Managing System Resources
THE part of Windows Vista that you see—the Vista desktop—is just part of the operating system. Behind this interface (under the hood, if you will) is the guts of the beast. Vista is more than just a pretty interface; it’s a robust engine that makes all the components of your computer system run.
The Windows Vista engine works by managing the data flow to all the different pieces of hardware (including key subsystems) of your PC. Vista manages the instructions that are fed to the central processing unit; the applications and drivers that are stored in system memory; the external and internal devices that are connected to your computer; and the disk drives that your computer uses to store your data. Think of Windows as a virtual traffic cop, managing the flow of data and instructions; it’s all quite complex, yet Windows handles any given operation in the blink of an eye.
Consider, for example, the simple act of clicking your mouse to open a dialog box. When you press your finger down on that mouse button, it sends an electric signal from the mouse to your computer. That signal is translated into a specific instruction in binary code, thanks to a small software program called a device driver, which is part of the Windows operating system. Windows takes the instruction from the device driver, interprets what it means, and then forwards the instruction to your computer’s CPU. The CPU processes the instruction, and then feeds the result back to Windows. Windows then accesses the currently running program, which is temporarily stored in system memory, and tells it to open the dialog box. The program does as it’s told, and feeds back to Windows the necessary information about what dialog box to open, and where. Windows takes that instruction, processes it as necessary, and then feeds the graphic information about the dialog box to a different device driver—this one for your PC’s video card. The video device driver translates Windows’ instruction into the appropriate electronic signal, and the dialog box appears on your computer monitor screen. This whole process occurs in the blink of an eye.
Although this sounds rather complicated, it’s actually an example of a very simple—and very common—operation. Windows manages dozens, if not hundreds, of these operations every hour, all in the background, all without you knowing what’s going on behind the scenes. The operating system just does its thing, routing the proper instructions to the proper devices and systems, making sure that no one operation gets in the way of any other one. There’s a lot of interrupting and pausing and restarting, but that’s the nature of the game—and it all happens behind the scenes, without troubling you, the user.
It’s all in a days work, as far as Windows Vista is concerned.