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What is a virtual machine?

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It is something I mentioned in the previous videos, but it is important for us to fully understand

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what it is.

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I can just give you a definition and say virtual machine is a machine within our physical computer that

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is using its hardware resources.

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But for most of you, this will be a new term that you haven't encountered before, so I would like

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to explain it further, more for you as well as mentioned, why are we going to use it?

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Let me start like this.

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All of us are running an operating system and ninety nine point nine percent of us are running one of

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the three main operating systems.

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You either have windows.

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Mac OS or Linux, most of you will have either Windows or Mac OS.

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I doubt anyone will be running Linux, but nonetheless, these are the three main ones.

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And what if we wanted to, for example, run two different operating systems on the same machine?

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For example, let's say you have windows installed on your machine and you want to install Linux or

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even better in case you want to install five operating systems running on different virtual machines.

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Can you do that?

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You can how would that work?

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Well, picture it like this.

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Imagine this rectangle representing our computer.

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And we already know that any computer will have one of the three main operating systems, Windows,

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Mac OS or Linux.

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But operating system is not the only thing that is defining our machine.

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Our machine also has its computer parts.

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We have hard disk processor, RAM memory motherboard and many more computer parts that with the operating

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system, make our machine work.

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These computer parts are also known as hardware.

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But wait a second, Alexa, why are you telling us this?

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Thought this was a lecture on explaining how machines work and not on hardware components.

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Hang on just a second.

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We're slowly getting there.

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Picture a virtual machine to build a smaller rectangle within our physical machine, which is this larger

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rectangle.

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And let's imagine that our physical machine is running Windows operating system.

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But if you took a look at this course content, you would notice that we're going to be doing all of

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our hacking stuff, mostly over Linux.

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Does that mean that we must delete our Windows and install Linux?

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No, we will install Linux as a virtual machine.

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And for this machine to work.

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It will need to have access to our hardware components.

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What does this mean?

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Well, since Virtual Machine will act as a machine of its own, it must have its own computer parts

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and what we will do is we're going to borrow our physical machine, CPU power, ram memory, hard disk

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memory to our virtual machine so it can run just like our physical machine.

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In other words, we are splitting the power of our physical machine into two different machines or more

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if we decide that we want to create multiple virtual machines.

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Does that mean that they will be slower since they will be splitting the resources?

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Well, technically, yes, but it will not be noticeable for us.

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However, the more powerful your PC is, more virtual machines, it will be able to run effectively.

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Another important thing is that once you shut down your virtual machine, all of the hardware resources

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used by it will get feedback for your physical machine to use.

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OK, good.

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And what are the other benefits that we have if we create a virtual machine?

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Well, since we are hackers and we will be doing a lot of things and running a lot of programs on that

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virtual machine, we want to make sure we are doing it first in a safe environment, at least while

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we learn.

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The good thing about virtual machines is that if, for example, our machine starts getting some annoying

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error or we get locked out of our files, or another case would be that we delete the file that we shouldn't

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have deleted and it crashes our virtual machine.

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What if we simply just get infected by a malware or virus by accident or another possible scenario would

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be that we just installed the wrong version of operating system, which we don't need.

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Will any of this present a problem?

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Don't worry, with two clicks, we can delete entire virtual machine, all of its files, and it will

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have no effect on our physical machine, then we can proceed to create a new one for as many times as

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we want.

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We can also create something called a snapshot, which will allow us to save the current state of a

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virtual machine, and with it we can reverted back to that state whenever we want.

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It can be useful if we, for example, ran into some error or we get infected with the virus, we can

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simply just reverted back and our virtual machine will act as none of that happened.

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Sounds cool, right?

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Now that we know how virtual machines work and why are we going to use one, you must be wondering how

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can we create a virtual machine?

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Actually, it is pretty easy.

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All we need are two things.

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We need an operating system that we want to install in that virtual machine.

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And we also need something called virtualization software.

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Now, what is that, even though it sounds harsh saying virtualization software, what it essentially

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is, is a program that will allow our physical machine to borrow hardware components to our virtual

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machine, or we can also define it as a program that will allow us to run multiple operating systems

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on a single host.

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So with these two, we can create our virtual machine and in the next few lectures, we're going to

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see exactly how we can do that.