A Decade of Development: The Open Mainframe Project and the Open Source Revolution
Founding members Steven Dickens, Len Santalucia and John Mertic reflect on the democratization of the mainframe ecosystem
Work was pretty busy in August 2015 for Steven Dickens, then a Linux product manager for IBM. He had been tasked with helping introduce the powerful LinuxONE servers to the marketplace, while at the same time helping the Linux Foundation present an open-source project.
“IBM had 80,000 lines of code it wanted to donate, so we worked with the Linux Foundation leadership to set up the Open Mainframe Project,” says Dickens. “I was its first chair.”
From there, the Open Mainframe Project has evolved from customizing programs using that original Linux code to creating open-source tools such as Zowe and beyond. “I’d like to say we had the vision that it would include z/OS, VSE and all of the other operating systems, but I think probably at the time we were more focused on the Linux side. The mission has certainly changed and morphed over time,” says Dickens.
As the Open Mainframe Project enters its second decade of existence, it has become a cornerstone of the mainframe ecosystem. But to get to this point, a group of competitors had to come together in recognition that they could go farther if they worked together.
The Genesis: Herding the Cats
While Linux had been available on IBM Z since 2000, the formation of the Open Mainframe Project and introduction of LinuxONE marked IBM’s commitment to creating a powerful mainframe that was accessed via a familiar OS.
“It was this amazingly strong Linux box that had scalability, stability and all of the big things mainframes are known for,” says John Mertic, director of program management at the Linux Foundation. “Using it was like modernizing your infrastructure, and then you added this well-known operating system.”
Besides IBM, the 14 founding members of this collaboration included SUSE, CA Technologies (now Broadcom), BMC Software, Vicom Infinity (now Pellera Technologies) and ADP. Marist College and the University of Bedfordshire were academic participants. And at the same time the project was announced, IBM partnered with Canonical to make its Ubuntu OS available for IBM zSystems hardware.
Many of these organizations and enterprises that came together for the Open Mainframe Project were competitors driven by a recognition of shared challenges. “This was because of how tech stacks evolved,” says Mertic. “They realized they were competing on specific unique features, but the tech stack was just a very common layer they all used. So why not develop that part collectively and focus our engineering resources on higher value items up in the stack.”
This was the 1990s, when software and hardware companies were very cautious about their proprietary products and worried about how “giving away” a product could reduce sales. “Many didn’t know how open-source software could work and worried that it would hurt their revenue stream,” says Len Santalucia, chairperson of the Open Mainframe Project’s governing board. “Now we see how open-source and copyrighted source software can easily coexist. We found that the open-source software wasn’t replacing the proprietary product, it was actually enhancing it. People started noticing that mainframes that had Linux installed along with z/OS and z/VSE and z/VM … had a tendency to grow faster than those that didn’t use Linux.”
This model was deemed more economically sensible, as opposed to each vendor developing their own proprietary solutions for every component, which could be costly and slow. “The Open Mainframe Project was considered essential because the challenge of modernization and sustainability was bigger than any one of us,” says Mertic. “We saw it as the natural gathering point needed to ‘herd all the cats’ in the mainframe industry.”
Accomplishments: Zowe, COBOL and the New Generation
While its initial focus was on using Linux with IBM Z machines, the Open Mainframe Project quickly expanded its mission to address the modernization needs of the predominant mainframe OS, z/OS. The core idea was simple but revolutionary: to make the experience of working with a mainframe similar to working with a web service or writing code in Python.
This culminated in the 2018 launch of Zowe, the first open-source framework for z/OS. Zowe opened up mainframe access to a new wave of developers. The project’s ethos was cemented at a SHARE conference shortly after its release when, in response to a question about the project’s roadmap, Dickens declared that the “roadmap is whatever you all want it to be.” This, he explained, was because it felt like Zowe belonged to the entire mainframe community and could be used by anyone. It represented a new democratization of the mainframe ecosystem, wherein the users determined the project’s direction rather than a single vendor.
The metrics confirmed Zowe’s massive success. It won a DevOps Award in 2023, and 85% of mainframe users had planned to adopt it the end of 2024. Zowe is considered a huge project within the Linux Foundation’s landscape, ranked among the top open-source projects tracked for code velocity and vibrancy.
Another sign of the peaceful coexistence of proprietary and open-source software is the extent to which software providers have incorporated open source into their products. Zowe has been adapted by IBM, Broadcom, Rocket Software and others to help manage the z/OS environment, says Santalucia. He adds that Feilong, the Open Mainframe Project’s z/VM Cloud Connector that provides virtual resource management for z/VM, has proved its value an API. “Open source has been good for the mainframe hardware itself, but also a lot of the central software that’s run on the mainframe as well,” he says.
Propelled by its early momentum, the Open Mainframe Project expanded its scope in 2020, offering a home and infrastructure for numerous technical initiatives. The project, which started with only a few foundational initiatives, now hosts around 20 sub-projects, working groups and programs. The organization’s Technical Advisory Council directs and coordinates its technical activities and works to build community support. Some key accomplishments include:
Talent Development
Recognizing the value of community building, the Open Mainframe Project’s Mentorship Program was established in 2016 to give students interested in mainframes hands-on experience. The program has seen exponential growth, receiving over 1,600 applicants in 2024. The project has also launched educational courses, such as Mainframe Open Education and the COBOL Programming Course, which aims to educate the next generation of mainframers using modern tooling and equipment rather than the “green screens” of yesteryear.
Language Modernization
During the COVID-19 pandemic, the Open Mainframe Project launched a program focusing on the need for COBOL developers. This led to the creation of the COBOL Programming Course and the COBOL Working Group that helped to dispel the myth that COBOL developers were a dying breed and helped educate students and those who needed a refresher. Additionally, COBOL Check, a unit test framework for COBOL, was launched in March 2021 and now works closely with Galasa and Zowe.
Hybrid Integration
The Open Mainframe Project’s Special Interest Group (SIG) for OpenTelemetry on Mainframe, in partnership with CNCF, enables an open-source framework for observability in mainframe environments. The project’s goal is to bridge mainframes with modern hybrid cloud observability and create solutions that make mainframe telemetry portable and usable with standard tools.
Community Reach
Membership in the Open Mainframe Project has grown significantly, from just 14 founders to nearly 40 member organizations today. The project’s marketing committee has been instrumental in building the group’s brand, changing the perception that mainframes are antiquated technology by showcasing the platform’s modernity and the diversity of its developers.
The Future: AI, Security and Continued Collaboration
After celebrating its “Decade of Developers, Community and Mainframe” in 2025, the the Open Mainframe Project looks forward, believing the momentum for open source collaboration is strong. Its fundamental goal remains ensuring the sustainability of the platform, aligning with the community’s unique interest in shaping the mainframe ecosystem in the future. For the next decade, its vision is to fully solidify the open source model. Leadership is hoping for the emergence of three or four new projects achieving the immense scale and influence of Zowe.
The organization’s next generation of major projects is already taking shape in cutting-edge areas such as AI. This is already reflected in newer projects like Zorse, which is collecting data sets to help large language models write and better understand COBOL. Other critical future focus areas include building out security frameworks and participating in the standardization of quantum-safe standards alongside bodies like the National Institute of Standards and Technology (NIST).
Organizationally, the Open Mainframe Project community is supported by its Ambassador Program, featuring individuals who are passionate experts willing to help others learn about the technology. And in 2025, the project launched Mainframe Connect, a new platform with podcasts, videos and blogs designed to bring together regular content, conversations and collaboration regarding the mainframe, its people and open source.
The Open Mainframe Project continues to serve as a critical common space for this unique corner of technology. It’s proof that when competitors recognize the non-competitive nature of foundational layers, they can dramatically accelerate innovation, ensuring the mainframe remains not just alive, but thriving.
“We’ve made some great strides in the first 10 years, but I don’t think we’re finished,” says Dickens. “If I could ask for one thing, it’s that the big vendors further embrace, triple down, quadruple down and invest in open source. I think we’ve broken the seal, but we’re not at the end of the job.”