Unisys
Unisys is another vendor of mainframe solutions. Unlike IBM, they do offer "home lab" use of their mainframe OSes to encourage experimentation and personal development at no cost, and fairly good documentation.
ClearPath MCP[edit | edit source]
ClearPath MCP Express is free to use for non-production hobbyist use, only requiring you re-license the OS every year on July 31st.
Unisys offers not only fairly good documentation but video tutorials on setting up the environment.
ClearPath OS2200[edit | edit source]
Like MCP, OS2200 Express is a free hobbyist version of the ClearPath Forward OS2200 platform.