http://www.jaymoseley.com/hercules/ Hercules an IBM S/370 and ESA/390 Emulator than runs on Intel architecture. Of course it needs an operating system. Some of the older MVS, MVT, VM 370 R6 operating systems are in the public domain, but not the manuals. (Interesting that they are in the public domain perhaps they were not copyrighted at that time because it was believed that software was not copyrightable/patentable?