Editing Conversational Monitor System (section)

==Architecture==
CMS is an intrinsic part of the VM/CMS architecture, established with [[CP/CMS]]. Each CMS user has control over a private [[virtual machine]] &ndash; a simulated copy of the underlying physical computer &ndash; in which CMS runs as a stand-alone operating system. This approach has remained consistent through the years, and is based on:
* [[Full virtualization]], used to create multiple independent virtual machines that each completely simulate the underlying hardware
* [[Paravirtualization]], used to provide a [[hypervisor]] interface that CMS uses to access VM services; this is implemented by the non-virtualized DIAG (diagnose) instruction

More details on how CMS interacts with the virtual machine environment can be found in the [[VM (operating system)|VM]] and [[CP/CMS]] articles.

CMS was originally built as a stand-alone operating system, capable of running on a [[bare machine]] (though of course nobody would choose to do so). However, CMS can no longer run outside the VM environment, which provides the [[hypervisor]] interface needed for various critical functions.