Mainframe

Mainframe systems are still very much relevant in today's world, they no longer occupy entire rooms and look pretty similar to regular server racks.
LinuxONE Emperor 4 is a ready made machine for a hybrid cloud environemnt, it uses similar hardware components to the z16 mainframe making it possible to take advantage of features like AI nad quantum safe crypto. It was measured to reduce the CO2e footprint by 75% each year compared to an x86 system running linux.

While IBM Z mainframes can be configured to provide on-site cloud-like attributes relating to resource self-provisioning, pooling and scalability, some of the workload might also be sent off off-site onto the cloud, creating a hybrid environment.

Mainframe systems are used to host the most important, mission-critical applications. For example ATM transactions, direct debits, automatic payments, as well as payroll and compliance applications will likely all be on the mainframe system.

There are many roles required for proper operation of a mainframe system.