Microsoft has been offering multiple virtualization systems,such as virtual backup. Some items come at no charge, and if you are new to virtualization you may want to find out which product is the right one for you.

The major players in this market are Microsoft and VMware. VMware was actually first and now offers its products for free as well.

Microsoft's Hyper-V backup platform recently gained a strong advantage over VMware in that it allows better live backups via Volume Shadow Service; therefore, for many experienced VM administrators, Microsoft may be the better choice.

Now, home users are given Virtual PC which runs from XP to Windows 7 and can be downloaded from Microsoft's website.

The VPC functionality is tiny but allows users under Windows 7 to run older apps directly on their desktop. Think about it, you are able to see an old XP program inside Windows 7 as a window. There is no need to use remote desktop or view the entire virtual machine in a separate window.

This is basically all that's new in virtual PC. Virtual Server provides a website-based control page where you can manage several VMs at the same time and also runs under x64, which isn't supported by Virtual PC.

However, one big dilemma with virtual PC as well as Virtual Server is their lack of multiple CPU core utilization. For quite a while VMware was the leader in this type of CPU emulation technology.

Microsoft has caught up with VMware and offers this functionality in Hyper-V.

In addition, another new feature in Hyper-V is that you can have a VM write to the host's hard drive directly and turn off the VHD mechanism. Hence you do not have to have VHD files at all and the disk read/write speeds are phenomenal.

Reading and writing directly to the disk is a major speed factor and needs to be chosen when you have either many VMs on one server or very data-intensive VMs.

It is true that Hyper-V is strong but it has a problem as well: it has to be installed on Windows Server 2008 or the lighter variant Hyper-V Server 2008. The latter is free of charge and you need to put it on a partition of its own.

VMware runs on all operating systems but isn't as good with backups.

In conclusion, VMware is flexible, Virtual PC is simple, Virtual Server is medium ground, and Hyper-V is Microsoft's alternative to VMware.