The term virtualization has many meanings, and aspects of virtualization permeate all aspects of computing. Virtual machines are one instance of this trend. Generally, with a virtual machine, guest operating systems and applications run in an environment that appears to them to be native hardware and that behaves toward them as native hardware would but that also protects, manages, and limits them.
10.1 VIRTUAL MACHINES
The fundamental idea behind a virtual machine is to abstract the hardware of a single computer (the CPU, memory, disk drives, network interface cards, and so forth) into several different execution environments, thereby creating the illusion that each separate environment is running on its own private computer. This concept may seem similar to the layered approach of operating system implementation.
10.2 OPERATING SYSTEMS OF VIRTUAL MACHINES
Operating systems of virtual reality are usually a combination of traditional operating software and features that support virtual reality, usually networking algorithms. One example is the daydream by Google. Daydream is a virtual reality (VR) platform developed by Google that is built into the Android mobile operating system (versions "Nougat" 7.1 and later). Compatible phones that follow the platform's software and hardware specifications (and are thus designated "Daydream-ready") are used in the Google Daydream View VR headset. The Daydream platform was announced at the Google I/O developer conference in May 2016, with the first VR headset released on November 10, 2016. Daydream is the company's second VR platform following Google Cardboard, which was a low-cost system intended to encourage interest in VR and was built into compatible mobile apps rather than the operating system itself.