IBM puts Linux on its mainframes

Hardware giant IBM is set to throw its weight behind Linux by debuting the open source operating system on its S/390 mainframes.

The move will allow mainframe owners to use applications written for Linux, without having to wait for them to be ported to the S/390 OS. It will also allow Linux servers, which are popular as web servers, to be connected to S/390 mainframes.

Doug Neilson, a consultant at IBM, said: "The beauty of Linux is that it achieves what Unix never did - the write once, run anywhere quality that allows applications to be used on any Linux platform."

Big Blue is targeting the technology at ISPs, ASPs and telcos, and said it could be used to replace whole server farms.

Multiple copies of Linux can run side by side on a mainframe using the S/390's virtual machine architecture. Each virtual machine acts as a separate Linux system configured for a specific task, such as generating web traffic or acting as a file server.

"We had one user running 41,000 copies of Linux on the same S/390 CPU. That's a bit over the top, but in practice large customers might run a couple of hundred. It would be an easy way to separate customer accounts," said Nielson.

Mark Lillycrop, research analyst at Xephon, said: "What's interesting is how it will be sold. If it is distributed free of charge, I don't think it will be top of the pile with IBM salespeople. But if a customer asks for it, at least they have that option."

The software is available to download for free, but it will also be distributed by Suse and TurboLinux for a charge. IBM plans to offer services and support for Linux in partnership with the two Linux vendors. There have been 2,100 downloads of the code since it was made available in January of this year.