From hercules-390 FAQ (which I was a developer long ago). OS/390, z/OS, and other ESA or z/Architecture operating systems are definitely licensed to a particul

From hercules-390 FAQ (which I was a developer long ago). OS/390, z/OS, and other ESA or z/Architecture operating systems are definitely licensed to a particular machine. Therefore, in practice you cannot run any classic ESA or z/Architecture operating system on your PC unless you can obtain a license from IBM allowing you to do so. It is believed that there are, however, four ways you could run z/OS, z/VM, z/VSE, OS/390, VM/ESA, or VSE/ESA under Hercules using currently available licenses: 1. Running under Linux on the Pentium processor of a P/390 which is licensed to run the OS. 2. Running under Linux/390 on a mainframe which is licensed to run the OS. 3. Running under the terms of a disaster recovery provision of the OS license (but I really don't recommend depending on Hercules to be your disaster recovery solution!). 4. Using the IBM OS/390 or z/OS DemoPkg, which is available only to IBM employees and IBM Business Partners