Virtual Machines in Operating system

The fundamental idea behind a virtual machine is to abstract the hardware of a single computer like the CPU memory disk drives network interface cards and so forth into several different execution environments thereby creating the illusion that each separate execution environment is running its own private computer alright so here we have a long definition.
Now let us try to break this definition down and try to understand what this virtual machines actually means so here it says the fundamental idea is to abstract the hardware of a single computer so we have a single computer on which it has its Hardware resources like the CPU the memory the disk drives the network interface cards and so on so we are going to abstract the hardware of this single computer into several different execution environments and hence what happens we create the illusion that each separate execution environment is running its own private computer so we take the Hardware of a single computer and we give it to several different execution environments and we create an illusion to that execution environment that they are running their own private computer.
So that is what we mean by virtual machines so the term virtual what does it mean means that it is not physically real but we try to make it look like it is something physically real so these days you must have come across virtual reality which is a very popular and common topic that is going on will you even have your virtual reality headsets in which what happens when you wear this virtual reality headset and when you watch some video you feel like you are physically in that video or you feel like it is physically happening around you but in reality, it is not actually physically happening but you are getting an illusion that it is physically happening so in the same way in case of operating systems this virtual machines also do something like that.
What it does is creates the illusion that each separate execution environment is running its own private computer while in reality, it is not, in reality, we are just on one computer having just the resources and hardware of that particular computer but we are creating an environment or an illusion that these different execution environments are running their own separate computers.
We are able to have three different kind of execution environments for this particular example that we have taken here so let’s say that you are having your hardware here in your physical system and on your system you are having Windows operating system installed let’s say that you are having your main Windows operating system installed then using this virtual machine implementation or using the virtual machine software you have created three virtual machines virtual machine 1 2 & 3 & our virtual machine 1 let’s say that you have installed Linux Mint operating system and on virtual machine 2 you have installed another distribution of Ubuntu operating system and in virtual machine 3 also you have installed let’s say fedora or some other Ubuntu distribution operating system so we see that at the base we are having this Hardware on which we have the Windows operating system and by the help of this virtual machines you have installed 3 operating systems on your computer now for a particular operating system let’s say that here you are having Linux Mint for this lensman it looks like or it feels like it is running its own private computer so it doesn’t have to know that it is a virtual machine or what it is it just feels like it is running its own private computer and so is the same for the other two operating system that you have installed over here so we are creating an illusion that each separate execution environment is running its own private computer so that is the main fundamental idea behind a virtual machine implementation.
Now let’s take a deeper look at the implementation of the virtual machine system now we know that there are two modes of operation that we have already studied about before which is a user mode and kernel mode now we need to find out how does a virtual machine actually run so does it run in user mode or the kernel mode so first of all the virtual machines software that runs in kernel mode the virtual machine software which allows the implementation of virtual machine that is the base operating system that you have so that one it runs in kernel mode but the virtual machine itself it runs in the user mode the virtual machine itself means these virtual machines that we have over here they run in DES user mode and when I talk about kernel mode and user mode over here I’m talking about the real or the physical kernel mode and user mode that we have in this system all right so the virtual machine software which is the operating system itself on which you are installing these virtual machines that runs in kernel mode but the virtual machine itself that means these virtual machines VM one VM to VM three they run in the user mode of the physical system now the question is that here we have this virtual machine with its own kernel and processes and we have already said that virtual machine runs in such a way that that execution environment is operating its own private computer so if this is in the illusion that it is operating its own private computer it also needs to have a user mode and kernel mode for its operation.

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