Linux S390 allows companies that have a mainframe to apply its reliability, massive storage capacity and unmatched I/O power to their e-commerce efforts. Further, since IBM offers their DB2 databse for Linux, e-commerce applications running on the mainframe have direct, high speed access to inventory, pricing or any other data the company uses the mainframe to manage.

IBM fully endorses the S390 version of Linux and participated in it's development.

Over 1,100 copies of Linux for S390 had been downloaded by mid April, and customers are asking IBM for enterprise level support for running Linux on their heavy hardware. Since you have to have a mainframe to run Linux 390, and only large corporations have mainframes, that indicates considerable interest in Linux among large corporations.

Linux is installed in a hardare partition on the S390, from which it has access to basic infrastructure services the S390 offers to software running on it. Since the mainframe already supports TCP/IP, Linux has ready to run Internet connectivity.

Linux is also been a boon to IBM's OS/2 customers (many of whom also have mainframes) because Linux programs are very easily ported to OS/2, expanding OS/2 software availability.

With Linux running on old 386s, Internet appliances, Alpha clusters that match supercomputer performance, and now top-of-the-line mainframes, Microsoft's already suspect "scalability" claims for Windows NT/2000 look downright silly.