Have you ever wondered how a piece of software like PCMark05 works? There are two parts of the program, which are executed at the same time. The first part is an interface that let you view the results from each type of test you perform, and the second part is a checker that run on your system to make sure the results from the tests you've performed were accurate. The interface is simple and easy to use, and just about anyone can figure out how to use it. It's so much easier than using the Windows interface, because you don't have to spend time learning how to navigate and use the mouse.
When you download the software, it will run through a series of tests and create a report, which will tell you how well the software ran for the type of test it was designed for. There are several different types of tests that you can perform, and they all have different requirements on how the software works. To make sure that you get a fair comparison, the test must compare the two operating systems and must be compatible with them. If it isn't, then it doesn't really matter if the software actually runs on the computer.
The checker is the software that runs in the background of Windows to ensure that the test reports you've just run are accurate. The reason the interface displays the results of the test is to help you see whether or not you're getting accurate results from the software. After the software runs the test, it compares the results from it to the results from the software, and then prints out a report of what it found. This is how the software provides you with an accurate report of the test results that it ran.