How Windows Vista Works

In some ways, Windows Aero is similar to recent versions of the Windows GUI, like the one used in Windows XP. Aero organizes information in on-screen windows and uses icons to represent files, folders and applications. But Aero also has several features that you can think of as upgrades to the Windows XP GUI. Its windows are three-dimensional objects that you can move and adjust in any direction. Aero Glass makes the borders of each window translucent so you can see the desktop or other windows behind it. Microsoft asserts that the clear border lets you focus on your work instead of on your interface [Source: Microsoft].

Vista also replaces the simple, static icons that represent many files in older Windows GUIs with more elaborate Live Icons. Live Icons give you up-to-date thumbnail previews of each file. When you look at a document's Live Icon, you see what the document actually looks like rather than seeing an icon for the program that created it. You can also look at the contents of files before opening them by using the Explorer preview pane.

Similar thumbnails also replace the icons you see when you use the "alt" and "tab" keys to move through open windows. Aero's more basic version of "alt + tab," called Flip, lets you choose from 2-D thumbnail previews on a menu bar. Another feature, Flip 3D, lets you choose from three-dimensional, moving thumbnails rather than 2-D images. In addition, if you hover your mouse over items on your taskbar, you'll see 2-D thumbnails of each window instead of text listing the applications and filenames.

Many elements of the Aero GUI, including the Start menu and the windows themselves, incorporate new search capabilities. While a computer is running, Vista scans the disc drive for changes and maintains a running index of its files. You can search this index from multiple locations within the GUI. For example, rather than moving your mouse through a series of cascading windows in the Start menu, you can simply type in the program or file you're looking for. You can also create search folders -- saved searches that you can return to when you need to find particular files or folders. Adding metadata, or tags, to your files can make these searches more efficient. When you search for a file, the computer examines filenames, tags and document contents to find relevant results.

In addition to the GUI, Vista comes with several new applications. Different versions include different features, but here's a sample of what's new:

Vista also has a few new tools intended to improve performance:

Because of its new features, particularly its 3-D GUI, Vista has different hardware requirements than previous versions of the OS. We'll look at these requirements and explore how Vista creates the 3-D desktop next.

Windows Vista's desktop environment requires considerably more computer resources than previous versions of the OS. For this reason, and to make the OS more stable, Vista's graphics subsystem is different from its predecessors.

First, Windows Vista uses a new graphics driver model, known as the Windows Display Driver Model (WDDM). Previous Windows graphics drivers ran in kernel mode. They had direct access to the graphics hardware, and their performance could affect the operating system. This is why graphics errors could cause the entire system to stop responding. WDDM, however, runs primarily in user mode. It has little direct access to the graphics hardware or to critical parts of the operating system. Microsoft instituted a similar change to Vista's audio subsystem as well. These changes should help make the OS more stable.

The WDDM manages the workload of the graphics processing unit (GPU). It allocates the video memory required for different tasks, and it prioritizes applications that need access to the GPU. In other words, it helps budget the computer's video processing resources. This is particularly important, since the OS and applications that use lots of 3-D graphics have to share the computer's graphics resources.

A driver called the Desktop Window Manager (DWM) is part of the WDDM. This driver is responsible for updating what you see on the desktop. The DWM draws all of the objects you see on your screen and holds them in a buffer until you need them. By keeping different desktop views in a buffer, the DWM should help prevent the blank square of space that often appears when programs stop responding. The DWM creates the thumbnails used in Flip and Flip-3D, and it can scale on-screen images to fill high-resolution monitors.

Although the WDDM is central to creating the windows you use to access your applications, it doesn't communicate with those programs directly. Instead, it interacts with programs through an application programming interface (API). APIs help hardware and software communicate more efficiently by providing sets of instructions for complex tasks. Windows Vista can use DirectX 9 as its API, although a new version, DirectX 10, is a built-in, exclusive part of the OS.

All this 3-D rendering requires lots of processing power. To use Aero and some of the more hardware-intensive features of Windows Vista, a computer must be Premium Ready. It has to have enough system and graphics memory to handle constant creation and manipulation of 3-D images. This is why the requirements for a Premium Ready computer sound like what you'd expect from a 3-D game. It must have:

The computer also has to support DirectX 9, have a DVD-ROM drive and have access to the Internet. Microsoft has a list of all of the necessary components for a Premium Ready system.

If you're considering upgrading to Windows Vista and want to use the Aero interface, you should keep in mind that these are the minimum requirements. If your computer meets exactly these specifications, it will be able to create the 3-D interface. However, it may bog down if you're multitasking or playing image-intensive games. If you hope to run Vista on a laptop or a desktop that doesn't have a dedicated video card, you may find that the GUI's benefits don't outweigh the strain it puts on your system resources. To get optimal performance from the Aero user interface, a computer needs to exceed the minimum recommendations, including a separate video card with its own graphics memory.

Microsoft has published different minimum requirements for computers using the basic interface. They include:

Microsoft has also made some changes to how Vista handles networking and security. We'll look at these changes in the next section.

In the past, computer networks primarily existed in schools, businesses and computer enthusiasts' homes. But today, many households have several computers that need to share files, printers and connections to the Internet. Unlike most businesses, many average home users do not have a networking expert to set up and maintain their networks.

For this reason, Windows Vista includes several network setup wizards, which walk users through creating networks and sharing devices. It also has several built-in network tools that are accessible through a Network Center:

Vista also includes a Network Awareness feature for people who need to use their computers in multiple locations. Network Awareness detects which network a person's computer is using and applies the appropriate settings.

Vista also includes tools to help people maintain and repair their own networks. The Network Diagnostics feature can detect and repair some network issues on its own. It can also walk users through the necessary steps to restore their network connections. To do this, it uses a collection of tools that use the Windows Diagnostic Infrastructure (WDI).

The WDI provides the structure for several components, including the Network Diagnostics Framework (NDF) and several APIs. The NDF identifies and troubleshoots client-side network issues using a Network Diagnostics Engine as well as Microsoft and third-party helper classes. The helper classes are troubleshooting protocols, and the Network Diagnostic Engine communicates with them through the helper class API. Applications that need to access the Internet can also use APIs to access Vista's troubleshooting capabilities.

Other changes to Vista should improve computers' security once they're connected to a network or the Internet. Some experts blame the Windows kernel for previous issues with security [Source: Extreme Tech]. Although Vista uses essentially the same kernel as previous versions of Windows, Microsoft has made some changes to how applications interact with it. In addition to making the computer more stable, this change will also make it more difficult for people to write malicious code designed to exploit applications and affect the kernel.

Vista also includes applications and tools that people can use to make their systems more secure. As with previous versions of Windows, Vista can check for, download and install security updates automatically. In addition, it has several new security features:

Although Microsoft has presented Vista as safer and more secure than previous versions of Windows, the new OS is not without controversy. Critics have pointed out that many of its features, including search, Sidebar and preview pane functions, already exist in other operating systems, like Linux and Macintosh OS X. Beta testers have described the UAC password requirements as invasive and annoying. Some claim that the improved security that comes from changes to how applications interact with the kernel will be short-lived. Vista has also been accused of antitrust violations in several countries, particularly because of its integrated malware removal tools.

Other criticism is laptop-specific. Aero's hardware requirements for 3-D rendering may drain laptop batteries more quickly than older versions of Windows. The sleep state may also drain laptop batteries when the laptops are not in use.

Vista hit the market for volume license buyers on November 30, 2006, and it became available to the public on January 30, 2007. With the 3-D GUI and related hardware requirements, it has the potential to change how people shop for computers, especially when it comes to graphics hardware. Only time will tell whether the differences between Windows Vista and prior versions make it a more stable, secure OS or whether its most significant changes are cosmetic.

Check out Microsoft's site for more detailed information about Windows Vista's features and costs. See the links on the next page for more information on computers, operating systems and related topics.