First Steps on the Mainframe

There is something deeply humbling about working with a mainframe for the first time. Not because it is hard — though it is — but because you realise how much of the world silently depends on these machines.

The silence around z/OS

Nobody talks about mainframes. In university nobody mentions them. In job postings they appear rarely. And yet the majority of global banking transactions, airline reservations, and insurance records run on IBM Z systems. Every day. Without drama.

That silence is not because mainframes are irrelevant. It is because they just work.

COBOL is not a joke

When people find out I write COBOL they laugh. I used to laugh too. Then I actually read COBOL code.

COBOL is verbose, yes. But it is also readable in a way that almost no other language is. Business logic written in COBOL in 1985 can be understood by a non-programmer in 2026. Can you say the same about your microservice spaghetti?

The language was designed for clarity and longevity. It achieved both.

What I got from the IBM Z Xplore program

The IBM Z Xplore learning path forced me to actually sit with the tooling — JCL, ISPF, SDSF, z/OSMF. Not to watch videos about it, but to type commands and see what happens.

Getting the All Star badge meant completing tasks across multiple disciplines: COBOL, Assembler, Rexx, and z/OS operations. It changed how I think about system-level software entirely.

Why it matters to me

I care about bare metal. I care about understanding what the machine is actually doing. Mainframes are the extreme end of that: hardware and software co-designed over decades to be reliable, fast, and verifiable.

If you have never touched a mainframe, I genuinely recommend trying. Your perspective on computing will shift.