You could hear a few murmurs of surprise at the recent Gartner Data Center Conference when more than 40 per cent of those responding to an audience participation poll said mainframes were part of their IT environments.

There were about 2,000 attendees at the Gartner-sponsored conference, and many were from large companies that continue to rely heavily on heterogeneous IT environments -- despite a push by many vendors toward industry-standard servers. In fact, when asked whether they run their environments on either Windows or Unix exclusively, only four per cent said yes.

Abdul Khan, who manages servers and storage for Blue Shield of California, said the San Francisco-based insurer relies on mainframe systems. "It's an integral part of our legacy systems," said Khan, whose mainframe environment supports custom-written applications that would be too difficult to move to other systems. "It would take a long time to change our software."

Khan also said he believes that mainframe systems continue to lead in terms of reliability.

Another mainframe advocate is Bill Homa, CIO at Hannaford Brothers, a $5 billion grocery retailer and one of the first companies to implement IBM’s new zSeries z9 mainframe.

Homa’s z9 was installed four weeks ago and is an upgrade from an earlier mainframe. It is one of the company's two IBM mainframes, part of an IT environment that includes 200 Unix AIX servers and about 250 Windows servers.

Homa’s mainframe environment runs custom-built applications that manage its supply chain. Employees can connect to it and its database via wireless devices, allowing them to immediately place product orders as they move through store aisles and warehouses.

The z9 can process one billion transactions per day, more than double the transaction processing capability of the zSeries z990, which Hannaford also uses. Homa said IBM also made architectural changes to the z9 that improve its ability to pull data from its database by about 30 per cent.

Rapid processing capability is critical to his wireless users, but what Homa likes about the z9 is its scalability; he’s using only two processors on a system that can support 64. “This machine is doing more work than [the] other 500 servers in the data centre put together,” he said.

Some users stay on mainframes because their custom-built applications are too difficult to move. But Homa is continuing with custom development by using India-based services provider Infosys Technologies. He said his software costs, including maintenance and development, are as much as 30 per cent less than what he would pay if he purchased a packaged application. “It’s very easy to do custom development of our applications -- easier than buying them," he said.

While users continue to run their own mixed environments, Gartner sees an ongoing and unabated push by vendors toward utility computing, where companies buy computing power and processing power as needed, with the underlying hardware becoming less important. But that trend is "a long way from reality for most of us today," said Gartner analyst Steve Prentice.

Vendors, for example, face a problem in delivering utility services because it threatens to undermine their own hardware sales. "As soon as you start competing with your distributors, you have deep problems," said Prentice, adding that most vendors "would rather sell you access to computing power than the hardware itself."

On a related note, Donna Scott, another Gartner analyst, said users will have to continue to push enterprise vendors toward standards that will improve that interoperability of heterogeneous environments.

Another issue users will have deal with is the ongoing introduction of "consumer grade" technology into their work environments. That includes applications such as America Online's instant messaging system, peer-to-peer voice technology from Skype and Google's desktop search tool.

In an instant conference poll, 20 per cent of the attendees said they have banned those technologies from their users' systems, while 43 per cent said they discourage them, and 26 per cent said they allow them to be used but don't support them. The rest either encourage their use and/or support them as well.

Prentice said the use of these consumer technologies is something IT workers will ultimately have to learn to live with, especially if they want to keep their environments attractive to knowledge workers. "You cannot stop consumer grade technology from entering the enterprise," he said.

Another trend Gartner sees continuing is a general decline in hardware costs as virtualisation technologies improve server utilisation and companies move to pool more of their assets and data.