10th Anniversary of Linux for the Mainframe: Beginning to Today

2010 marks the 10th anniversary of Linux for the mainframe. Here, Knowledge Center contributor Bill Claybrook delves into the 10-year history of Linux for the mainframe, discussing its first deployments, advantages and appropriate workloads, as well as its current market outlook, cost of ownership and available applications. He also offers advice on how you can determine if Linux for the mainframe is the right choice for your data center's server virtualization project.


The year was 1999. It was the beginning of Linux for the mainframe. IBM and SUSE (which was later acquired by Novell in 2004) began working on a version of Linux for the mainframe. By 2000, the first enterprise-ready, fully supported version was available: SUSE Linux Enterprise Server for S/390. The first large, important customer was Telia, a Scandinavian telecommunications company. This year, 2010, is the 10th anniversary of Linux for the mainframe. The value propositions for Linux for the mainframe that were important in 2000 are still important today.

Linux for the mainframe began as two separate projects to port Linux to IBM mainframes. The first effort, the Bigfoot (i370) port, was initiated by Linas Vepstas in August 1998. Vepstas and his coworkers used IBM/370 mainframes at Princeton to do the port. A brief history of the Bigfoot project can be found here and here. The Bigfoot port became stagnant for political, social and market reasons after IBM announced the second port of Linux to mainframes (the Linux for S/390 port).

The Linux for S/390 port started in 1998 as a skunk works project at the IBM Boeblingen Lab in Germany, but IBM kept the Linux for S/390 port secret for more than a year. Speculation has it that secrecy was the order of the day because the developers feared political opposition from other parts of IBM. As a result, the S/390 team chose not to work with the Bigfoot team. The S/390 project was publicly announced on December 18, 1999. It was based on the 2.2.13 Linux kernel.

The first commercially available Linux for S/390 came from SUSE in Germany. SUSE began working with IBM, primarily at IBM Boeblingen Lab in Germany and Marist College in 1999. The Boeblingen Lab is only about a two-hour drive from SUSE's headquarters in Nuremberg. This explains the reason for SUSE's close relationship with IBM on the Linux for S/390 porting project. At the time of the Linux for S/390 port, SUSE had a number of different ports for Linux in-house, including ports for PowerPC, x86, Alpha, and SPARC.

In the 1999-2000 time frame, when SUSE was busy getting Linux up and running on IBM mainframes, there was no pressure (and no priority) to get involved with other mainframe vendors. Linux for the mainframe involved creating new processes and infrastructure at SUSE, a new business model, need for 24/7 worldwide support, synchronized IBM/SUSE Level 3 support processes, and ISV and IHV certification, etc. Interest by Fujitsu and Hitachi was more on the x86 and IA-64 (Itanium) platforms, even though their mainframes were compatible with IBM mainframes. Early versions of SUSE Linux Enterprise Server for S/390 ran on both Amdahl and Comparex machines, but the vast majority of mainframe customers in 2000 used IBM mainframes-and this is also the case today.

In order to get SUSE Linux Enterprise Server up and running on the S/390 mainframe, Marcus Kraft (the SUSE development manager for the port at the time) said that SUSE needed a compiler, library, and some base packages. The SUSE engineering team got most of this from Marist College in Poughkeepsie, NY. With the work that Marist College had done, the SUSE engineering team was able to get SUSE Linux Enterprise Server up and running on the S/390.

The next step was to gain access to a mainframe to continue the development and testing necessary to make the port of SUSE Linux Enterprise Server into a viable commercial product. SUSE got access to a machine from IBM and, with the aid of the SUSE Autobuild system, the company was able to get a system that worked up and running in about a week.

IBM had some legal problems around software drivers for Linux for S/390 because of the Intellectual Property (IP) in the drivers. As a result, the first version of SUSE Linux Enterprise Server for mainframes had object code-only drivers provided by IBM. Since then the IP problem has been resolved, and now all code is upstream and publicly available under the General Public License (GPL).

To get potential customers interested in Linux for the mainframe (in 2000, Linux on x86 was in its infancy) before the official release of SUSE Linux Enterprise Server for S/390, IBM and SUSE held a two-week-long install party. Because participants could not bring mainframes to the facility where the install party was being held, conference calls were used to walk interested companies through the installation steps. Many of the customers that participated in the initial install party are still loyal SUSE customers today.