MVS, which stands for Multiple Virtual Storage, is one of the oldest operating systems developed by IBM and distant relative to what we nowadays call DOS. MVS has its own 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 programmers still use JCL on a daily basis in the 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 is still king.

The following table shows the history of MVS. The information below was taken from the book Understanding Operating Systems by Ida Flynn and the IBM website.

Most people do not have access to a mainframe. You can run Hercules, which emulates a mainframe environment on your computer. A previous installation of Cygwin is needed for Windows.