Linux running on the B50,F50 enterprise servers and 43P Model 150 and 260 workgroups servers.
Linux on the mainframe IBM 370/390
Linux for S/390
a prototype port of Linux to the S/390 architecture. Linux for S/390 is a "pure" Linux from a user point of view. It supports the S/390 processor architecture and some devices that are specific to S/390 environments
Red Hat Linux for S/390
designed specifically for IBM's eServer zSeries family of S/390 mainframe computers, Red Hat Linux for S/390 allows you to create a highly reliable, secure, and portable infrastructure platform and cost effectively manage your mission-critical IT workloads
Slack/390 is port of Slackware Linux to IBM's S/390 hardware.
Think Blue Linux
a Linux distribution for S/390. S/390 is IBMs most reliable hardware platform