How the mainframe is modernizing, according to today’s IT pros

John McKenny began his mainframe career in 1981, managing printers and reports generated by a powerful, refrigerator-size computer built to process and automate then-paper-based workflows at railway company CSX Technology.

Forty-plus years later, McKenny, now SVP and general manager for BMC Software’s mainframe business, helps clients operate and optimize the same mainframe technology from his railroad days—only the tech is now faster, sleeker, smaller, and AI-equipped.

While it’s tempting to think that virtually all modern enterprise IT workloads live in the cloud, or at least within on-premises hardware conceived and designed within the past 20 years, today’s mainframes still support critical applications in insurance, banking, government, and many other firms handling lots of transactions.

But what does the future of the mainframe look like, as more companies push to the cloud and begin to lose track of old languages (like COBOL) found in the decades-old hardware? We spoke with mainframe engineers like McKenny about how the mainframe is modernizing and opening its giant doors to emerging technologies and emerging enthusiasts.

The main idea. A mainframe, a large-capacity computer with very high processing power, got its name from “the large cabinet or ‘main frame’ that held the central processing unit (CPU) of early computer systems,” according to IBM. IBM’s “Mark I,” designed in 1937, is considered the first mainframe computer. While early models had dimensions ranging from 2,000 to 10,000 square feet, says IBM, newer releases throughout the decades have shrunk to a more modest size, perfect for slotting into a data center.

Mainframes enable transactions at blazing speeds. IBM’s latest-gen mainframe system, the z17, released in April 2025, for example, boasts a processing capability of “up to 5 million inference operations per second with less than 1 ms response time.”

The mainframe, by design, has built-in features supporting can’t-fail applications, including redundant hardware components, a workload-balancing structure called logical partitions, and advanced warnings of a faulty part.

“I’ve gotten calls from IBM throughout my career, and they’ve said, ‘Hey, one of your memory modules is failing. We’re on our way to replace it’…and nobody has any idea that that failure occurred,” Steven Perva, an expert mainframe innovation engineer at Ensono, told IT Brew.

A modernized mainframe. Almost a century after their creation, mainframes, given their central role to many businesses, have remained in data centers and taken on new features.

• One way to modernize, according to Perva, involves changing the software development approach for mainframes. Perva has been using new extensions to enable tools and capabilities familiar to non-mainframers, such as the AI code editor VS Code, the remote-access management interface SSH, and Microsoft Copilot code explanation.
  
  Before these access methods, applications were (and still are, according to Perva) typically developed via TSO/ISPF command-prompt interfaces, also known as “green-screen” interfaces featuring Matrix-like green text on a black background. API connectivity, introduced by the z/OS Management Facility tool has enabled new coding options, Perva wrote to us in a follow-up email.
  
  “It’s almost like a kid having a job that says, ‘Hey, we have all these new toys that are coming out. We want you to tell us which ones are fun,’” Perva said.
  
  McKenny, too, has seen developers use similar code tools to write and update an application running on the mainframe. “By developing that in VS Code, they have access to look at and interact with information from the mainframe about that application, to get an explanation of that application, to get some insights as to how it works and all that can be done in a modern interface,” McKenny told IT Brew.
• Many mainframes feature COBOL—the “Common Business-Oriented Language” invented in the 1950s. Expertise is currently in high demand, as modernization, for some, might mean getting rid of all that COBOL.
  
  Hassan Zamat, SVP at Kyndryl and the global practice leader for core enterprise and its mainframe-as-a-service platform zCloud, uses generative and agentic AI tools to translate legacy code like COBOL into modern programming languages like C# or Java, in addition to recommending architectural improvements.
• Modernization could also mean a “hybrid” approach, pulling some on-mainframe functions into virtual mainframe environments in the cloud. A common “hybrid” scenario Perva sees: Orgs will move their development environments off the mainframe. “We see a lot of people who want to automate their testing, and they’re not developing all the time, so it doesn’t make sense for them to have a dedicated, forever-running development environment,” Perva said.
• Tools like BMC’s AMI Ops and IBM Z’s AIOps use AI capabilities to monitor for disruption-causing events.

The youth are here. BMC’s annual mainframe survey, released in September 2025, revealed an emerging interest in the mainframe from younger IT professionals. Around 66% of the more than 1,000 global mainframe practitioners and stakeholders surveyed identified as millennial or Gen Z—an increase from 37% in 2018. Almost all (97%) of this year’s total respondents see the mainframe as a long-term platform or platform for new workloads—like generative AI assistants and even faster fraud detection and credit-risk scoring, McKenny shared as a few examples.

McKenny hopes to retire in the next 10 years or so, he said, leaving a place for a new generation responsible for taking the platform forward. “When you have someone that has a responsibility to develop on, to secure, to manage, to operate this environment for the next 15 or 20 or 25 years of their career, they’re more interested in looking at, ‘Hey, what are some of the new and different ways that we can exploit the power of this platform?’”