The basic idea behind a virtual machine is to remove the hardware from a single computer and make it a self-contained operating environment that behaves as if it it was a separate computer. Essentially, virtual machine is software that runs an application and isolates it from the actual operating system and hardware. CPU scheduling and virtual memory techniques are used so that an operating system can create the illusion that a process has its own processor with its own (virtual) memory. The virtual machine provides the ability to share the same hardware while running several different operating systems simultaneously. Virtual machine conceptSay no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get an original essay A major difficulty with the virtual machine concerns disk systems. For example, the physical machine has two disk drives but wants to support five virtual machines. The physical machine is not able to assign a disk drive to each virtual machine because the virtual machine software itself will need significant disk space to provide virtual memory and queuing. waiting. To resolve this dilemma, virtual disks identical in all respects except size are provided. The system implements each virtual disk by allocating as many tracks on the physical disks as the virtual disk needs. Virtual machine implementation is difficult. A lot of work is required to provide an exact copy of the underlying machine, which has both user mode and kernel mode. The virtual machine software can run in kernel mode since this is the operating system, where the virtual machine itself can only run in user mode. In a virtual machine implementation, there must be a virtual user mode and a virtual kernel mode, both of which run in physical user mode. Operations that cause a transfer from user mode to kernel mode on the physical machine must also cause a transfer. from virtual user mode to virtual kernel mode on a virtual machine. The virtual machine concept has several advantages. In this environment, different system resources benefit from complete protection. Each virtual machine is completely isolated from all other virtual machines, so there are no protection issues because there is no sharing of resources. Two approaches were implemented to ensure sharing. First, it is possible to share a virtual disk to share files. This is modeled after a software-implemented shared physical disk. Second, it is possible to define a network of virtual machines, with each virtual machine sending information across the virtual network. This is modeled after physical networks, but is implemented in software. The virtual machine system is perfect for operating system research and development. Generally, changing operating systems is a difficult and time-consuming task. Indeed, operating systems are quite large and complex programs and it is difficult to guarantee that a change in one part of the system will not cause problems (or bugs) in another part of the system. The complexity and power of the operating system makes modifying it dangerous because the operating system runs in kernel mode. Therefore, a wrong modification could cause an error that could destroy the entire file system. This is why.