An in-depth look at mainframe computers, their 50+ year history, and the IBM mainframe, a business mainstay that represents most of the estimated 10,000 in use
over and over — where me and my colleagues are advising leaders to let the mainframes be, amidst their grand “transformation” plans. Twitter: Peter Zaitsev / @peterzaitsev : In some sectors technology moves super fast, in others... we may be still operating software designed decades ago https://arstechnica.com/... Robert Scoble / @scobleizer : They are still used. I know a guy who programs one for a bank. Great career. Glenn K. Lockwood / @glennklockwood : This is a very detailed but digestible tour of what makes mainframes quite different from commodity severs and why they persist. Worth a read. The IBM mainframe: How it runs and why it survives | Ars Technica https://arstechnica.com/... Threads: Tom Gara / @tomgara : Thing I learned: IBM still makes giant closet-sized computers that run on an IBM operating system and use IBM chips, and basically the entire banking system runs on them... Forums: Hacker News : The IBM mainframe: How it runs and why it survives r/technology : The IBM mainframe: How it runs and why it survives Ars OpenForum : The IBM mainframe: How it runs and why it survives
Context & Ripple Effects
This retrospective lands at a moment when the mainframe's obituary keeps getting postponed. IBM has spent a decade refreshing the platform rather than milking it — the z13 built for 30,000 transactions per second in 2015, then opening the stack to open source via LinuxONE running Ubuntu under the Open Mainframe Project, then the quantum-resistant z16. Each cycle re-armed the same argument the article makes: the installed base isn't legacy, it's load-bearing.
First-order effects
- Advisers like Peter Zaitsev are telling enterprise leaders to leave mainframes out of 'transformation' plans, and the piece gives them evidence: most of the estimated 10,000 systems still in production are IBM machines running core banking, insurance, and airline workloads that commodity servers don't replace cheaply.
- IBM's own numbers show why the franchise matters — infrastructure revenue of $3.8B, down 7% year over year, makes each retained mainframe customer disproportionately valuable against the decline.
Second-order effects
- Cloud vendors are the party losing the argument: as the related coverage shows, some banks, insurers, and airlines now prefer running AI locally on mainframes rather than shipping those workloads outward, keeping data and transactions inside the same box that already clears them.
- The talent market tightens around a shrinking pool — the Scoble anecdote about a bank mainframe programmer having 'a great career' points to scarcity pricing for COBOL-and-z/OS skills as the cohort retires faster than it grows.
Third-order effects
- The pattern echoes the DEC story in the related coverage: the minicomputer pioneer that mainframes supposedly displaced was itself absorbed by Compaq by 1998, while the platform it attacked persisted — a reminder that in fashionized computing, the unglamorous incumbent often outlives its disruptor.
- If the AI-on-mainframe pattern holds, IBM consolidates transactional and inference compute for regulated industries into a single vendor relationship, raising both its pricing power and the regulatory scrutiny that comes with being a single point of failure for financial infrastructure.
The trend: Computing fashion cycles keep writing off the mainframe, yet each technology wave — open source, quantum-safe encryption, now local AI inference — gets absorbed into the same IBM-installed base rather than displacing it.