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How Windows Vista Works
by Tracy V. Wilson
Browse the article How Windows Vista Works
Introduction to How Windows Vista Works
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
Photo courtesy © 2006 Microsoft Corporation. All rights
numerous full-fledged versions of the
reserved.
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-thescenes jobs:
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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.
Thank You
Thanks to Jason Caudill for his
assistance with this article.
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 graphicsintensive 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.
Additional Editions
In addition to the four primary editions of Windows Vista, there are
two editions for special markets. Windows Vista Enterprise is
designed for very large businesses. Windows Vista Starter is a
basic Vista OS for use in emerging markets, such as developing
countries.
Windows Vista: Aero
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].
Photo courtesy © 2006 Microsoft Corporation. All rights reserved.
Aero Glass
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.
Photo courtesy © 2006 Microsoft Corporation. All rights reserved.
Flip 3D
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.
Photo courtesy © 2006 Microsoft Corporation. All rights reserved.
The Start search menu
In addition to the GUI, Vista comes with several new
WinFS
applications. Different versions include different features, While developing Windows
but here's a sample of what's new:
Vista, Microsoft planned to

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incorporate a new file system
called WinFS. Short for
Windows Future System, WinFS
stored data in a relational
database. Rather than storing
information in a series of folders
and subfolders, WinFS would
create indexes of a drive's data.
In August 2004, Microsoft
announced that WinFS would
not be part of Vista. The
company instead added new
search capabilities to its existing
file structure.
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.
Sidebar
Vista also has a few new tools intended to improve performance:

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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'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 3D graphics have to share the computer's graphics resources.
Photo courtesy © 2006 Microsoft Corporation. All rights reserved.
Windows Vista desktop view
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 highresolution 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.
Cap Bits
Previous versions of DirectX
used capability bits, or cap
bits, to describe different
DirectX features. Hardware did
not necessarily have to support
all of the cap bits to be DirectX
compliant. For this reason,
video cards and other
components didn't always work
properly even if they were
DirectX compliant. DirectX 10
does away with this system,
designating only three features
as optional.
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:
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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:
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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.
Changing the Volume
You may have had the experience of trying to talk to someone
over IM while listening to music on your computer. Sometimes,
your choices are to hear your IM notification sounds blaring over
your music or to turn them off entirely. Windows Vista eliminates
this issue by allowing people to change the outbound volume of
each application.
Windows Vista: Networking and Security
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.
Photo courtesy © 2006 Microsoft Corporation. All rights reserved.
The Network Center
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:
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User Account Control (UAC) lets each
What's a Kernel?
Windows Vista user for a particular
A kernel is a small but integral
computer set up his own account. A user
piece of an operating system.
It's usually the first piece to load
with administrative privileges can
into the computer's memory,
determine what kind of applications
and it stays there while the
different accounts can install and what kind
computer runs. Many other
of changes they can make to the computer's
applications and devices rely on
setup. In many cases, installing software
the kernel extensively, so
problems with it can cause
and making changes to the operating
system-wide issues.
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.
Photo courtesy © 2006 Microsoft Corporation. All rights reserved.
The Family Safety Center
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.