I think we all know which of the three major Unix variants has the largest number of paid up licenses for non embedded use: it's the one we usually hear least about, the Darwin BSD variant used by Apple to host the MacOS X shell.
There's equally little doubt about which Unix generates the largest number of web headlines and has the highest number of vociferous, web literate, supporters: that's Linux.
There's no doubt, furthermore, about which one offers the highest reliability coupled with the widest range of proven capabilities: that's Solaris.
But which one is growing fastest?
The answer is that we simply don't know. There are two main reasons, one obvious, the other rather subtle in the way it works out. The obvious problem is that some portion, and probably a majority portion at that, of Linux installs simply don't show up in anybody's hardware or license sales columns and are therefore impossible to count accurately.
The corolary problem is that the OpenSolaris community is quite young relative to Linux and that growth rates in downloads cannot, therefore, be fairly compared - and there's no evidence either way for the assumption that more Linux downloads go to mere tire kickers than do Solaris downloads.
More subtly, however, the factor that most distorts the picture is Sun's change from the traditional single thread CPU to the CMT/SMP line because the potential there, combined with the freedom offered by the CDDL license, has been driving developer decisions to experiment with Solaris. That's too small a number of licensees to blip anyone's counters, but with virtually everybody outside the most committed Microsoft and IBM shops now doing at least some work with Solaris, the possibility exists that an external event could trigger a landslide in formal commitments to the technology - and if the T2 release isn't quite it, Rock's impact on HP's remaining Itanium developers will be.
TImothy Prickett Morgan at itjungle has been tracking some of the issues here since Sun's original Solaris 10 Beta releases. Here's part of something he said about this during a July 30th comment on Sun's recent financial statements:
While Sun did not say so, the transition of Solaris 10 to a licensed product that comes in on the product side of the Sun product revenue sheet to a free product that Sun hopes customers pay to support, much as enterprises do for Linux and other open source programs, may be affecting the revenue shift. Sun has been tight-lipped about what the conversion rate for Solaris shipments to Solaris paid support contracts is, but if the number was high, you can bet Sun would say something. That said, with nearly 9 million licenses now distributed in two and a half years, even a fairly small conversion rate can generate hundreds of million of dollars. And Sun can allocate revenues on its Sparc-based servers, which have Solaris bundled on them, as it sees fit.
Jonathan Schwartz, Sun's president and chief executive officer, highlighted the fast-growing segments of Sun's product line, but the somewhat sparse details on what was selling in the quarter was equally telling. Schwartz singled out the Sparc T1-based "Niagara" server line, which accounted for $200 million in sales in the fourth quarter and which grew by 225 percent in fiscal 2007, breaking $550 million in sales, for particular acclaim. Sun's "Thumper" storage servers, which cram 48 SATA disks on a two-socket Opteron server running Solaris 10 and the ZFS file system, was also singled out, and Schwartz said that this machine, also known as the "Galaxy" X4500 server, has attained an annual run rate of $100 million. Sun's new blade server line is at a run rate of $55 million annually now, and the Netra telecom server line, based on both Sparc chips and Opterons, had 38 percent revenue growth in the fiscal year. In total, Sun's X64-based Galaxy server line (including Thumper arrays, presumably) showed 39 percent revenue growth.
What this says is that Sun's making money on services and non traditional sales: thumpers and the CMT/SMP line. If so, the liklihood exists that we'll get an "asperagus" (think "dam bursting") software surge for Solaris as all those developers now experimenting with Solaris certify their products for CMT/SMP - and drive Solaris to first place in the "fastest growing Unix" competition.