The IBM i OS Base Is Older Than We Think, But Moving Ahead

March 6, 2023

Timothy Prickett Morgan

Hardware upgrades are costly in terms of money and while it is always exiting to get a new system with that “new computer smell” – and you know what we are talking about – at least IBM i operating system and systems software upgrades don’t carry such a high price – provided you are on Software Maintenance and you do proper testing on your software before you make a jump to a new release.

The other great thing about IBM i systems software is that any given release not only runs on the current new Power Systems hardware at the time, but also on several prior generations of hardware, and older releases are updated to cover new hardware as it rolls out, too. Add in the Technology Refresh updates for the past several IBM i generations and it is considerably easier to stay current on IBM i software than it is on Power Systems hardware – and much less expensive, too.

The question is, how current are companies when it comes to their IBM i stack. We get some sense of that each January when the IBM i Marketplace Survey report comes out, which details the results of the survey that happened during the fall of the prior year. The survey, which is done by Fortra (formerly known as HelpSystems), has been in the field for nine years now and gives us a rich set of data from which to try to understand the IBM i base.

As we pointed out last week when we analyzed the Power Systems installed base among the IBM i faithful, we think that the data gathered by the survey reflects the state of the active part of the IBM i base, which we reckon is about 30,000 unique customers and does not indicate the vintage of hardware and systems software at the remaining 90,000 customers worldwide, what we call the laggards.

This active-laggard split is admittedly a hunch that we have, but it is that is informed by anecdotal evidence from customers and business partners who tell us far more vintage System/38, System/36, AS/400, iSeries, and System i iron has stayed in the field longer than any survey data ever shows. We think these laggard customers are stuck on vintage and unsupported software from third party vendors who may not even exist anymore or who charge too much money to upgrade applications to current releases. We think that active customers are the ones who tend to read publications like The Four Hundred, to go to COMMON and other user group meetings, and to take the time to do surveys. And we think that the Fortra survey, to be specific, is absolutely representative of what active customers are doing in terms of Power Systems and IBM i release levels.

We know that the laggards are quite a bit further back, although by how much is not clear. We reckon it is about four years or so behind the active part of the base, but following a similar path. Last week, we took the dataset of Power Systems distribution by Power CPU family from the nine Fortra reports and did a little witchcraft on it to figure out what the machine base at the remaining 90,000 sites might look like. This week, we are looking at the primary IBM i releases installed at sites.

The IBM i Marketplace Survey allows respondents to report on all Power Systems machines they have in their company, not just the primary machine’s type. But when it comes to the operating system, it asks for the primary one. This stands to reason, since if you have two machines (or three) in a high availability or disaster recovery configuration, you will probably be at the same hardware and software release. But some companies have separate machines for test and development and other uses, perhaps out in the field, and these can be at different hardware and software releases.

Here is what the raw data for primary IBM i operating system installed for the past five years:

In this raw data, we see that IBM i 7.5, which came out in May 2022, was cited by 2 percent of respondents, and we can see the rise of IBM i 7.4, which was cited by nearly half of respondents in the survey that ran last October. You will also note the decline of IBM i 7.3 after a pretty long run, and the decline of earlier releases as well.

We like to get an even longer view, and in more distinct colors and patterns that are easier to see, and so we put together this chart with all nine years of data:

We have estimated the distribution of earlier OS/400, i5/OS, and IBM i releases based on past data, when these were all called out separately. We think this is pretty representative of the OS distribution over time among the 30,000 active customers. As you can see, IBM i 7.5 is just starting out its climb.

But we do not think for a second that it is representative of what is going on at the laggards, and therefore for three-quarters of the installed base. We do not for one second believe that IBM i 7.4 is nearly half of the installed base and that IBM i 7.3 is nearly 40 percent of the base. No server operating system has 90 percent of its customers on the two current releases. Not Windows Server, not Linux. Not the IBM System z mainframe and its z/OS platform.

We created a model last year that showed that more than half of the base was actually on IBM i 7.1, which is consistent with the anecdotal evidence we get from customers and partners by time shifting those laggards to the distribution of operating systems that we saw on the IBM i Marketplace Survey four years ago. If you do that, you get a distribution of primary operating systems – including both actives and laggards added together – that looks like this:

Just for fun, we are going to let you see the model data that we generated for the 2022 and 2023 installed bases:

Here is what is interesting. The IBM i 7.4 base is growing very fast, and we think that this is customers moving up from IBM i 7.2 and in some cases IBM i 7.3. But funnily enough, the base of IBM i 7.2 is growing as customers upgrade from IBM i 6.1 and to a certain extent IBM i 7.1, and even though the IBM i 6.1 base is down, it is being propped up by those moving from i5/OS 5.4 and in some cases OS/400 V5R3. And IBM i 7.1, in our analysis, represents half of the IBM i base, not IBM i 7.4, and this has some important implications.

You can’t fault IBM for this, either. The company has done wonders with the Technology Refresh method of updating software functionality across three concurrently supported releases, and one of the side effects is that people are taking advantage of the seven years of support and can do so without sacrificing major functionality. That generosity is extending the effective life of IBM i releases. But the IBM i 7.1 base grew in the past 12 months – not by much, but by a few thousand customers. And if we are right, that is a big problem in the long run.

Last week, when talking about hardware, and in a bit of a haze because I was writing late at night, I said that IBM should worry less about what IBM i versions and releases it can support on PowerVM logical partitions on a particular Power10, Power9, and Power8 system and more about how it can use the Technology Independent Machine Interface, or TIMI, to make a Power10 processor look like a Power9, Power8, Power7+, or Power7 processor, and maybe older CPUs and their systems. Rather than trying to update everyone to more modern hardware and operating systems, why not convince older releases of OS/400, i5/OS, and IBM i that they are actually running on whatever hardware they expect? This would mostly mean hiding more modern features, not taking away old stuff.

So we ask again: Why can’t TIMI and microcode make any new Power processor look like any older Power processor? With such an approach, you could in fact move everyone to Power10 and just leave their software – operating system, database, systems stack, and applications – as they are. Why not?


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