If you're using OS X Lion or later, you can setup a second copy of OS X to be used as a guest operating system alongside your main system, without having to purchase or download another copy of OS X.
An Internet connection to download and install freely available operating system such as Ubuntu or Google Chrome. #PARALLELS DESKTOP 9 FOR MAC MAC EMULATOR MAC OS X#
A Windows installation disc, or other installation media for the operating systems you want to use alongside Mac OS X. Internet connection required for product activation, select features, and online updates. To identify your computer's processor, memory, and Mac OS X version, choose Apple menu > About This Mac. OS X 10.10 Yosemite or later, OS X 10.9.3 Mavericks or later, OS X 10.8.5 Mountain Lion or later, or OS X 10.7.6 Lion or later. Enough free disk space for each virtual machine and its applications (at least 15 GB for each installation of Windows). At least 850 MB of space available on the boot volume (the volume that has Mac OS X) for Parallels Desktop installation. An Intel Core 2 Duo processor or better. System Requirements Minimum System Requirements (Mac)