Many users install GSX Server on a dual-boot or multiple-boot computer so they can run one or more of the existing operating systems in a virtual machine. If you are doing this, you may want to use the existing installation of an operating system rather than reinstall it in a virtual machine.

To support such installations, GSX Server makes it possible for you to use a physical IDE disk or partition, also known as a raw disk, inside a virtual machine.

Setting up a physical disk configuration for a virtual machine is more complicated than using a virtual disk. Virtual disks are recommended unless you have a specific need to run directly from a physical disk or partition.

You may sometimes want to run an operating system inside a virtual machine and at other times want to run that same installation of the operating system by booting the host computer directly into that operating system. If you want to use this approach, you must be aware of some special considerations

The issues arise because the virtual hardware that the operating system sees when it is running in a virtual machine is different from the physical hardware it sees when it is running directly on the host computer. It is as if you were removing the boot drive from one physical computer and running the operating system installed there in a second computer with a different motherboard, video card and other peripherals — then moving it back and forth between the two systems.

The general approach for resolving these issues is to set up profiles for each of the two operating environments — the virtual machine and the physical computer. You can then choose the appropriate profile when you start the operating system. On some hardware, however, booting a previously installed operating system within a virtual machine may not work.

Technical notes in this section document the issues most commonly encountered with various guest operating systems. Read the notes that apply to your guest operating system before you begin to set up your virtual machine.

Before you begin, be sure to read all the sections listed under the name of the operating system you intend to run as a guest in a virtual machine.

It is also possible to install a guest operating system on a physical disk when you plan to use that disk only within a virtual machine. For details on setting up a such a configuration, see Installing an Operating System onto a Physical Partition from a Virtual Machine.