Linux on the IBM ESA/390 Mainframe Architecture

Linux on the mainframe? 65535 attached devices, and all of them busy? Unlike the mythical beast Bigfoot, there is evidence that Linux on Big Iron exists. We want to believe. The truth is out there. Watch out for the penguins.

News Flash! Bigfoot is not alone! There are now two ports of the Linux kernel to the IBM S/390. The first port is documented in greater detail below. The second port was developed by IBM engineers living in a cave. Because they had no access to the outside world, this port is completely incompatible. However, market realities are such that the IBM effort is currently the defacto leader. That project is staffed by a number of paid, full-time developers, whereas this project was staffed by a small number of unpaid volunteers. That code is the focus of intensive ongoing development, test and deployment, while this project is in hibernation, with no active development going on at this time.

This may still change. There are still a few sticky points with the s390 port that probably aren't important, but could make thing ugly if not eventually resolved. These are:

If the above sounds like a critique of the s390 port, keep in mind that the s390 port is currently more technically advanced, and is the subject of active use and ongoing development. Note that the i370 port is stagnant.

The Bigfoot Port (aka i370)

This section describes and provides status for the original Linux/390 port.

Why do this?

Why do this? Its a question that comes up often enough, fairly, even I suppose, and so it deserves and answer. For the nookie, of course.


This project became defunct in 2000, after IBM's announcement of a competing project seemed to make it pointless to continue wiht this project. See the "why do this" page for the details. A big THANK YOU goes out to Melinda Varian of Princeton University for providing access to the Princeton IBM/370 mainframes to do this work!
Last updated February 2000 by Linas Vepstas (
Copyright (c) 1998,1999,2000 Linas Vepstas.
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