Unix operating systems are not updated as frequently as Windows and Linux OSes, and their end users like it that way.
IT pros who run IBM's AIX, Hewlett-Packard's HP-UX or Sun Microsystems Inc.'s Solaris say they're happy with the frequency of their OS uploads and fixes; they don't want to be in a perpetual state of updating or patching their operating systems, which often run mission-critical applications. HP, for example, recently released the newest of its semi-annual updates to HP-UX 11iv3, which debuted in 2007.
IBM's latest major release of AIX also came out in 2007, and the last major release of Sun Microsystems' Solaris came out in 2005. According to IDC analyst Al Gillen, commercial Linux and Windows operating systems, are updated more frequently than Unix
Every three years or so, Microsoft has a full new release of Windows Server, but the upgrade cycle is punctuated by several service pack releases of fixes and R2 feature roll-up releases that can be major. Early Linux proponents cited the fast pace of updates and patches as a major benefit for that open source operating system. Over time, though, business users balked and Red Hat Inc., for example, agreed to slow down to a more Unix-like pace.
"I think twice a year is about all I can handle," said Mike Gruen, the IT project manager for Bernalillo County, N.M. "I am doing all the Unix stuff myself, plus a bunch of other things. If we were to get a dedicated Unix administrator, I could see more frequent updates. The way it stands now, twice is all I can support."
The county recently moved from older PA-RISC-based HP servers to Itanium boxes, all running HP-UX. The government also recently migrated its juvenile detention center application from Windows to HP-UX. Gruen does security patches as they come out, and then big updates as HP provides them.
Fewer OS updates, less disruption
The infrequency of updates creates a more stable environment, Unix users say. Gillen added that much it is a matter of the OS's maturity as well.
"The frequency of Linux updates is going down some, and that reflects the maturing of Linux," he said. "But irrespective of how often the releases come out, if there is good support, customers will try to stick with a particular release as long as they can. They're going to try to extend the life expectancy as much as possible."
Gillen added that operating system providers try to release OS updates that cause as little disruption to applications as possible.
"They realize that creating updates that cause impact beyond the OS level is considered a concern by customers and is a blocker for adoption," he said. "If a vendor wants acceptance of a certain update, they need to keep it as nondisruptive as possible."
Paul Sikora, the vice president of IT transformation at the University of Pittsburgh Medical Center, which runs all flavors of Unix and Linux, says that IBM's strategy for AIX is to release an intermediary "technology levels" update every six months, and then have service packs and other security fixes in between. UPMC's strategy is to minimize major updates to once a year and then fill in the holes where needed.
"For the past two years, our modified service plan is apply a major OS release, its latest [technology level] and its latest [service pack] once a year," he said. "Everything in between is ad hoc. We review each fix, determine its importance to our environment, and decide if we will apply it."
If IT decides to apply a fix, they work with application owners to get it installed. If they delay, Sikora makes sure they are aware of the risk.
"I've been quite satisfied with this service plan," Sikora said. "It fits pretty well with our release schedule."
Unix market share continues to decline, mainly at the expense of Windows and Linux, according to recent IDC figures. In September the research firm reported that Unix revenue was below the $1 billion mark for the second consecutive quarter, with revenue down almost 40% annually.
But Unix still represents a multibillion-dollar market, which will take years to whittle down. Sikora said the university runs AIX and HP-UX for Oracle and other databases. He says those operating systems have good backup and clustering features and that Unix plays an important part in every one of the data center's enterprise servers.