The Linux Foundation announced April 8 its annual sponsorship of independent IDC predictions about how the Linux ecosystem will grow over time. The answer is "a lot" but exactly what you'd expect in relationship to the UNIX ecosystem.

I usually measure Linux/UNIX usage growth/decline by following the IDC quarterly view of server shipments. The clear trend from that perspective is that factory shipments of servers with Linux is increasing basically at the rate that factory shipments of servers with UNIX decreases. It gets the rabid open source blogosphere foaming at the mouth to say this but Linux is basically the latest version of UNIX. So market researchers expect the two operating systems to move in this manner.

From a market research perspective, looking at the Linux ecosystem separate from the UNIX ecosystem would be like looking at the growth of Windows 15 years ago without also watching the decline of DOS. Bascially,  you choose the IBM and HP versions of Linux et al for factory shipments if you used to choose AIX, HP/UX and so forth. In addition, leading server suppliers are partnering with Linux services suppliers such as Red Hat, Canonical and so forth for follow-ons. This is relatively low-margin services business the major systems suppliers used to take for themselves.

The IDC report released April 8 looks at the same trend from a different perspective. By the way and not coincidentally, the Linux Foundation is funded by platinum sponsors Fujitsu, Hitachi, HP, IBM, Intel, NEC, Novell and Oracle along with dozens of other Gold, Silver and Affiliate sponsors. Rather than measuring your choice of servers, the new IDC research predicts your "Linux-related software spending." The forecast says Linux-related software revenue will grow from $12 billion to $35 billion between 2008 and 2013 while "Unix spending" goes almost almost flat (from $69 billion to $74 billion). This statistic forecasts not only the Linux- and other open source operating software (e.g., Solaris) revenue flowing in the market but the revenue of license fees, maintenance and related subscriptions for application servers, ESBs, databases, ERP, BI and even consumer software running on those operating systems. Note that much of this software is not tied to open source terms and conditions (Ts&Cs). As an example, an Oracle database and SAP R/3 running on a Linux server would be considered Linux-related software spending in this case.

The IDC report also has some interesting information about cloud computing, virtualization and the effects on the market of the current economic downturn. It is available free from the Linux Foundation Web site. I wrote about a companion piece of IDC research sponsored by Novell here.

By comparison, "Windows-related" revenue, according to the same IDC white paper, will grow from $149 billion to $206 billion during the same period. That is, both ecosystems are growing at about the same compound annual growth rate of 6 percent to 7 percent. That's also as one would expect because both ecosystems are rapidly becoming the two dominant choices you have in the marketplace. As has been the trend for a few years, Linux- and other open source-based software is replacing UNIX-system-based software while Windows-based software is displacing OS/400 and other similar less IT-personnel-intensive systems.

As always, be careful of statistics. These statistics do not tell the whole story of the marketplace and your choices in it. For example, just as a lot of the software in the open source operating system ecosystem is deployed with traditional Ts&Cs (the Oracle/SAP example above), a lot of the software revenue measured in the Windows ecosystem is distributed with open source Ts&Cs. Examples are JBoss or MySQL running on Windows

(At this same event, a debate between Linux, Windows and Solaris devotees was planned. More to come in a future blog post.)