And customers have already spoken: They want Linux and they'll run anything they can on it. It's up to Linus and friends to deliver the goods.
PJ Connolly covers OSes and security for the InfoWorld US Test Centre.