IBM has ported Linux to its S/390 mainframe platform, but is keeping the news - which could send shockwaves throughout the industry - under wraps for now.

An attendee at a mainframe conference held earlier this autumn said that IBM, "talked about but did not announce Linux/390. The future technical session showed foils about Linux/390."

He said that there would be two versions. The first will be Linux/390 under virtual machine (VM) only, and the second will be Linux/390 on S/390, running "bare metal" - directly on the hardware itself.

According to this source, Linux/390 under VM is ready now and IBM had hoped to announce this at the conference, but the decision was delayed. He understood that "most software runs by just recompiling for Linux/390."

Phil Payne, an independent analyst, said that IBM is porting a Linux compiler to S/390 to alleviate delays porting applications such as SAP and Lotus Domino to the mainframe.

"It is a time to market issue. Domino and SAP are developed in C and designed for NT and Unix. By the time they hit the mainframe there is a severe time lag," he said.

"Putting a Linux environment into S/390 and having a standard compiler will decrease the delay. It will give the mainframe a tremendous competitive advantage," he added.

He said that IBM has considered Java on the mainframe, "but it is not quick enough." Mitul Mehta, European group manager for Frost & Sullivan said, "all the indications I've had are that IBM is trying to transport Linux onto S/390."

He added: "I believe it is already there, it is just a question of when they announce." Mehta believes that IBM will upgrade S/390 to take on Linux because it has to stay ahead of the game: "Large organisations are evaluating Linux and they can't afford to be late in the game. If customers say they need it, they must provide it."

Payne said that there are suggestions that Domino actually runs better on the mainframe than on smaller multiple engines and that "the affinity between Domino and larger processors" could even put the mainframe ahead of other operating systems if the time lag problem is solved through Linux.

A spokesperson from IBM said: "If customers need it we will respond. It is not our practice to speculate about what we will or will not do in the future."

She added: "We want to respond to customer needs and are constantly evaluating the market requirements."

In September IBM announced software it described as a Linux emulator. This provides an application program interface which allows Linux applications to be recompiled to run on IBM's own AIX variant of Unix.