Explore the process of porting Go to the IBM z Architecture in this GopherCon 2016 talk by Bill O'Farrell. Dive into the world of mainframes, understanding their modern relevance and the importance of Go in this environment. Learn about the technical challenges faced during the porting process, including writing assembler for z architecture and adding relocation to the linker. Examine code examples and optimizations, with a focus on cryptographic implementations such as AES and CBC. Discover the significant performance improvements achieved, particularly in the crypto package, and gain insights into future developments for Go on mainframe systems.