For IBM, it seems like a return to the 1980s. After recording its first mainframe revenue increase in a decade in 2001, the company says that demand for mainframe power has continued to rise during 2002 – by 4%, at a time when server sales are falling.

Demand has been boosted by the launch of IBM’s new z800, a low-cost machine (by mainframe standards) that sold more than 200 units in the two months following its March 2002 debut. In addition, users are warming to the idea of running

Linux on their prized mainframe computers, says Rich Lechner, vice president of sales and marketing for enterprise servers at IBM.

But if that message seems positive, the reality is more mixed.

Lechner claims that there are three main new areas of growth for the IBM mainframe. First, as a server consolidation platform: Lechner claims that a combination of mainframe Linux and z/VM – software that enables a mainframe to run multiple instances of an operating system – can cost-effectively replace server farms of thousands of low-end Microsoft Windows NT/2000 machines.

Second, as an ebusiness platform: “Web applications are becoming more transactional in nature and the mainframe was designed from day one to be a transaction server,” says Lechner. And Linux adds a number of popular web technologies, such as the Apache web server, that can be run alongside these transaction-oriented applications on a Linux partition, he adds.

Finally, says Lechner, the zSeries mainframe is serving as the foundation for a number of roll-outs of major enterprise applications from vendors such as SAP and Siebel. “Seventy per cent of our capacity is [sold to support] these [three] new workloads,” concludes Lechner.

First time mainframe users include telecommunications company Deutsche Telekom’s T-Com unit. In July 2002 announced plans to migrate its systems from 25 Sun Microsystems Unix servers to a single zSeries mainframe running Linux to handle email, intranet and mail back-up services for both internal and external customers.

This sort of project is typical of new mainframe roll-outs. IBM would like prospective customers to believe that major organisations, like Deutsche Telekom, are seriously evaluating the mainframe for roll-outs of ebusiness and enterprise applications. But most new installations involve little more than consolidations of mundane functions, such as file and print, web and email serving. Consolidating anything more complex would be too time consuming and costly.

Furthermore, few users have rolled out SAP on the zSeries mainframe since it was launched in March 2001, according to Michael Tiemann, chief technical officer of open source software vendor Red Hat.

The main purpose of running Linux on the mainframe, says Tiemann, is to enable users to more effectively utilise spare mainframe capacity. In most cases, the mainframe is simply too expensive, both for server consolidation initiatives and for running most enterprise applications, even after the introduction of the $250,000 z800, he adds.

Tiemann’s views are partly coloured by the relationship that Red Hat has with IBM. Red Hat is one of only two vendors that supplies and supports mainframe Linux, but until recently IBM has favoured the distribution from Red Hat’s principal competitor SuSE. “They have leant almost drunkenly in that direction,” says Tiemann. In September, though, IBM bolstered its commitment to Red Hat, saying it would support the Linux version on its eServer zSeries, iSeries and pSeries servers, while also porting its DB2, Tivoli, Lotus and WebSphere software to Red Hat.

The alternative consolidation platform touted by Tiemann and analysts such as the Meta Group is the commodity Intel-based blade server. This is the computing model Lehman Brothers adopted when it was faced with the task of re-building two data centres destroyed in the terrorist attacks on the World Trade Center in 2001.

Previously, when Lehman’s IT department scoped out a project, staff identified a server that they believed more than powerful enough for the purpose, and bought two of them – to support replication and failover from one to the other if anything went wrong.

Now, Lehman runs a small number of blade servers and simply slots in extra blades when it requires more capacity. The manageability software built in to the blade server handles functions such as failover and load balancing. Furthermore, Lehman has made a big saving on the $40 million it received from the insurance company to replace hardware.

According to Meta analysts, the blade server will quickly put paid to IBM’s mainframe resurgence as suppliers improve its manageability and security capabilities. “[From 2005], we believe the Linux centre of gravity will inexorably migrate to the compelling economics and mainframe-class management capabilities of Intel-based blade servers,” they conclude.

Indeed, there is a more plausible reason for IBM’s modest mainframe resurgence: The withdrawal of Amdahl and Hitachi, its two biggest competitors, from the market in 2000, and the 25% price hike IBM pushed through shortly afterwards. If IBM’s claimed resurgence is, in fact, driven by these factors, it is unlikely to be sustainable for long.