Hypervisor

A hypervisor, or a "virtual machine manager" or "monitor" (VMM), is a program that allows multiple operating systems to share a single "host" computer. The hypervisor allocates resources from the host to the virtual machine(s) so that each "guest" operating system can behave as though it had the host's processor, memory, and other resources all to itself.

Types

 * A "Type 1" hypervisor, also referred to as a "bare metal" or "native" hypervisor, runs directly on the computer hardware without the overhead of an host operating system. This is common in data center or server-based installations.
 * A "Type 2" hypervisor, also referred to as a "hosted" hypervisor, runs on a conventional computer setup with a host operating system. This is preferred for individual users who would like to run alternate operating systems on existing personal computer hardware. Options for macOS users, such as Parallels Desktop for Mac, VirtualBox, and VMware Fusion, would fall under this category.

Support by Apple
With the release of macOS 11 (Big Sur) in 2020, Apple began including a lightweight hypervisor framework directly in the macOS operating system for use by developers, with access to Rosetta 2 for emulation of Intel hardware on Apple Silicon-based systems. VirtualBuddy is a free open source hypervisor that supports this framework in macOS 12.3 (Monterey) or later to allow easier testing of beta versions of macOS from the Apple Developer program.