Mainframes are computers

At their core, mainframes are high-performance computers with large amounts of memory and processors that process billions of simple calculations and transactions in real-time.

Read on to learn more about mainframes:


How are mainframes unique?

The IBM mainframe is uniquely engineered to:

  • Run common operating systems like Linux, as well as specialized operating a systems such as z/OS and software to take advantage of the unique hardware capabilities.
  • Support more simultaneous transactions and higher levels of throughput (I/O) compared to other computers through built-in capacity on demand and a built-in Internal Shared Memory solution.
  • Deliver the highest levels of security by building cryptographic cards into the hardware.  
  • Offer resiliency through multiple layers of redundancy for every component (power supplies, cooling, backup batteries, CPUs, I/O components, cryptography modules) and testing for extreme weather conditions.

What are the core design values?

The mainframe is critical to commercial databases, transaction servers and applications that require high reliability, scalability, compatibility, and security – its core design values.


Mainframes isolate workloads, authenticate access and can uniquely encrypt 100% of data and protect it after it leaves the system, minimizing the impact of breaches.


Mainframes offer high availability and disaster recovery. IBM Z customers report only 8.8 seconds of annual downtime; that’s 99.9999% uptime.¹


One mainframe can execute up to 1 trillion secure web transactions per day. IBM z15™ delivers high performance with up to 190 configurable cores and up to 40 TB memory.

What does a mainframe look like?

Today’s mainframes are much smaller than the early “Big Iron” machines. With a standard 19” rack, the latest mainframe seamlessly coexists with other platforms in the data center. One z15 single-frame system requires 75 percent less floor space than x86 2U servers running the same workloads and throughput – and reduces power consumption by 40 percent.

Who uses IBM mainframes?

Today, many of the world’s top companies use mainframes — 44 of the top 50 banks, many government and healthcare organizations, and all top 10 insurers.


Allied Irish Bank uses the agility of the IBM Z platform to deliver open banking and new functionality.

Government agencies

The Department of the Treasury of Puerto Rico deploys a continuous availability solution to ensure maximum uptime.

IT service providers

Emid delivers a software platform on IBM Z and gains simplicity, resilience, data privacy and security.

And you

Play the game that shows you how much of your everyday experiences are likely to depend on a mainframe.

Mainframes have a history of technology breakthroughs

A history of firsts

From the beginning, the mainframe was built to take businesses to the next level.


New technologies on the mainframe made centralization possible.


Mainframe capabilities like built-in virtualization made the cloud possible.

Pervasive encryption

Mainframes continue to innovate to remain the most secure platform.

What’s next for mainframes?

What’s next for innovation

From blockchain to quantum computing, the IBM mainframe is ready to deliver the computing power for what’s next.

What’s next for careers

Mainframe developers are in high demand, with starting salaries that are higher than most other college graduates.

What’s next for customers

Enterprise customers are expected to gain over USD 190M in revenue impact, 44% reduction in unplanned outages and 2x more DevOps agility.

What does a mainframer do?

Luisa Martinez

Luisa tries something new – developing on the mainframe.

Alex Stuart

Alex describes how he is “splunking the mainframe.”

Meghan McGrath

Meghan shares how she helped bring 100% encryption to the mainframe.

How can you get started on the mainframe?

Get hands-on learning

Use this learning system to go from novice to a skilled mainframer.

Create an app

Use these tutorials to create an app that accesses the mainframe.

Try software

Try mainframe software at zero cost, and with no installation required.