Believe it or not, this month marks 20 years since IBM made the smart choice of opening its proprietary computer technology and announcing it would support Linux on IBM Z, a family of z/Architecture mainframe computers from the Z900 series, which is now used by more than two-thirds of the Fortune 100 companies to protect their highly sensitive data. It was back in 1999 when the original IBM team in B??blingen brought the idea of Linux on the IBM mainframe to Linus Torvalds, porting the Linux kernel to the S/390 architecture, and then publishing the collection of patches and additions needed to enable Linux for IBM System/390.