Rosalind Radcliffe presented on shifting mainframe software development left to enable continuous integration. She discussed how mainframe applications today rely on outdated development and testing practices. Radcliffe proposed automating deployment of test environments, refactoring applications into services, implementing interface testing using virtual services, integrating production monitoring into development, and using operations data to optimize applications. Case studies showed how financial institutions reduced testing time from weeks to hours and increased test coverage through these practices. Radcliffe's goal is to modernize mainframe development and establish metrics to prove automated testing can replace manual regression testing.