Sometimes a different OS (other than the one you are running on your machine) is needed for testing purpose. Vmware technology provides a convenient way (not so convenient, but it's easier than getting another machine and install, or install another OS on local machine) to do this.
For example, by using vmware, there are 2 steps to use a Linux system like Suse, on Windows OS:
(1) Making an image of the target Linux system (guest OS).
(2) Use vmware player (which is available in vmware.com) to run the image.
But how to make the image of the guest OS? Here are several steps:
(1) You must ensure that you have enough space required by the guest OS. You should get VMWare Disk Image (a VMDK file) and a VMX file in order to describe the virtual machine.
(2) These files are downloadable in Forever For Now Blog .
(3) Put these 2 files in a directory and edit the vmx file to set up the guest OS description and installation image.
(4) Use vmplayer to run the image.
(5) The installation of the guest OS will automatically starts......
The detailed installation guide can be found at vmplayer documentation site.