Virtual Operating system is the system which hosts the other operating systems. The real operating system requires a compiler, linker, editor such utility like programs. It also uses command language and operating system primitives. The virtual OS provides these services to the guest OS along with management platform, office information environment, program development platform and much more.

The idea of a virtual operating system is to provide standard versions of the following-

1. Programming languages used to access operating system primitives

2. The utility programs like compilers, linkers and editors

3. The command language by which users access system resources from a terminal based on organizational requirements

Virtual Memory

By using virtual memory, we can run the multiple processes though actual memory size. The processes that are running currently are placed in the memory while others are stored in the disk. The part of the process which must be in the memory to run is called its working set. A program doesn't need to have a whole binary file into the memory to run. e.g. if we want to run the program of 16MB and our memory size is 4MB then also we can run it easily.

Virtual Machine

A virtual machine is a guest operating system which is isolated from a normal host operating system but installation is done within a host operating system. Virtual Machine Operating System creates the illusion of multiple processors are executing independently. Virtual machines are separated into two major categories, based on their use and degree of correspondence to any real machine.

System virtual machines

System virtual machine creates an environment where multiple operating systems can execute on the same computer. The magical thing is that these all operating systems are isolated from each other. The processes don't know what other processes are doing. The figure below shows the working of the virtual operating system.

Working Of Virtual Machine OS

A virtual machine architecture is given in the layered form. The bottom-most layer is host hardware. All the hardware related to inputs and outputs belongs to this layer. Host operating system makes an elegant and convenient base upon which to build and run a VMM such as UMLinux. Each virtual hardware component maps naturally to an abstraction in the host OS, and the administrator can interact conveniently with the guest-machine process just as it does with other host processes. However, while a host OS provides sufficient functionality to support a VMM, it does not provide the primitives needed to support a VMM efficiently.

A virtual-machine monitor is a software layer that runs on a host platform and provides an abstraction of a complete computer system to higher-level software. The software running above the virtual-machine abstraction is called guest software (operating system and applications).