I've been seeing a lot of talk about virtual machines of late. From what I've read it is some sort of software environment that can trick software into thinking it has full control of the machine's hardware, making it possible to run programs that require full control of a device that is already locked down by another process.

Is this correct, and if so, what is it that people are doing with it?

Why am I hearing so much about virtual machines all of a sudden?

What are some of the uses/advantages?

Thanks,
Macele

Well... not really.

A virtual machine is just that. It's a virtual machine. It's a computer that doesn't exist. That is, it is a software emulation of an entirely separate hardware computer. So I can have an x86 virtual machine on my Sparc workstation. It can sometimes be used to give a process fake root permissions. Well, I guess they are real root permissions, but on a non-existent machine. However, a user on a (real) computer can only give the virtual machine access to hardware that the user itself has access to. So it's not a silver bullet for solving hardware locking or IO scheduling problems.

They are mostly being used for very high-security or high-availability applications. In other words, if I run a server, and I know that apache crashes more often than everything else because it's attacked more often, I run it in a virtual machine. Then, even if malware/a cracker manages to bring down the entire machine, all they take down is a virtual machine that I can just restart. They are also used when you need to run multiple operating systems simultaneously, usually when someone gets an itch for a Windows-only game.