If you look inside a modern data center, you’d be hard pressed to find Unix machines. Mainframes and the like have been losing a long battle against commodity x86 hardware, and Unix distributions, once plentiful and widespread, have dwindled along with their big-iron homes. While Linux has undeniably usurped all forms of Unix as the default operating system for enterprise data centers, that doesn’t mean there aren’t still areas where the venerable dinosaur of operating systems rises above.

When it comes to maximum availability, superior partitioning and extreme CPU throughput, Unix remains the go-to OS for many large organizations, from businesses to schools to governments. And the popularity of Unix variants does not end with IBM, HP and Oracle: Apple is, perhaps, the largest distributor of Unix in the world, with millions of iPhones that run a BSD kernel in use around the globe.

Open Source Initiative cofounder Bruce Perens said that, thanks to Apple, Unix is more popular than ever. “We now have more Unix systems than we’ve ever had before. They are in our phones and our access points. I think if you actually set out to count, you could make a graph and show that Unix—if you define Unix as something that serves a POSIX I/O—that Unix is at its peak today,” he said.

“What’s the difference? We don’t care about the stuff the user doesn’t see. The user doesn’t see Unix. This is something I often have a hard time explaining to companies.”

And while one of the world’s largest companies—Apple—is based entirely on Unix kernels, that doesn’t mean Unix is on the cusp of a massive comeback. In fact, it would seem that the formal Unix market has essentially stood still in recent years.

Steve Sibley, director of Power Systems management at IBM, said that Unix as a business product is alive and well. “If you look at both Gartner and IDC data that came out in 2011, we not only grew, but grew faster than the market,” he said.

“The demise of Unix has been overstated, in part because of some of the challenges the competitors have seen. We continue to see growth, as more and more clients either migrate to AIX or other technologies, or migrate up to Unix qualities of service from Windows and Linux.”

Sibley said that the traditional strengths of Unix are still present today. “Most of our high-value data is probably on Unix or mainframes, more than any other place,” he said.

“From a security standpoint, Unix has been a harder target. There are a lot less vulnerabilities, and I think part of that is the ubiquity of those other platforms. But it’s also some of the inherent security capabilities of Unix. We were more careful to address those early on, where Windows was more focused on the graphical interface than covering up access points for hackers. We have a lot of focus on security.”

Indeed, security is a huge benefit of Unix, even without the partitioning and extra security layers enterprise Unix offerings include. Because Unix variants are less populated on the Internet, hackers don’t necessarily know how to use these operating systems, much less exploit them. In fact, this has been a benefit of many Unix variants for years. In the 1980s, hackers largely divided along operating-system lines, aligning themselves with their favorite platform to attack. That platform could have been AIX, VMS, AT&T Unix, or any of a half-dozen other varieties, each with its own file locations and commands.

With such a thick layer of variability on top, the popularity of Unix ensured a vibrant and varied ecosystem. But in the 1990s, Linux began to gain market share. Of course, the 1990s were also when the various BSD Unix distributions began to come into their own as well. With the combined appeal of x86-based Linux, FreeBSD, NetBSD and OpenBSD, the market began to move toward commodity hardware and away from the expensive big-iron mainframes that had traditionally been the home of multi-user operating systems.
Rising Sun
While the various BSDs remain in use, it is Linux that has clearly dominated the former Unix market. With Red Hat now earning over US$1 billion in revenue, the days of the dedicated Unix company are over. That’s why the major Unix vendors are either considering or actively distributing x86 alternatives.

HP announced last year that it is beginning to move its HP-UX-focused offerings onto x86. Oracle’s Solaris operating system has been available in an x86 variant for years now. Indeed, only IBM has yet to offer its Power series AIX-based systems in an x86 variant.

Kate O’Neill, director of product marketing for HP’s Business Critical Systems division, said that her customers are eager to move to x86 systems in their high-availability environments. “We’re also seeing a growth in customers looking for mission critical in more of an x86 Windows or Linux environment. Our Project Odyssey announcement is about our strategy to continue to deliver on those traditional capabilities, but also looking at our investment in bringing mission critical x86 to reality,” she said.

Project Odyssey is the name of HP’s new effort to bring its Unix product line capabilities into its x86 line. The overall goal, said O’Neill, is to trickle-down the highly available capabilities of HP-UX into HP’s Linux and Windows systems management tools. She said customers have responded enthusiastically to the announcement of Project Odyssey.

Despite that enthusiasm, O’Neill said that most of the customers that are considering HP-UX are already Unix customers. “We do see growth within customers who are already comfortable with Unix and HP-UX. There continues to be a healthy and core set of customers that recognize the mission-critical needs they have to do,” she said.

That’s a sentiment echoed by IBM’s Sibley, who said that while the Unix market itself isn’t growing much, IBM has been drawing customers away from Solaris and HP-UX. Indeed, IDC and Gartner seem to show this is true: A 2011 report from IDC shows IBM has almost 50% of the overall Unix market share today, which has been growing since 2008.

Even Oracle admitted this is likely true—for 2010 and 2011. Markus Flierl, vice president of Solaris development at Oracle, said, “I think that was probably true two years ago, when we were going through the acquisition and it was not quite clear what we were doing. We’ve just gone through an entire refresh of our product line, and I think at this point if I were IBM, I’d be worried. We’ll see what the next year is going to bring,” he said.

IBM conceded that the technology in Solaris is competitive. Said Sibley, “We thought Solaris 11 was a pretty major upgrade. But certainly we think we’re growing in share around what clients’ investment in Unix is,” he said.

“Our view is we’re the leader in that environment. We also think in our view Unix and Linux are at least cousins, if not in the same family. So there’s still a lot of people, from a skill and capability standpoint, out there who are essentially using Linux in their business. So Unix in and of itself is down to those three, and HP-UX is struggling with their support from key ISVs. With Solaris though, Oracle is trying to make a renewed push with the Sparc processor.”

Charlie Boyle, director of Solaris marketing at Oracle, said that IBM’s claims of Unix dominance are now in the past. “I think IBM is drumming up old and past things. We’re seeing new customer opportunities on Solaris,” he said.

“We’re seeing them pick it over IBM and Power. IBM’s statement could have been true a year or two years ago, but we are taking share. I think one of the more important things we don’t see in this market is us trading share back and forth. We’re seeing new customers deploying Solaris now. They’re picking Solaris on the new T4 systems.”
No matter who is winning the battle for hearts and minds, there’s no denying that all of the Unix platforms continue to evolve and include new, powerful features. One of the primary things that draws developers and IT staff to Unix is the partitioning capabilities, and all three Unix platforms are strengthening those capabilities and the virtualization tools that support them.

Solaris’ Zones have long been an influential take on partitioning. Flierl said that future versions of Solaris will bolster this capability. “We’re working on additional optimization in the virtualization space. One of the things we are doing, we’re talking about network virtualization. We’re expanding that out into the network. If you migrate one of your zones over to another host, the network configuration will travel with it. You can create virtual NICs, and they can have bandwidth limits and security properties,” he said.

The next version of Solaris will also expand its memory capacity, said Flierl. He said that the goal is to enable support for up to 64TB of RAM on Solaris systems. “If you go up to those memory sizes, if you want to have one OS instance of Solaris running, it becomes critical to allocate the pages efficiently and think about things like the backplane of the system and the problems you’ll have if multiple people access the same chunk of memory at the same time,” he said.

HP is also expanding the capabilities of its version of Unix. “We’re making Service Guard available on a wider range of storage devices,” said O’Neill. That data integrity service will now be available on HP’s more modestly priced storage devices, bringing highly available storage capabilities to the mid-tier of businesses.

“Service Guard will be available with EnterpriseDB solutions, extending where Service Guard plays across the full spectrum of storage and database solutions,” she said.

HP is also bringing its vPars virtual partitioning software to lower-end systems. O’Neill said that vPars had previously been available only on HP’s massive Superdome systems, which are its top-of-the-line mainframes. As of April 11, vPars and its capabilities became available on smaller systems as well.

“The other thing we’re doing within our vPars is we’ve increased the access to storage by about seven times compared to previous capabilities,” said O’Neill. “Another key area we’ve improved upon is around the sharing of I/O across partitions, such that we’ve reduced the cost of I/O by 50%.”

The future of Unix for IBM looks to be focused on packing as many virtual machines as possible onto big-iron systems. “People are starting to deploy cloud-based services with AIX,” said Sibley. “We have managed service providers managing externally, but they’re moving into this multi-tenancy type of cloud as well. They have these public cloud views people are running, or people are launching quick services to send spam, then more complex services. Oftentimes today, that is single tenancy, but they’re looking at ‘How do I get more efficiency?’ ”

He added that “a cloud in essence is a highly virtualized environment that allows you to begin to enable clients and self service; to begin to launch new services quickly and easily, then be able to manage and budget your resources appropriately enough. We have a lot of clients that are doing that, and we introduced a smart cloud entry, which gives them that next step up. It includes virtualization, virtualization management through virtual machine control, and gives you the ability to move resources around. Beyond that, you get into some of the things Tivoli provides, which are more advanced functions of billing and orchestration. Then, obviously there are other third-party offerings as well,” said Sibley.

He said that future work on AIX will expand the capabilities of the operating system in cloud environments. “We’re also making sure we’re aligning and optimizing AIX into those environments as well. We’ll continue to make sure it can scale and handle analytic workloads, and that the Power processor can handle up to 1,000 threads on a single AIX image, as well as being able to put smaller and smaller images on smaller and smaller cores,” he said.

“We continue to reduce the number of updates that need to occur by bringing the system down. We have the best record for availability and uptime across all the other platforms except for System z. The goal is being able to have a system you never have to take down. We’re looking at other ways to do things so the applications never have to come down. We have the ability to move workload partitions on top of AIX between workload partitions.”

With all this focus on partitioning, multi-tenancy and virtualization, it’s surprising Unix isn’t more popular than it is. In a world where clouds can never be down, applications can never slow down and developers are building new software daily, it’s hard to believe that Unix on the server remains a small market, while Unix on the mobile device has taken over the world.