IBM killing mainframe coding kit for PCs this year

IBM is killing off a mainframe coding toolkit for PCs and withdrawing all support, directing developers to instead use a cloud-hosted environment for dev and test purposes.

In a notice issued on September 30, Big Blue informed customers that it will cease marketing the System z Personal Development Tool (zPDT) as a standalone offering, effective from December 31 this year. Support for the product will be discontinued a year later, on December 31, 2026.

The IBM zPDT emulates one or more System z processors, the CPUs used in IBM Z mainframes, on a PC running Linux. This provides a small System z instance capable of running currently supported operating systems, with emulation of selected System z I/O devices and control units.

IBM warns that zPDT is strictly intended as a development, demonstration, and learning platform and not designed as a production system, should one be tempted to do this, particularly as x86 boxes lack the famous reliability and availability of Big Blue's big iron.

The intended replacement for zPDT is IBM's hosted on-demand program for independent software vendors (ISVs), which is set to provide them with on-demand IBM z/OS environments, dynamically provisioned through "near-seamless" automation for test and development purposes.

We say "set to" as the planned availability date for this particular offering is October 31, 2025.

To get access, developers must participate in the IBM Partner Plus program, and it issues similar warnings that using the forthcoming ISV solution for production, work-for-hire activity, outsourcing workloads, or any commercial purposes is strictly prohibited.

We asked IBM why it was withdrawing the zPDT, since a tool that developers can run on a PC would seem like a good way of encouraging them to code for System z, or at least maintain familiarity with it.

In response, a spokesperson for Big Blue told us: "IBM is focused on improved performance, security and user experience for our ISV community. IBM is pleased to offer a new, upgraded IBM z/OS hosted on-demand program for ISVs, providing a turnkey, simplified experience."

The new solution will provide ISVs with on-demand IBM z/OS environments, running on Linux, with emulated I/O, all hosted within an IBM datacenter for improved performance, we were told. Each provisioned environment is derived from the IBM z/OS Standard Image with the latest software maintenance incorporated to ensure security and operational efficiency.

"This is a strange one, as a PC SDK is mostly for encouraging wider adoption," commented Omdia Chief Analyst Roy Illsley.

"My best guess is that it is about cost, having a single cloud-based environment is cheaper to maintain, and with AI they can build an AI agent faster and quicker in the cloud so that specific mainframe knowledge becomes less of an issue for them. Those are only reasons I can think of," he told The Register.

• Cloud computing has become so normal, it's invisible
• Oracle extends 19c database support to 2032, making it 'longest strategic release'
• Debian 11 formally debuts and hits the Bullseye
• Ubuntu unleashes Mantic Minotaur with 23.10 build

However, IBM does have another PC mainframe developer tool, the Z Development and Test environment, (ZD&T). This enables any z/OS software to run on an x86-compatible on-premises system or cloud instance by emulating the IBM Z instruction sets.

We asked IBM if it was also planning to discontinue this product, but the company responded simply that the IBM z/OS hosted on demand program for ISVs is designed to be the best fit for the needs of ISVs in the IBM Z ecosystem.

Then there is the open-source Hercules emulator, but this is unlicensed and only implements the raw System z instruction set; it does not provide any operating system. IBM frowns upon its use, of course. ®