"Mainframe systems" refers to large and powerful computers used by organizations to store and process immense amounts of data. They are known for their reliability, security, and ability to handle multiple tasks simultaneously. Full definition
Monitoring Mainframe system performance and availability and maintaining a working knowledge of system commands and subsystem configurations (jobhero.com)
More than three years of professional experience in testing mainframe system application and performance (bestsampleresume.com)
Over thirty years of experience as a Computer Operator and Operations / Production Support Analyst on Large IBM z / OS, VM and similar MVS Mainframe Systems. (members.climber.com)