This offers IT departments the possibility of using Linux to consolidate resources into a single skill set, or at least a single OS.
The danger, however, is that since developers are free to conduct extensive customization, it may fork into a number of incompatible versions.
''The differences between the versions of Linux can increase the level of effort on the part of the system administrators as software installations and verification can vary from system to system,'' says Rob Pennington, CTO and head of the Innovative Systems Laboratory at the National Center for Supercomputing Applications. ''The different OS types and versions make it very time consuming to verify that all the pieces (libraries, compilers, file systems, etc.) work together as expected.''
Pennington has five Linux clusters under his control, including a 16 Teraflop Tungstun (W) cluster, which runs Red Hat Linux on 2560 Intel Xeon processors. Several of the clusters are part of the TeraGrid, a 40-gigabit-per-second network, linking computers at nine universities and national laboratories.
''A researcher should be able to use any of the systems without having to know the paths to all of the necessary tools, the methods to submit jobs for execution or the paths for the storage systems on the systems,'' he adds. ''This would appear to be simple but it becomes very complex when this same type of goal is applied to multiple sites, such as those within the TeraGrid.''
But the problem of Linux compatibility doesn't just affect those developing high-end research applications. Software vendors also are significantly impacted.
There are more than 380 different Linux distributions, after all, and developers need to make sure their products function well on at least all the major ones in order to make their efforts profitable.
''In the beginning, end users, application developers and system administrators were delighted to have the flexibility to make very personal corporate decisions,'' says William Hurley, senior analyst for Enterprise Strategy Group in Portland, Or. ''Though there is a lot of freedom in that, the ultimate long-term goal is to standardize on a class of technologies, not just within the organization, but on explicit or de facto industry standards so it is easier to apply complimentary technologies.''
The danger with Linux is not at the kernel. Although there are many independent developers contributing their labor, what gets released publicly is firmly under the control of Linus Torvalds.
''At the kernel itself, the community is very disciplined, so you don't see the kernel forking,'' says Bill Weinberg, an open source architecture specialist who works for the Open Source Development Laboratory (OSDL) in Beaverton, Or. ''But there is the potential for divergence among some of the Linux distributions, which makes it challenging for vendors to ship shrink-wrapped software without having a lot of installation and maintenance challenges across distributions.''
To make the job easier, several groups are creating standards and tools to ensure software interoperability. They include:
''The LSB offers data center managers a way to protect their data and application investment for the long term,'' says Free Standards Group executive director Jim Zemlin. ''If you don't want a vendor gun held to your head, invest in open standards based products.''
Unite or Die
It remains to be seen whether these standardization actions will work, but early indications are positive.
While commercial software vendors try to create features to differentiate their products, there are two factors limiting this in the open source community. One is that users feel a personal stake in the software and apply group pressure to keep everything open and interoperable. The other is the nature of the open source licensing which limits exclusive, proprietary code.
As long as these factors hold the Linux community in line, we can expect to see continued expansion of its functionality and installed base. If that doesn't work, the boys in Redmond are standing by ready to pick up the pieces.
''If Linux does begin to show a fractured face like Unix did, it will create an unintended opportunity for Microsoft,'' says Hurley. ''Microsoft has been aggressive in highlighting various studies showing a positive TCO for Windows compared to Linux, and this would be another front Microsoft will exploit to ensure placement of Windows.''