How Windows Vista Works

Photo courtesy © 2006 Microsoft Corporation. All rights reserved.

The first version of Microsoft Windows hit the market in 1983. But unlike today's versions of Windows, Windows 1.0 was not an operating system (OS). It was a graphical user interface that worked with an existing OS called MS-DOS. Version 1.0 didn't look much like newer versions, either -- not even Windows 3.0, which many people think of as the first real version of Windows. Its graphics were simpler and used fewer colors than today's user interfaces, and its windows could not overlap.

Windows has changed considerably since then. In the last 20 years, Microsoft has released numerous full-fledged versions of the operating system. Sometimes, newer versions are significantly different from older ones, such as the change from Windows 3.1 to Windows 95. Other new releases have seemed more like enhancements or refinements of the older ones, such as the multiple consumer versions of the OS released from 1995 to 2001.


Microsoft's newest version of its operating system is Windows Vista. For many users, upgrading to Vista won't seem as dramatic as the upgrade from 3.1 to Windows 95. But Windows Vista has a number of new features, both in the parts that you can see and the parts that you can't.

At its core, Windows Vista is still an operating system. It has two primary behind-the-scenes jobs:

  • Managing hardware and software resources, including the processor, memory, storage and additional devices
  • Allowing programs to work with the computer's hardware

If all goes well, this work is usually invisible to the user, but it's essential to the computer's operation. You can learn about these tasks in more detail in How Operating Systems Work.

But when many people think of operating systems, they think of the portion they can see -- the graphical user interface (GUI). The GUI is what people use to interact with the hardware and software on the computer. In Windows systems, features like the Start menu, the recycle bin and the visual representations of files and folders are all part of the GUI.

Windows Vista's GUI is a 3-D interface called Windows Aero. Of the four editions of Windows Vista, three -- Home Premium, Business and Ultimate -- support Windows Aero. Home Basic, the most scaled-down edition of the OS, uses a less graphics-intensive GUI instead of Aero. The other editions can also use this basic GUI, so people with older computers that can't support lots of 3-D graphics can still upgrade to Vista.

We'll take a closer look at the Aero GUI and other Vista features next.

Microsoft's Web site has more information on which features each edition includes.


Windows Vista: Aero

Aero Glass
Photo courtesy © 2006 Microsoft Corporation. All rights reserved.

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.

Flip 3D
Photo courtesy © 2006 Microsoft Corporation. All rights reserved.

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.

The Start search menu
Photo courtesy © 2006 Microsoft Corporation. All rights reserved.

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:

  • Sidebar allows you to access mini-applications called Gadgets. Sidebar is similar to Konfabulator or Macintosh OS X's Dashboard, which call their mini-applications Widgets.
  • Meeting Space is a teleconferencing program for small groups of Vista users.
  • Speech Recognition lets users control their computers and create documents using their voices. Vista has a speech-activated user interface as well as a general voice dictation application.
  • Windows Mail replaces Outlook Express for home users and includes anti-phishing tools.
  • Windows Calendar, also for home users, is an interactive calendar application. In addition to allowing users to keep track of appointments, it can be used to send e-mail invitations to events.
Photo courtesy © 2006 Microsoft Corporation. All rights reserved.

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

  • SuperFetch pre-loads frequently-used applications into the memory so they can start up faster.
  • ReadyBoost lets people add RAM to their system with a USB thumb drive.
  • Sleep lets you quickly resume working by storing files that are currently in use. On desktop computers, these files are saved in the computer's RAM and on the hard drive. On laptop computers, the files are saved to the hard drive only when the battery power wanes.

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: Creating a 3-D Desktop

Windows Vista desktop view
Photo courtesy © 2006 Microsoft Corporation. All rights reserved.

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:

  • A 1 GHz 32-bit or 64-bit processor
  • 1 GB of system memory
  • A 40 GB hard drive with at least 15 GB of free space
  • At least 128 MB of graphics memory

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:

  • An 800 MHz or better modern processor
  • 512 MB of system memory
  • A graphics processor that supports DirectX 9

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


Windows Vista: Networking and Security

The Network Center
Photo courtesy © 2006 Microsoft Corporation. All rights reserved.

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:


  • Network Explorer lets users find files on networked computers and move them from to place. It's similar to other Windows Explorers that let people find files on their own computers.
  • Network Map creates a visual map of all the computers and devices on the network.

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:

  • User Account Control (UAC) lets each Windows Vista user for a particular computer set up his own account. A user with administrative privileges can determine what kind of applications different accounts can install and what kind of changes they can make to the computer's setup. In many cases, installing software and making changes to the operating system requires an administrator's password.
  • UAC also lets parents use parental controls to manage what kind of games their children can play and what kind of Web content they can view. Parents can also set time limits for computer use.
  • User Account Control, Windows Firewall, Windows Defender and the Malicious Software Removal Tool improve system security and help prevent and remove viruses and Spyware. However, many industry experts advise users to install additional virus protection.
The Family Safety Center
Photo courtesy © 2006 Microsoft Corporation. All rights reserved.

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.


Frequently Answered Questions

Is Windows 7 and Vista the same?
Windows 7 and Windows Vista are not the same. Windows 7 was released after Windows Vista and has different features.

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