Virtual Machine

A Virtual Machine is one of the coolest things in computer science, without getting into complicated details, it is like having a "Virtual" computer "inside" your own real computer...

This is VMware Workstation, a program that allows you to run many "Virtual Machines", in this case, VMware Workstation is installed on a Windows Vista computer (called the host), and is running ubuntu as a guest

This is VirtualBox, and in this case ubuntu is the host and is running Fedora as a guest

How does it work?

A Virtual Machine creates a virtual environment for the operating systems to run, isolated from the real operating system in the host computer, so all the problems/virus/Blue screens that may affect the guest will not affect the host (at least in theory!)

What is a Virtual Machine usefull for?

• Trying many Operating Systems without having to format or re-partition your Hard Drive, and with no risk of breaking your "real" system...
• Run older versions of Operating Systems, for example, lets say you have a computer with Windows Vista installed, and you need to run some older software that only supports windows 2000 or XP... the solution? just create a Virtual Machine with Windows 2000 (or XP), and then run the old program "inside" the Virtual Machine!
• Testing many software without installing it on a real computer
• Running/testing Live CDs and Live USBs
• Many other cool stuff!

Current limitations of this type of Software

• Since a Virtual Machine is an isolated environment, you can only acess some real hardware, wich does not include, for example, a built in wifi adapter (see note one for details)
• Support for 3D graphics inside the Virtual Machine is still somewhat experimental (as of 2011)

Notes

1. VMware Workstation can connect some (real) Hardware to a Virtual Machine, being at the moment: USB devices, CD/DVD drives, floppy drives, Hard Drives, SCSI devices and devices that use a serial or parallel port

Examples of Virtual Machine Software

1. VMware Workstation
2. VirtualBox