Hercules is an open source software implementation of the mainframe System/370 and ESA/390 architectures, in addition to the new 64-bit z/Architecture. Hercules runs under Linux, Windows, Solaris, FreeBSD, and Mac OS X.
Hercules was created by Roger Bowler and is maintained by Jay Maynard. Jan Jaeger designed and implemented many of the advanced features of Hercules, including dynamic reconfiguration, integrated console, interpretive execution and z/Architecture support. A dedicated crew of programmers is constantly at work implementing new features and fixing bugs.