Virtual Machines Tyldesley
If you've ever fancied dabbling with Linux or wanted to try out the free beta versions of Windows Vista that Microsoft recently made available, a second, spare PC is the safest option.
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Virtual Machines
If you've ever fancied dabbling with Linux or wanted to try out the free beta versions of Windows Vista that Microsoft recently made available, a second, spare PC is the safest option. The same is true if you need to install an earlier version of Windows to use a particular program that won't run under Windows XP, or just need access to those older operating systems for other purposes.
You can set up your PC to 'dual boot', giving you the choice of an operating system to use whenever you switch on. This isn't without its risks though, and it's a chore to reboot your PC whenever you want to use a different operating system or program. But what if you could run the operating system of your choice within a window on your Desktop? This is just what virtualisation offers.
Once a highly specialised and costly business, virtualisation is now within the reach of everyone, thanks to software from the likes of Microsoft or VMware. One free small download later and you can install the operating system of your choice within an 'emulated' PC running on your Desktop, which means access to Linux and any version of Windows is just a couple of clicks away.
Overview
Virtualisation lets you run an operating system on your PC just as you would any other program. The operating system isn't running directly on your hardware. Instead, it runs on hardware that's being emulated by virtualisation software. The operating system and the programs it runs are none the wiser, but the resulting virtual PC is self-contained within a single file on your PC and poses no risk to your other files - even the worst blue screen, hard disk-trashing crash is contained within the emulated PC. It's a bit like living in The Matrix - everything looks and behaves like the real thing, but it's all a computer simulation and nothing that happens inside it affects the real world.
Everything inside a virtual PC is emulated - the processor, memory, hard disk and so on. You use a virtual PC just as you would a real one - start one for the first time and it's useless until you install an operating system, and then you'll need to install any programs you want to use. The virtual PC can access the internet and you can even copy files back and forth from your actual computer, making it ideal for testing software that you wouldn't let near your own PC with a barge pole.
Limitations
There are limitations, though. Emulating a PC in software is hard work and you'll need a computer with a reasonable specification to run a virtual PC at a usable speed. You can run just about any program on a virtual PC, but forget those that require 3D graphics - emulating a 3D graphics card in software is just too demanding and virtualisation software only provides very basic 3D support.
Memory is a vital factor too. The more memory your computer has, the more memory you can assign to a virtual PC, and all computers - virtual or otherwise - benefit from having lots of RAM.
We've taken a look at the three biggest virtualisation programs currently available in this feature. Two are free - Microsoft Virtual PC and VMWare Server - and Parallels for Windows is a paid-for program. They all let you run a wide variety of operating systems in a window on your Desktop, so read on to find out which we recommend.
Getting started
A virtual PC doesn't require its own hard drive or partition, but the first step in any virtual PC setup is to create a virtual hard disk for an operating system to run on. This is essentially a file that's the same size as the disk being emulated and most virtualisation software offers the option of a dynamically-sized disk that grows as more disk space is required. Most software also asks for an intended operation system, although this is usually only to pre-configure a few settings to give the best results. Virtual PC memory is 'borrowed' from your PC's memory, so you can't allocate more than you have. If you need to run other software at the same time, be sure to leave enough memory available for it to be able to function properly.
The final step is to 'turn on' the virtual PC, which results in a window that shows the usual white text on a black background that appears when you boot any computer. Since there's no operating system installed, this is as far as you'll get until you insert a operating system install CD or point the virtual PC at a CD image stored on your actual computer.
Virtualisation software
If you have never used virtualisation software, it can be hard to imagine just how it can be useful. One of the most common uses of such environments is to create a test computer. Fans of beta software will be aware that early versions of programs can be riddled with bugs that can cause countless problems. If you fancy giving a program a test drive, but don't want to risk your main Windows installation, why not install the software to a virtual one? This gives you the opportunity to try out the software risk-free before deciding whether you should install it on your main PC.
In the same vein, there are some programs that are not compatible with Windows XP and if you use such a program, you may begrudge having to set up a dual-boot system between XP and an older version of Windows. Using virtual PCs, you can install legacy Windows applications within XP and continue to use them as normal.
Similarly, maybe you've thought about trying out a new operating system - perhaps the beta version of Vista or a new Linux distribution? Installing such operating systems in a test environment allows you to try things out without the risk of damaging your PC or losing data. Programmers who need to test their software in a variety of operating systems can install everything they need to a single PC, and run their software in different environment while still having access to the tools they need in Windows.
Virtual PCs can also be useful if you need to produce software tutorials as it's possible to take screenshots without having to worry about clearing icon clutter off the Desktop. Another advantage is that it is possible to save their state. This means you can stop working in the middle of something, save your current progress and return to it at a later time, even turning off your computer in the meantime.
Conclusion
Virtualisation may seem a strange concept, but it has numerous applications. There are limitations, mainly down to running two operating systems at the same time and the limits on the range of hardware devices that can be emulated. While it is not currently possible to emulate specific individual components, the generic drivers included with virtual PC software make it possible to closely mimic the operation of a second PC.
You can set up your PC to 'dual boot', giving you the choice of an operating system to use whenever you switch on. This isn't without its risks though, and it's a chore to reboot your PC whenever you want to use a different operating system or program. But what if you could run the operating system of your choice within a window on your Desktop? This is just what virtualisation offers.
Once a highly specialised and costly business, virtualisation is now within the reach of everyone, thanks to software from the likes of Microsoft or VMware. One free small download later and you can install the operating system of your choice within an 'emulated' PC running on your Desktop, which means access to Linux and any version of Windows is just a couple of clicks away.
Overview
Virtualisation lets you run an operating system on your PC just as you would any other program. The operating system isn't running directly on your hardware. Instead, it runs on hardware that's being emulated by virtualisation software. The operating system and the programs it runs are none the wiser, but the resulting virtual PC is self-contained within a single file on your PC and poses no risk to your other files - even the worst blue screen, hard disk-trashing crash is contained within the emulated PC. It's a bit like living in The Matrix - everything looks and behaves like the real thing, but it's all a computer simulation and nothing that happens inside it affects the real world.
Everything inside a virtual PC is emulated - the processor, memory, hard disk and so on. You use a virtual PC just as you would a real one - start one for the first time and it's useless until you install an operating system, and then you'll need to install any programs you want to use. The virtual PC can access the internet and you can even copy files back and forth from your actual computer, making it ideal for testing software that you wouldn't let near your own PC with a barge pole.
Limitations
There are limitations, though. Emulating a PC in software is hard work and you'll need a computer with a reasonable specification to run a virtual PC at a usable speed. You can run just about any program on a virtual PC, but forget those that require 3D graphics - emulating a 3D graphics card in software is just too demanding and virtualisation software only provides very basic 3D support.
Memory is a vital factor too. The more memory your computer has, the more memory you can assign to a virtual PC, and all computers - virtual or otherwise - benefit from having lots of RAM.
We've taken a look at the three biggest virtualisation programs currently available in this feature. Two are free - Microsoft Virtual PC and VMWare Server - and Parallels for Windows is a paid-for program. They all let you run a wide variety of operating systems in a window on your Desktop, so read on to find out which we recommend.
Getting started
A virtual PC doesn't require its own hard drive or partition, but the first step in any virtual PC setup is to create a virtual hard disk for an operating system to run on. This is essentially a file that's the same size as the disk being emulated and most virtualisation software offers the option of a dynamically-sized disk that grows as more disk space is required. Most software also asks for an intended operation system, although this is usually only to pre-configure a few settings to give the best results. Virtual PC memory is 'borrowed' from your PC's memory, so you can't allocate more than you have. If you need to run other software at the same time, be sure to leave enough memory available for it to be able to function properly.
The final step is to 'turn on' the virtual PC, which results in a window that shows the usual white text on a black background that appears when you boot any computer. Since there's no operating system installed, this is as far as you'll get until you insert a operating system install CD or point the virtual PC at a CD image stored on your actual computer.
Virtualisation software
If you have never used virtualisation software, it can be hard to imagine just how it can be useful. One of the most common uses of such environments is to create a test computer. Fans of beta software will be aware that early versions of programs can be riddled with bugs that can cause countless problems. If you fancy giving a program a test drive, but don't want to risk your main Windows installation, why not install the software to a virtual one? This gives you the opportunity to try out the software risk-free before deciding whether you should install it on your main PC.
In the same vein, there are some programs that are not compatible with Windows XP and if you use such a program, you may begrudge having to set up a dual-boot system between XP and an older version of Windows. Using virtual PCs, you can install legacy Windows applications within XP and continue to use them as normal.
Similarly, maybe you've thought about trying out a new operating system - perhaps the beta version of Vista or a new Linux distribution? Installing such operating systems in a test environment allows you to try things out without the risk of damaging your PC or losing data. Programmers who need to test their software in a variety of operating systems can install everything they need to a single PC, and run their software in different environment while still having access to the tools they need in Windows.
Virtual PCs can also be useful if you need to produce software tutorials as it's possible to take screenshots without having to worry about clearing icon clutter off the Desktop. Another advantage is that it is possible to save their state. This means you can stop working in the middle of something, save your current progress and return to it at a later time, even turning off your computer in the meantime.
Conclusion
Virtualisation may seem a strange concept, but it has numerous applications. There are limitations, mainly down to running two operating systems at the same time and the limits on the range of hardware devices that can be emulated. While it is not currently possible to emulate specific individual components, the generic drivers included with virtual PC software make it possible to closely mimic the operation of a second PC.
Author: Mark Wilson
