Here are the highlights:
VM/370

The VM/370 "SixPack" version 1.0 rolls up all of the modifications posted on the H390-VM and Hercules-os380 Yahoo groups since the "5-pack" system was released in 2006.
 
The base operating system is IBM's VM/370 Release 6 operating system, the last unlicensed version of VM/370. It is designed to run on the Hercules Emulator.
 
New features of the "SixPack" include:

• An up-to-date, accurate, and fairly complete help system.

• The Gnu C Compiler, with both a "traditional" runtime library (PDPCLIB) and a "native CMS" runtime library (GCCLIB). Type HELP GCC for information on compiling C programs.

• Extended parameter list support, meaning it is possible to pass mixed-case parameters to EXECs and C programs.

• Current line highlighting and multifile editing in EDIT.

• Other programs such as DIFF, FLIST, RESLIB, SCAN, VMARC are all available on the CMS Y disk.

This version of VM/370 is brought to you by Robert O'Hara, Paul Edwards, and Dave Wade. It is based on earlier versions of VM/370 for Hercules developed by Andy Norrie and Paul Gorlinsky.
 
All this available here:
http://www.open-bpm.org/index.php/mainframes.html
Free registration required