(Speaking for myself, not my employer.)
This is the end of the FLEX-ES all over again, 20 years later, and before that the end of the MPx000 line again.
IBM really messed this up horribly. As an IBM Champion I am ashamed and upset that somewhere in the management hierarchy small ISVs are completely overlooked, yet they are that little stick in the mainframe version of the xkcd drawing.
M. Dupré has excellently summarized the issues that IBM created through their missteps. My biggest concern-and the same one that I point out in the other cost barrier to entry issue, education & hobbyist-is cost control. For ISVs, they need to budget just like the big ones. Variable costs can ruin a company when they run amok. And cloud is all about variable costs. This is why I hate the idea of cloud for education & hobbyist without appropriate guard rails. Imagine a bill when a process goes amok overnight when you're not actively monitoring and at the end of the month you get a bill that is a magnitude or higher than what you expected and budgeted.
I would love a play system. In fact, I bought a ZD&T LE package. It was extremely difficult, and I was one of the lucky ones to get one. But it's now useless because of how that was fumbled, and the suggested replacement (Wazi, funded by "get some credits!") for me was not an option because I couldn't control costs and a runaway bill could impact my personal financial life.
The current dongle-based system has always been a bit of a mess, but it wasn't enough of a mess to get in the way. Cloud is cleaner in some respects, but I believe they have introduced many more issues, as M. Dupré outlined above.
IBM says more info is coming, but the clock is ticking. Small ISVs whose fiscal years are tied to the calendar year have already made their budgets, and I'm sure many of them have had to set aside money and cut back elsewhere for the unknown. I see there's an ISV update in the TDT schedule, the last half hour on the last day. I'm not sure that's long enough to handle the discussion.
I've had ideas for a product and when I had the funds, the zPDT was a viable option. Now that isn't available, and the randomness of cloud pricing is dissuasive.
In the intermezzo between FLEX-ES and zPDT, many small ISVs went to the gray area emulation route. (I worked for one.) IBM looked the other way during that time because at least part of the company knew that other parts messed up. (I want to use stronger language but prudence here.) I'm afraid that the fixed cost rationale may lead some this way.
I talked about this earlier this month on the zMinds podcast with Sammie Clark. I discussed some of the higher level issues that M. Dupré also mentioned. There are also are spirited discussions going on over on the zPDT mailing list on groups.io.
I've been in the ISV arena for 35 years, 30 in R&D. I've worked on giant IBM Z systems and small zPDTs, even being the sysprog on one. It's a great system, and there's something to be said for being able to control all aspects of the platform.
I hope IBM can come up with a better temporary solution than what's been publicly said so far, and they come up with a better permanent solution that allows ISVs the same flexibility and fixed costs that the zPDT does.
IBM has to do better.
(I also hope I don't lose IBM Champion status for this rant.)
Cheers,
Ray
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Ray Mullins
Sr. Software Developer
Broadcom Mainframe Software Division
Roseville
United States
+19164123982
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Original Message:
Sent: Mon November 24, 2025 03:58 AM
From: Gatien Dupré
Subject: IBM Ends ZPDT: What Are the Alternatives for Mainframe Developers?
IBM Announces the End of ZPDT
IBM has confirmed the end of life for its ZPDT (System z Personal Development Tool):
- End of sales: December 31, 2025
- End of support: December 31, 2026
ZPDT allowed developers to emulate a System z environment on a Linux x86 server, enabling work on z/OS without a physical mainframe. This product was strictly intended for development, demonstration, and training, never for production.
A Cloud Alternative for z/OS Development
IBM now offers a z/OS on Demand solution hosted in the cloud:
- Access via the IBM Partner Plus program
- Environments based on standard IBM z/OS images, regularly updated
- Production use prohibited: strictly for development and testing
This move aligns with IBM's cloud-first strategy to modernize access to mainframe environments.
Impact on ISVs
Independent Software Vendors (ISVs) will need to adapt their practices:
- Reorganize workflows to integrate cloud environments
- Plan for variable costs due to pay-per-use billing
- Strengthen compliance and security measures
While this transition offers an opportunity to adopt more agile methods, it requires proactive planning.
Predictable Impacts for ISVs Using ZPDT Intensively
- Higher Operational Costs
ISVs running ZPDT continuously enjoyed a fixed amortized cost. With IBM z/OS on Demand, hourly billing (USD $1–$3 per hour) can skyrocket for long-running tests or 24/7 environments. - Workflow Reorganization
Moving from a stable on-premise model to a dynamic cloud model requires automation tools to manage provisioning and reduce costs. - Increased Dependence on IBM
Loss of full control over the environment and risk of vendor lock-in, as IBM dictates access, pricing, and conditions. - Compliance and Sovereignty Challenges
ISVs in regulated sectors must ensure data location compliance (e.g., GDPR). - Competitive Pressure
ISVs that fail to adapt risk slower development cycles or margin erosion.
Impact on Sovereignty
The shift to cloud raises digital sovereignty concerns:
- Data location: often outside national borders
- Technological dependence: reduced autonomy over infrastructure
- Contractual and geopolitical risks: changes in terms or restrictions could disrupt operations
For sensitive organizations (banks, government, defense), recommended actions include:
- Maintain ZD&T on-premise environments for critical needs
- Demand guarantees on data location and reversibility
- Explore partnerships with sovereign clouds or hybrid solutions
Quick Comparison: On-Premise vs Cloud
Solution | Initial Cost | Recurring Cost | Flexibility | Heavy Usage |
ZPDT | High | Low | Low | ✅ |
ZD&T | Medium | Medium | Moderate | ✅ |
Cloud | Low | Variable | ✅ | ❌ |
Innovation or Dependence?
By ending ZPDT and pushing a cloud solution, IBM claims to modernize mainframe access. But this raises a critical question:
Is this truly a step toward agility and performance, or a strategy to deepen enterprise dependence on IBM's ecosystem?
Conclusion
The end of ZPDT marks a turning point for the mainframe ecosystem. Organizations must prepare their transition now, choosing between ZD&T on-premise or z/OS on Demand, while ensuring security and sovereignty.
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Gatien Dupre (CPTO)
VIRTEL (Syspertec Group)
Phone: (+33)621166653
Email : gatien.dupre@syspertec.com
302 BUREAUX DE LA COLLINE SAINT-CLOUD (92210) France
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