What is MVS?
MVS, which stands for Multiple Virtual Storage, is one of the oldest operating systems developed by IBM and distant relative of what we nowadays call DOS. MVS has its own programming language, JCL (Job Control Language). Three decades after MVS was created (1974), JCL is still heavily used. As a matter of fact, where I work some programmer still use JCL on a daily basis in the IBM z/VM system. Some of the applications where I work query VSAM files and third-party application handle screen scraping to replicate the screens and output to ASP or JSP. After over forty years, the mainframe computers are still king.