CAMBRIDGE – COMPUTING 9608 - GCE A2
SYSTEM SOFTWARE 1
3.4 SYSTEM SOFTWARE
3.4.2 VIRTUAL MACHINE
INTRODUCTION
A virtual machine is a software computer that, like a physical computer, runs an Operating System
and various applications.
Virtual machines allow you to run an operating system in a window on your desktop. A virtual
machines could be used to run software made for other operating systems. For example, running a
program built for Ubuntu on your Windows 8 computer. The virtual machine runs in a window on
your main operating system.
WHAT IS A VIRTUAL MACHINE?
A virtual machine program is a computer program that creates a virtual computer system, complete
with virtual hardware devices. This virtual computer “machine” runs as a process in a window on
your current operating system. You can boot an operating system installer disc inside the virtual
machine, and the operating system will be “tricked” into thinking it’s running on a real computer
allowing you to install different operating systems on your virtual machine.
Your virtual machine’s operating system is stored on a virtual hard drive – a big, multi-gigabyte file
stored on your Hard Drive. The file is presented to the operating system as a real hard drive.
Virtual machines add some overhead, so they won’t be as fast as if you had installed the operating
system on real hardware. Demanding games that require serious graphics and CPU power are one
particular problem, so virtual machines aren’t the ideal way to Windows games on Linux or Mac OS
X – not unless those games are much older or aren’t graphically demanding. Also, when multiple
virtual machines are simultaneously running on a host computer, each virtual machine may hang;
this also depends on the workload on the system by other running virtual machines.
WHY YOU’D WANT TO CREATE A VIRTUAL MACHINE
Virtual machines allow you to experiment with another operating system without leaving your
current OS. A virtual machine is also a great way to test out a new version of Windows. When the
