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IBM Z: the computer that never learned how to die

Most computers are replaced every few years.

IBM Z systems are different.
They are designed to run for decades.

IBM Z is not a normal CPU platform. It is a mainframe architecture built for reliability, security, and massive workloads.

This is the kind of computer that banks and governments trust with everything.

What IBM Z actually is

IBM Z is both:
• a processor architecture
• a complete mainframe system

The instruction set used by IBM Z is commonly called s390x.

This architecture is designed for:
• extreme uptime
• huge input/output workloads
• running thousands of tasks at the same time
• backward compatibility across generations

Programs written decades ago can still run today.

What makes IBM Z different from normal CPUs

IBM Z does not try to be fast like a gaming CPU.

It tries to be:
• correct
• stable
• secure
• always available

Key design goals:
• systems that almost never go down
• hardware-level encryption
• fault tolerance built into the CPU
• predictable performance under heavy load

If a normal server fails, you reboot.
If an IBM Z system fails, something went very wrong.

Backward compatibility is sacred

One of the most impressive things about IBM Z is compatibility.

Software written:
• 20 years ago
• 30 years ago
• even older

can still run on modern IBM Z machines.

IBM treats backward compatibility as a rule, not a suggestion.

This is why companies never rush to replace mainframes.

Operating systems that run on IBM Z

IBM Z has real operating systems, not custom firmware.

z/OS

z/OS

This is the main operating system for IBM Z.

Used for:
• banking systems
• airline reservations
• insurance databases
• government systems

It is built for:
• huge transaction volumes
• extreme reliability
• long uptime

Linux on IBM Z

Linux runs very well on IBM Z.

Linux on Z is used for:
• cloud workloads
• containers
• databases
• enterprise applications

Yes, you can run Docker and Kubernetes on IBM Z.

z/VM

z/VM

This is a virtualization operating system.

It allows:
• thousands of virtual machines
• strong isolation
• efficient resource sharing

IBM Z was doing large-scale virtualization long before it became popular elsewhere.

Who actually uses IBM Z today

IBM Z is not rare.

It is used by:
• banks
• stock exchanges
• airlines
• governments
• large insurance companies
• telecom providers

If you:
• withdraw money
• book a flight
• swipe a credit card

There is a good chance IBM Z was involved.

Why companies still use IBM Z

Main reasons:
• downtime is extremely expensive
• security is critical
• systems must scale reliably
• rewriting software is risky

IBM Z systems can:
• process millions of transactions per second
• encrypt data without slowing down
• run for years without shutdown

For some workloads, nothing else compares.

Modern IBM Z systems

IBM Z is not old hardware running forever.

IBM still releases new machines.

Example:
• IBM z16 (modern generation)

Each generation improves:
• performance
• energy efficiency
• security features

But still keeps old software working.

Is IBM Z outdated?

No.

It is specialized.

IBM Z is not for:
• gaming
• personal laptops
• hobby projects

It is for:
• mission-critical computing
• workloads where failure is not allowed

Different tools for different jobs.

Why IBM Z will not disappear like DEC Alpha

DEC Alpha died because the company behind it disappeared.

IBM Z survives because:
• IBM is still committed
• customers depend on it
• the ecosystem is stable
• migration costs are huge

IBM Z is not trendy and that is its strength.

Final thoughts

IBM Z is the opposite of modern tech hype.

It changes slowly.
It breaks nothing.
It keeps running.

While most computers chase speed, IBM Z chases trust.

And that is why it is still here.

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