I’m trying to understand them a bit better, but it’s just not clicking for me. How is it able to operate like a physical computer and what is the benefit of that? Would you be able to say write an essay for your English class on a VM, save it there, and access it at a later time?
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Your physical computer sends instructions to a processor, memory, and storage devices to do the things that you expect it to do. A virtual computer is just another layer of software that pretends to be the same components in your physical computer such that you can install an operating system on it. So yes, you could install Windows, Office, write an essay, and email it to yourself.
All an operating system is is an interface between your applications and the hardware; that these days provides some convenience functionality: a shell/desktop environment, a file system for data storage. But at a low level, the operating system is just computer code itself running in the CPU of the computer.
But what’s the difference between a computer instruction running on the real hardware CPU or one that is interpreted by a software based CPU that is itself running on a real CPU? Turns out, not much.
When you turn on a computer, the CPU knows to look in one specific location for its very first instruction. These instructions are a boot loader. These point to other locations to load special operating system files (for Windows or Linux). So you could easily write a program that emulates or simulates a CPU in this behaviour… you can write software the emulates _everything_ in a computer.
That’s all that virtualization is – an emulated computer running on a special virtualization platform that is running on a real computer.
To answer your question about the essay tho… the answer is: it depends. When you write your essay and hit save, the essay is written to a physical hard disk or storage device. IN a virtual machine, the essay would be saved to a virtual hard disk/storage device, which itself is just a special file on the real storage that the virtualization software can understand. So yes, so long as they physical hardware that stores the virtual machine is ok, then yes you should be able to access the virtual storage as well.
The nice thing about virtual machines is you can save their state at any time and restore back to it. We use virtualization at work in our testing all the time. We have a virtualized Windows PC, we install our software, the software was buggy, causes the virtual computer to crash, we wipe/restore the VM back to its known good state with a single instruction.
Old MS-DOS game emulators like DOSBOX? essentially these are virtual machines. Playstation or Gameboy emulators? virtual machines. Someone has just taken the time to write software that emulates the hardware of these old platforms.
Computer operating systems are software working in tandem with hardware. Virtual machines run that same OS software from something called the Hypervisor, which is in part like a hardware emulator, and virtual computer manager.
While you can create storage locations in virtual machines, those locations are typically accessible to both the virtual machine and the machine that runs the virtual computer.
A benefit to VMs from a personal standpoint is that you can do most anything in the virtual machine without fear of irreparable harm to the host computer: like if you’re examining a file for viruses it can be far safer to engage with the file from within the VM. You can run applications that only run well in Windows 98, for example, by having a W98VM.
From the corporate perspective, VMs can increase productivity and drastically cut hardware costs. Instead of a thousand high-performing desktop computers, you can setup a high-performing server/storage array and setup users with thin or zero-clients, which are purpose built hardware to connect to virtual machines. It doesn’t take a lot of horsepower to engage with a remote server and stream video of what you should be seeing on your desktop, uploading your keyboard/mouse/etc input.
A VM is just a program run on the host OS (operating system) providing all the functions that the hardware would normally provide to the guest OS. It can also create “virtual hardware”, like a fake disc drive that can load iso files from the filesystem. So if an OS would normally ask for a file to be moved from point A to point B, a guest OS would ask the VM software to move the file, and then the host OS would tell the hardware to perform that task.
The benefits of a VM is that you can (partially) isolate the hardware from the OS and do fun things like running multiple OSes (with multiple VMs) at the same time. You can also use the same source image of a VM to recreate the same virtual server whenever you need it, such as if you need to rapidly scale up your server network or your old server died or got corrupted.
Virtual computers are used a lot. If you want to get started you can try installing a different Windows version or a Linux distribution just to try it out without changing anything in your regular OS. If you want to use some software package but you don’t want to install it as it comes with a lot of crap, install it on a VM and delete it when you’re done. Make a new VM you only use for online banking if you fear spyware or viruses. Want to try running a Minecraft server? Practice on a VM! Ruin the install? Roll back to a snapshot you took earlier. Have a game that only works on Windows XP? Run XP on a VM and game on that.
try it this way. a virtual machine is a program that runs on your machine and pretends to be another machine.
yes, a virtual machine can run another virtual machine inside it. i think statistically that means every machine is a virtual machine or something (sorry simulation hypothesis guys).
virtual machines are optimised to run fast enough that they’re almost as fast as your physical machine. so you can certainly browse the web and write documents. sometimes you can even play triple A games on them.
you can rent a virtual machine from Amazon, it runs on their servers and you can use it for pretty much whatever you want.
another kind of virtual machine is an emulator. these are programs that pretend to be other kinds of machines, like old 8 bit systems or games consoles.
common virtual machines are: vmware, virtualbox, hyper-v, amazon web services, microsoft azure, linode.
if you want to try out other operating systems, it’s often a good idea to make a virtual machine and install it on there. that way you don’t risk anything on your main machine.
The whole point of virtual machines is to utilize hardware better. Let’s say you have an office and you want a file server. You buy a server with a CPU, RAM and storage, you install Windows Server on it and configure it for file storage.
So far so good. The server is barely doing anything, it just sits there idling 99% of the time but that’s ok.
Now Steve in Accounting and Mary at the frontdesk both want to have their own printers on their desks. Other employees want to use those too.
So you buy a second server, plug it in, boot it up. install Windows Server and configure it as a print server. Sweet.
Remember Steve in accounting? He would like some cool intranet page to display his spiffy graphs on, for everyone to see.
So off to BestBuy you go to buy a third server. You find an extra powerstrip, you plug it in, install it, configure it as webserver and everyone is happy.
Congrats. You now have three servers all doing pretty much nothing 24/7. But what if….what if you used one physical server, and then built three virtual servers on it. Those virtual servers all have their own operating system, their own IP adress and everything and appear to the outside world as an individual server. But in reality it’s all just running on one physical box. It’s a lot cheaper (less hardware), and the hardware is much better utilized.
This is a very simple little sketch to give you an idea. It doesn’t go into the cooler details like the fact virtual machines are for a big part hardware independent, so you can fail-over all virtual servers to a different physical box, in case the host suddenly has a hardware failure for instance.
VM’s: they are cool stuff and big parts of the world are running on them.
VM is just another computer running inside another computer.
The host for a VM is always a physical computer/server. Running somewhere in a datacenter, or even in your own home.
The benefits of VM’s in a regular consumer use are little to 0 (Think: I use my pc to game a bit, browse the internet, maybe read or write documents). Businesses, education systems on the other hand can benefit from them greatly.
E: If you want to flexibly write/save/read on multiple devices, you wouldn’t need a virtual machine for that. You could use a Google Drive, OneDrive and other cloud services for files.
A Virtual Machine(VM) is just an emulator for a PC. Most emulators you run on your computer you use to emulate other things like a Gameboy or N64 or Atari, but there’s no reason one can’t pretend to be a fully functional PC
VMs are used because they’re little containers. A program running in VM1 cannot interact with something in VM2, their memories are separated, and importantly they can’t change anything on the physical machine they’re running on. If you need to test a sketchy program to see if its actually a virus you can do this in a virtual machine, and if it tries to write somewhere its not supposed to, like the ROM on your hard disk that controls it, it’ll instead write to a fake memory location in the VM, and you can just nuke the VM with minimal risk to the actual machine and the rest of the data on it.
Most web servers are running tons of VMs. A powerful AWS server can be hosting a VM that runs a chunk of Netflix, and another that has a chunk of Reddit, and another that has a chunk of Amazon Video but none of them can tell the other exists on the same machine and they can’t interact with each other.
A common Virtual machine (probably less so now) was DosBox which basically created a VM of an older PC running MS-DOS so you could emulate and play older DOS games that were expecting a CPU at 66 MHz and don’t really know what to do when one reports 4 GHz, so you instead emulate a 66 MHz CPU and a reasonable amount of memory so things don’t get wild
Yes you can do that if you wanted to. Simply put, it’s a computer running in a computer.
There’s a few advantages:
Server infrastructure – Everything in AWS/Azure runs on VMs. It makes it easier to manage huge amounts of servers. If one goes down, you can restart a VM on another physical box without losing any data.
Security – This is becoming more important. Separate VMs typically cannot interfere with another VM or access their data. A lot of modern computers are taking this strategy to keep your device secure. This is also known as sandboxing
Where you use them and probably don’t realize it: The XBox consoles run games as VMs. The entire internet. Some computers (eg the Surface Book line of devices) run the OS as a VM and use a more secure OS running on top of it.
On your suggested use, some journalists actually use something similar to this to protect themselves and their sources. They might use a VM (or similar strategy) in order to hold and store really sensitive information and articles to prevent it from being hacked or tracked.
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