Looks Like IBM Is Building A Linux-Like PASE For IBM i After All

June 16, 2025 Timothy Prickett Morgan

It is pleasing, indeed, whenever you think of something that would be useful for a particular platform and then you find out that the company is working on it. This is indeed what I thought of when we reviewed the IBM i – A Strategic Preview For 2025 And Beyond session hosted by IBM i chief technology officer Steve Will at the recent POWERUp 2025 conference in Anaheim, California. I was not able to attend the event, but my co-editor, Alex Woodie, was able to, and hence we were quite pleased to see that Big Blue is apparently working on something of an analog of the PASE AIX runtime embedded in the IBM i operating system that could be used to host Linux applications.

This is something that is long overdue, given that Linux has been the only operating system that is growing its footprint in the world and that so much new and interesting application and systems software runs on Linux. I have been hinting at this in many different ways over the years as Linux grew in popularity, but more fully expressed a need for a native Linux runtime to be embedded within IBM i back in May 2023 in OpenShift Can Be The New PASE For IBM i Shops. The idea was to thread a couple of needles at the same time, to bury a Linux runtime and also a Kubernetes container platform within a Power Systems partition but to make it all look like it was native inside of IBM i, much like the Portable Application Solution Environment, or PASE, which dates from June 2000, just when Linux was entering the enterprise and Unix was ascended in the datacenter, and which was embedded in OS/400 V4R5.

That OS/400 V4R5 release was the first one to allow for the mixing of multiple operating systems of different release levels and types to be run on a single hardware platform within the relatively new hypervisor that would eventually be known as PowerVM. It also allowed up to 24 partitions on a machine, double that of V4R4, which actually used a variant of OS/400 to host OS/400 partitions. PowerVM was based on the same ideas of host and guest partitioning, but had an AIX kernel at its heart. That V4R5 operating system also included integration with Windows Server, which allowed for Windows NT Server 4.0 or Windows Server 2000 to be deployed on integrated Netfinity Servers. These were previously known as the Integrated File Serving I/O Processors, which made their debut way back in 1995 running IBM’s OS/2 LAN Server, Novell’s NetWare, and Lotus Development’s Notes. Because AIX and Linux run natively on Power, they did not have to be offloaded to an X86 server running on a baby server plugged into the peripheral bus. PASE runs as a kind of hosted runtime adjacent to the IBM i operating system kernel, and a variant based on Linux – which I called the Portable Linux Enterprise Application Software Environment, or PLEASE for short – could do the same.

I was greedy and also wanted for a Linux container system based on Kubernetes to be part of this, but that may have been a bridge too far based on what Will said in his strategic preview. Here is what Will said in full, so we get the entire flavor of his thinking about what PLEASE might look like:

“This is more forward thinking than I typically talk about, because I don’t have something on the roadmap I can tell you is coming within the next year. But we have to address the fact that so much of the open source is being used in the world, resides on Linux, and may never, ever get moved to AIX.”

“And so we have to find a way to incorporate Linux-based open source into IBM i better.”

“Now that may not be actually running it in IBM i. There is a work process underway in Power to make it easy for people to deploy a Linux Power partition and connect it to IBM i and sort of make it look like it is all one thing. Okay. It’s not to a point where I can discuss or announce anything, but that’s the kind of direction we are going. We could make it look like the open source is running Linux on Power and is connected to you in much the same way that PASE is connected to you. You will not have to deal with all the complexities of having Linux partition. We’re not talking about doing it with an OpenShift cluster or anything like that. It is just very, very simple. And that’s kind of the future that I think IBM i needs to get to now.”

There are many things that are brilliant about the OS/400 and IBM i platform, and PASE, which was originally called the Private Address Space Environment until the marketeers at Big Blue got out their random name generator, is one of them. And we think PLEASE is long overdue and are glad that IBM is doing something to make the vast store of Linux applications and systems software – and maybe even compilers – look transparently native to IBM i shops.

PASE is how IBM i gets its TCP/IP networking stack, support for the MySQL and other non-IBM i databases, as well the ability to host a slew of runtimes for various compilers. (Rust could be next, now that IBM has a native Rust compiler for AIX, which we reported about here in February and suggested should be moved to IBM i via PASE in May.) Frankly, there could be a lot of stuff running in PASE that we don’t even know is in PASE – and that is kind of the whole point. You don’t know and you don’t have to care. You load a bit of AIX software, it has the right API hooks into IBM i, and you could care less that you are actually running a hybrid IBM i-AIX environment.

Here is the deal: This time around, both AIX shops and IBM i shops do not want to have to manage separate Linux partitions or clusters on Power Systems partitions to be able to absorb modern Linux applications. Both AIX shops and IBM i shops no doubt want the ability to transparently and effortlessly support Linux applications on their systems without hiring Linux nerds. So now, the part of the Power Systems base that has the most customers (IBM i) and the part of the Power Systems base that generates the most revenues (AIX) have needs that are aligned.

WatsonX AI systems software is the first obvious killer application to run on IBM i and AIX systems. Which is why we will say it again: IBM should create a PLEASE runtime that runs monolithic as well as containerized Linux workloads under the covers of IBM i and AIX but is really a full OpenShift Kubernetes environment that looks native to IBM i or AIX for a Linux workloads. Make it so no one knows and no one cares, just like PASE. Make PLEASE just work.

By doing this, IBM can both proliferate the OpenShift stack across its enterprise customer base and to help IBM i and AIX shops get more workloads off X86 iron and onto Power iron, thereby making the Power Systems platform more central to the business. This will in turn create a virtuous cycle that improves computing at IBM i and AIX shops and thereby drive more sales of Power Systems, and so on and so on . . . .

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