Features new to Windows XP

Windows XP introduced many features not found in previous versions of Windows.

GDI+ powered graphics architecture
With the introduction of Windows XP, GDI was deprecated in favor of its successor, the C++ based GDI+ subsystem. GDI+ adds anti-aliased 2D graphics, textures, floating point coordinates, gradient shading, more complex path management, intrinsic support for modern graphics-file formats like JPEG and PNG, and support for composition of affine transformations in the 2D view pipeline. GDI+ uses ARGB values to represent color. Use of these features is apparent in Windows XP's user interface (drop shadows for icon labels on the desktop, shadows under menus, translucent blue selection rectangle in Windows Explorer, sliding task panes and taskbar buttons), and several of its applications such as Microsoft Paint, Windows Picture and Fax Viewer, Photo Printing Wizard, My Pictures Slideshow screensaver, and their presence in the basic graphics layer greatly simplifies implementations of vector-graphics systems such as Flash or SVG. The GDI+ dynamic library can be shipped with an application and used under older versions of Windows.

Start menu and Taskbar
With Windows XP, the taskbar and the Start button have been updated to support Fitt's law. To help the user access a wider range of common destinations more easily from a single location, the Start menu was expanded to two columns; the left column focuses on the user's installed applications, while the right column provides access to the user's documents, and system links which were previously located on the desktop. Links to the My Documents, My Pictures and other special folders are brought to the fore. The My Computer and My Network Places (Network Neighborhood in Windows 95 and 98) icons were also moved off the Desktop and into the Start menu, making it easier to access these icons while a number of applications are open. Moreover, these links can be configured to expand as a cascading menu. Frequently used programs are automatically displayed in the left column, newly installed programs are highlighted, and the user may opt to "pin" programs to the start menu so that they are always accessible without having to navigate through the Programs folders. The default internet browser and default email program are pinned to the Start menu. The Start menu is fully customizable, links can be added or removed; the number of frequently used programs to display can be set. The All Programs menu expands like the classic Start menu to utilize the entire screen but can be set to scroll programs. The user account picture is also shown on the Start menu.

The taskbar now supports locking and unlocking to prevent itself from being accidentally resizes or elements such as Quick launch and other DeskBands from being moved inadvertently. The Taskbar grouping feature combines multiple buttons of the same application into a single button, which when clicked, pops up a menu listing all the grouped windows and their number. Advanced taskbar grouping options can be configured from the registry. The user can choose to always show, always hide or hide some or all notification area icons if inactive for some time. A button allows the user to reveal all the icons.

Windows Explorer
There are significant changes made to Windows Explorer in Windows XP, both visually and functionally. Microsoft focused especially on making Windows Explorer more discoverable and task-based, as well as adding a number of features to reflect the growing use of a computer as a “digital hub”.

Task pane and navigation pane
The task pane is displayed on the left side of the window instead of the traditional folder tree view when the navigation pane is turned off. It presents the user with a list of common actions and destinations that are relevant to the current directory or file(s) selected. For instance, when in a directory containing mostly pictures, a set of “Picture tasks” is shown, offering the options to display these pictures as a slide show, to print them, or to go online to order prints. Conversely, a folder containing music files would offer options to play those files in a media player, or to go online to purchase music.

Every folder also has “File and Folder Tasks”, offering options to create new folders, share a folder on the local network, publish files or folders to a web site, and other common tasks like copying, renaming, moving, and deleting files or folders. File types that have identified themselves as being printable also have an option listed to print the file.

Underneath “File and Folder Tasks” is “Other Places”, which always lists the parent folder of the folder being viewed and includes additional links to other common locations such as “My Computer”, “Control Panel”, and “My Documents” or previously navigated locations. These change depending on what folder the user was in.

Underneath “Other Places” is a “Details” pane which gives additional information when a file or folder is selected – typically the file type, file size and date modified, but depending on the file type, author, image dimensions, attributes, or other details. If the file type has a Thumbnail image handler installed, its preview also appears in the "Details" task pane. For music files, it might show the artist, album title, and the length of the song. The same information is also shown horizontally on the status bar.

The “Folders” button on the Windows Explorer toolbar toggles between the traditional navigation pane containing the tree view of folders, and the task pane. Users can also close the navigation pane by clicking the Close button in its right corner as well as turn off the task pane from Folder Options.

The navigation pane has been enhanced in Windows XP to support "simple folder view" which when turned on hides the dotted lines that connect folders and subfolders and makes folders browsable with single click while still keeping double clicking on in the right pane. Single clicking in simple folder view auto expands the folder and clicking another folder automatically expands that folder and collapses the previous one.

Search
Microsoft introduced animated “Search Companions” in an attempt to make searching more engaging and friendly; the default character is a puppy named Rover, with three other characters (Merlin the magician, Earl the surfer, and Courtney) also available. These search companions powered by Microsoft Agent technology, bear a great deal of similarity to Microsoft Office’s Office Assistants, even incorporating “tricks” and sound effects. However, search companion can be turned off and the user can revert to using classic search.

The search capability itself is fairly similar to Windows Me and Windows 2000, with some important additions: Search can also be instructed to search only files that are categorically “Documents” or “Pictures, music and video"; this feature is noteworthy largely because of how Windows determines what types of files can be classified under these categories . Another important addition is that the "Look in" field accepts environment variables. Also, users can configure whether or not Windows XP searches for system and/or hidden files and folders.

Image handling
Windows XP improves image preview by offering a Filmstrip view which shows images in a single horizontal row and a large preview of the currently selected image above it. “Back” and “Previous” buttons facilitate navigation through the pictures, and a pair of “Rotate” buttons offer 90-degree clockwise and counter-clockwise rotation of images. Filmstrip view like any other view can be turned on per folder. Aside from the Filmstrip view mode, there is a 'Thumbnails' view, which displays thumbnail-sized images in the folder and also displays images a subfolder may be containing (4 by default) overlaid on a large folder icon. A folder's thumbnail view can be customized from the Customize tab accessible from its Properties, where users can also change the folder's icon and specify a template type (pictures, music, videos, documents) for that folder and optionally all its subfolders. The size and quality of thumbnails in "Thumbnails" view can be adjusted using Tweak UI or the registry. Exif metadata stored in the image is also shown in the file's Properties -> Summary tab, in "Details" view and in any view on the status bar. Windows XP optionally caches the thumbnails in a "Thumbs.db" file in the same folder as the pictures so that thumbnails are generated faster the next time.

Other shell improvements

 * AutoPlay and extensible AutoPlay handlers
 * Customizable infotips on a per-file-class (file type) basis without writing shell extensions
 * In Windows XP, a "WebDAV mini-redirector" has been added which is preferred over the old Web folders client, by default. This newer client works as a system service at the network-redirector level (immediately above the file-system), allowing WebDAV shares to be assigned to a drive letter and used by any software. The redirector also allows WebDAV shares to be addressed via UNC paths (e.g.  http://host/path/  is converted to \\host\path\) for compatibility with Windows filesystem APIs. The WebDAV mini-redirector is known to have some limitations in authentication support.
 * Windows Explorer is content-dependent, that is, it attempts to detect the dominant type of files in a folder and then selects the most appropriate view for the user automatically unless the user manually sets the view.
 * Windows XP introduced a large number of metadata categories which are shown as columns in the "Details" view of Explorer. Users also gain the ability to sort by any category which is turned on in "Details" view. Developers can write column handler shell extensions to further define their own metadata categories by which files can be sorted.
 * The right pane of Windows Explorer has a "Show in Groups" feature which allows Explorer to separate its contents by headings based on any field which is used to sort the items. Items can thus be grouped by any detail which is turned on. "Show in Group" is available in Thumbnails, Tiles, Icons and Details views.
 * A "Tiles" view was added, which displays the file’s icon in a larger size (48 &times; 48), and places the file name, descriptive type, and additional information by which the items are sorted (typically the file size for data files, and the publisher name for applications) to the right.
 * The toolbars can be locked to prevent them from being accidentally moved. This same capability was also added to Internet Explorer’s toolbars.
 * The sort order has changed compared to the one in Windows 2000. For file names containing numbers Windows Explorer now tries to sort based on numerical value rather than just comparing each number digit by digit for every character position in the file name. For instance, files containing "1", "2".."10" will be intuitively sorted with "10" appearing after "9" instead of appearing between "1" and "2".
 * The "Line up icons" feature in the context menu has been replaced by an "Align to grid" feature which when turned on always lines up icons.
 * For unknown/undefined file types which inexperienced users may get confused when double clicked, Windows XP can contact a web service which shows additional information about that file type and what program created or can open that file type.
 * If an image named "Folder.jpg" is placed inside a folder, that image will be used as the thumbnail for that folder and as Album Art for media files in Windows Media Player.
 * EFS-encrypted files can be shown in an alternate color beginning with Windows XP.
 * File and folder size information is shown in tooltips upon mouse hover. For folders, size and partial folder contents are shown.
 * When opening more than 15 files in a single operation, i.e. by selecting multiple files and pressing enter, Windows XP warns the user that Windows Explorer may become unresponsive, but still allows the user to do so.
 * Windows Explorer supports a very basic form of mass renaming items.
 * A hyperlink control in system supplied common controls.

Other usability improvements

 * Windows XP includes a new set of visual themes or styles, known by its codename, Luna. Available in three color schemes, the interface is more task-based than the basic one included since Windows 95, with options available in Explorer windows to interact with each file. The user can however choose to fully revert to the pre-Windows XP "classic" user interface.
 * Windows XP's Display Properties allows users to save their customizations as Themes. This feature was previously available for earlier Windows operating systems by installing Microsoft Plus!.
 * Windows XP includes ClearType sub-pixel font anti-aliasing, which makes onscreen fonts smoother and more readable on liquid crystal display (LCD) screens, although this causes a minor performance degradation. Although ClearType has an effect on CRT monitors, its primary use is for LCD/TFT-based (laptop, notebook and modern 'flatscreen') displays.
 * Icon support for 24-bit color depth with an 8-bit alpha channel.
 * Use of black dots instead of asterisks in password fields of a TextBox control e.g. ●●● instead of ***

Performance improvements
The Windows XP kernel is completely different from the kernel of the Windows 9x/Me line of operating systems. Although an upgrade of the Windows 2000 kernel, there are major scalability, stability and performance improvements, albeit transparent to the end user.

Memory management improvements
The paged pool limit of 470 MB has been lifted from the Memory Manager in Windows XP, and data structures are allocated only for parts of a file that have active views, with unmapped views reusable by the memory manager depending on pool usage. Windows XP supports a larger system virtual address space (1.3 GB, of which the contiguous virtual address space that can be used by device drivers is 960 MB). The registry is reimplemented outside of the paged pool; the registry hives are memory mapped by the Cache Manager into the system cache, eliminating the registry size limit. The Configuration Manager has been updated to minimize the registry's memory footprint and lock contention, reduce fragmentation and speed up query processing.

The kernel page write protection limit in Windows XP is enabled on systems up to 256 MB of RAM (instead of 128 MB for earlier versions) beyond which large pages are enabled. Memory pages in working sets are trimmed more efficiently for multiprocessor systems depending on how recently they were accessed. Lock contention is reduced, as a number of unnecessary locks used in resource synchronizations (RAM allocation and mapping through Address Windowing Extensions, system page table entries, charging nonpaged/paged pool quotas, charging commitment of pages) have been removed. The dispatcher lock contention has been reduced and the Page Frame Number (PFN) lock has been optimized for increased parallelism and granularity. Windows XP uses push locks if there is no contention as they support shared and exclusive acquisition. Push locks are used to protect handle table entries, and in the Object Manager (to protect data structures and security descriptors) and Memory Manager (to protect AWE-related locks). Windows XP uses the SYSENTER/SYSEXIT mechanisms which require fewer clock cycles to transition to and from user mode to kernel mode to speed up system calls.

Windows XP includes simultaneous multithreading support. Simultaneous multithreading is a processor's ability to process more than one data thread at a time.

Faster boot and logon
The ability to boot in 30 seconds was a design goal for Windows XP, and Microsoft's developers made efforts to streamline the system as much as possible; The Prefetcher is a significant part of this; it monitors what files are loaded during boot, optimizes the locations of these files on disk so that less time is spent waiting for the hard drive's heads to move and issues large I/O requests that can be overlapped with device detection and initialization. The prefetcher also uses the same algorithms to reduce application startup times. Activities such as system and service cleanup, and layout optimization of files and file metadata take place at idle time.

The Fast Logon Optimization feature performs logon asynchronously without waiting for the network to be fully initialized if roaming user profiles are not set up. Use of cached credentials avoids delays when logging on to a domain. Group Policy is applied in the background, and startup or logon scripts execute asynchronously by default.

Side-by-side (SxS) assemblies
A common issue in previous versions of Windows was that users frequently suffered from DLL hell, where more than one version of the same dynamically linked library (DLL) was installed on the computer. As software relies on DLLs, using the wrong version could result in non-functional applications, or worse. Windows XP solved this problem for native code by introducing side-by-side assemblies. The technology keeps multiple versions of a DLL in the WinSxS folder and runs them on demand to the appropriate application keeping applications isolated from each other and not using common dependencies.

Application isolation
Windows XP also introduced a new mode of COM object registration called Registration-free COM. This makes it possible for applications that need to install COM objects to store all the required COM registry information in the application's directory, instead of in the global registry, where, strictly speaking, only a single application will ever use it. DLL hell can be substantially avoided using Registration-free COM, the only limitation being it requires at least Windows XP or later Windows versions and that it must not be used for EXE COM servers or system-wide components such as MDAC, MSXML, DirectX or Internet Explorer.

Application compatibility
As Windows XP merged the consumer and enterprise versions of Windows, it was necessary to support applications developed for the popular and consumer oriented Windows 9x platform on the Windows NT kernel. Microsoft addressed this by going to great lengths to improve compatibility with application specific tweaks and shims and providing tools such as the Application Compatibility Toolkit to allow users to apply and automate these tweaks and shims on their own applications.

Device support improvements
Windows XP provides new and/or improved drivers and user interfaces for devices compared to Windows Me and 98.

CD burning
Windows XP includes technology from Roxio which allows users to directly burn files to a compact disc through Windows Explorer. Previously, end users had to install CD burning software. In Windows XP, CD and DVD-RAM (FAT32 only for DVD-RAM) burning has been directly integrated into the Windows interface; users burn files to a CD in the same way they write files to a floppy disk or to the hard drive. The burning functionality is also exposed as an API called the Image Mastering API. Windows XP's CD burning support does not do disk-to-disk copying or disk images, although the API can be used programmatically to do these tasks. Creation of audio CDs is integrated into Windows Media Player.

Device Driver Rollback
On old versions of Windows, when users upgrade a device driver, there is a chance the new driver is less stable, efficient or functional than the original. Reinstalling the old driver can be a major hassle and to avoid this quandary, Windows XP keeps a copy of an old driver when a new version is installed. If the new driver has problems, the user can return to the previous version. This feature does not work with printer drivers.

Power management improvements

 * Support for the Simple Boot Specification
 * Wake-on-Battery support so that the system has time to power off or hibernate
 * LCD dimming when on battery power
 * Processor power and performance control including C-state (run in lower power state when idle) and throttling
 * USB selective suspend feature
 * Significantly noticeable fast boot and resume from hibernation compared to previous Windows versions owing to the boot loader caching file and directory metadata sequentially and in large chunks in a most recently used manner, overlapping device initialization. Hibernation is faster as memory pages are compressed using an improved algorithm, unused memory pages are freed and DMA transfers are used during I/O.
 * Faster resume from standby as the algorithm used by the Power Manager for notifying hardware and software of power state changes by dispatching power IRPs has been rewritten to maximize parallelism and important system drivers (PCMCIA, keyboard, mouse) have been rewritten to eliminate blocking interactions.
 * Built-in support for processor power management technologies such as Intel SpeedStep and AMD PowerNow!.

Other hardware improvements

 * Windows XP's user interface for Plug and Play changed with all messages being shown in the notification area as balloon tips.
 * Generic USB 2.0 EHCI drivers beginning with Windows XP SP1 and support for USB device classes such as Bluetooth, USB video device class, imaging (still image capture device class) and Media Transfer Protocol with Windows Media Player 10 USB audio devices support GFX filters
 * FireWire (IEEE 1394) support for digital video cameras and audio video devices, MPEG-2 and S/PDIF across IEEE 1394 (IEC-61883 and AV/C protocols).
 * The read-only attribute of files and folders is automatically removed when copying files from optical media using Windows Explorer.
 * Improved mouse pointer ballistics.
 * DualView for multi-monitor setups.
 * The Scanner and Camera Wizard based on Windows Image Acquisition and other common dialogs for WIA devices have been improved in Windows XP to show the media information and metadata, rotate images as necessary, categorize them into subfolders, capture images and video in case of a still or video camera, crop and scan images to a single or multi-page TIFF in case of a scanner.
 * Multichannel audio output and playback of additional audio formats. Volume can be set for each speaker in a multichannel configuration.
 * Acoustic Echo Cancellation for USB microphones
 * Global Effects (GFX) engine
 * Support for reading UDF 2.01 upgradeable to UDF 2.50 by installing Windows Feature Pack for Storage.
 * Sound Blaster 2.0 emulation support in NTVDM

Remote Desktop
Users can log into Windows XP Professional remotely through the Remote Desktop service. It is built on Terminal Services technology (RDP), and is similar to "Remote Assistance", but allows remote users to access local resources such as printers. . Any Terminal Services client, a special "Remote Desktop Connection" client, or a web-based client using an ActiveX control may be used to connect to the Remote Desktop. (Remote Desktop clients for earlier versions of Windows, Windows 95, Windows 98 and 98 Second Edition, Windows Me, Windows NT 4.0, or Windows 2000 have been made available by Microsoft . This permits earlier versions of Windows to connect to a Windows XP system running Remote Desktop, but not vice-versa.)

There are several resources that users can redirect from the remote server machine to the local client, depending upon the capabilities of the client software used. For instance, "File System Redirection" allows users to use their local files on a remote desktop within the terminal session, while "Printer Redirection" allows users to use their local printer within the terminal session as they would with a locally or network shared printer. "Port Redirection" allows applications running within the terminal session to access local serial and parallel ports directly, and "Audio" allows users to run an audio program on the remote desktop and have the sound redirected to their local computer. The clipboard can also be shared between the remote computer and the local computer.

Remote Assistance

 * Remote Assistance allows a Windows XP user to temporarily take over a remote Windows XP computer over a network or the Internet to resolve issues. As it can be a hassle for system administrators to personally visit the affected computer, Remote Assistance allows them to diagnose and possibly even repair problems with a computer without ever personally visiting it.

Fast user switching and Welcome Screen
Windows XP introduces Fast User Switching and a more end user friendly Welcome Screen which replaces the Classic logon prompt. Fast user switching allows another user to log in and use the system without having to log out the previous user and quit his or her applications. Previously (on both Windows Me and Windows 2000) only one user at a time could be logged in (except through Terminal Services), which was a serious drawback to multi-user activity. Fast User Switching, like Terminal Services, requires more system resources than having only a single user logged in at a time and although more than one user can be logged in, only one user can be actively using their account at a time. This feature is not available when the Welcome Screen is turned off, such as when joined to a Windows Server Domain or with Novell Client installed.

Other manageability features

 * Windows Disk Defragmenter was updated to alleviate some restrictions. It no longer relies on the Windows NT Cache Manager, which prevented the defragmenter from moving pieces of a file that cross a 256KB boundary within the file.  NTFS metadata files can also be defragmented.  A command-line tool, defrag.exe, has been included, providing access to the defragmenter from cmd.exe and Task Scheduler.
 * Non-persistent Shadow Copy support
 * NTBackup has a wizard-based interface for ease of use and supports backing up locked files using Shadow Copy.
 * Windows Error Reporting
 * Driver Verifier Manager, a GUI for Driver Verifier.
 * Automated System Recovery
 * Unified Registry editor
 * Files and Settings Transfer Wizard and User State Migration Tool
 * Several deployment tools improvements including enhancements to Sysprep, Setup Manager, introduction of WinPE
 * Increased number of Group Policies and Resultant Set of Policy (RSoP) management console which allows administrators to see applied policies in logging mode or simulate policy settings that will be applied before committing to changes to objects in planning mode.
 * A Desktop Cleanup Wizard was introduced to help users reduce clutter on their desktops, by looking at the shortcuts on the Desktop and moving any unused ones into a directory called "Unused Desktop Shortcuts". The Desktop Cleanup Wizard operates as a scheduled task that runs once a day to determine if it's been 60 days since the last time the wizard was run.

Networking and communication features

 * IPv6 and Teredo tunneling through the Advanced Networking Pack later incorporated into Windows XP SP2, the combination of which helps traverse symmetric NATs.
 * DHCP client alternate configuration to support more than one network or in the case when a DHCP server is not available
 * Network bridging
 * Internet Connection Firewall later upgraded to Windows Firewall in Windows XP Service Pack 2.
 * Network Setup Wizard for setting up the network, an evolution of Windows Me's Home Networking Wizard.
 * NAT Traversal APIs to abstract UPnP functions. UPnP IGD devices show up in Network Connections if the IGD Discovery and Control client is installed and double clicking their icon can initiate a connection to the Internet via the gateway device and show status information. NAT port mappings are also shown and can be set up.
 * Internet Connection Sharing is integrated with UPnP and has a Quality of Service Packet Scheduler component
 * Built-in PPPoE protocol
 * Connection Manager supports favorites to save settings for multiple network locations, client side logging and callback features
 * Peer-to-peer networking support later expanded with Advanced Networking Pack/Windows XP SP2 which introduced Peer Name Resolution Protocol that allows dynamic domain name publication and resolution of names to endpoints.
 * Support for IP networking over the IEEE 1394 bus.
 * Background Intelligent Transfer Service
 * Wireless Zero Configuration for automatic wireless network configuration with re-authentication when necessary thus providing seamless roaming capability and setting the preferred order of connections
 * IEEE 802.1X support for wireless and wired connections
 * Ability to access hotspots created using Wireless Provisioning Services
 * Ability to establish an ad hoc wireless network
 * Native support for WPA and WPA2 in infrastructure networks
 * Improved support for infrared including IrDA networking (IrCOMM modems, IrNET and P2P)
 * Network connection status support tab which displays IP configuration and offers a 1-click "Repair" function to perform a series of steps that reset the network connection.
 * Networking tab in Windows Task Manager
 * Basic Network Diagnostics integrated into the Help and Support Center \
 * Winsock has the ability to self-heal if a Winsock LSP uninstallation damages it. Also, users can manually reset and repair a corrupted Winsock stack using the netsh winsock reset command.
 * Network Location Awareness APIs exposed through Winsock for determining network states and notifying Winsock client applications of changes
 * Support for split tunneling (although not secure) for VPN connections so VPN clients may access the internet
 * Support for PVC Encapsulation (RFC 2684)
 * NDIS 5.1 has performance enhancements, Plug and Play and Power event notifications for miniport drivers, send cancellation and 64-bit statistic counters. Remote NDIS supports USB attached network devices.
 * Wake on LAN can be configured to limit wake up packets to just magic packets.
 * Expanded support for soft modems and HomePNA adapters.
 * TAPI 3.1 exposes COM interfaces. H.323v2 based IP telephony and IP multicast AV conferencing Telephony Service Providers are included. TAPI 3.1 also includes File Terminals, Pluggable Terminals, USB Phone TSP and support for Auto Discovery of TAPI Servers. Several H.323 supplementary services have been implemented for richer call control features.
 * Support for simple file sharing which disables the Security tab used to set ACLs/permissions and enables sharing of files and folders over the network without asking for a password. Simple file sharing also disables sharing permissions (shares the item with everyone on the network) but users can make folders in their user profile inaccessible.
 * Native Bluetooth stack beginning with Windows XP Service Pack 2.
 * Windows Messenger

Security features

 * Software Restriction Policies
 * Credential Manager API with a Single Sign On mechanism
 * Network logons disabled for user accounts with blank passwords.
 * Several Encrypting File System improvements
 * Digest SSP for HTTP and LDAP queries
 * Smart Card login to terminal server sessions, using smart cards with system tools such as net.exe and runas.exe, auto-enrollment for smart cards
 * Data Execution Prevention, Windows Security Center, Attachment Manager introduced in Windows XP SP2

Other features

 * Windows XP supports a total of 1 million card deals in its version of FreeCell.
 * For computers in a workgroup, the Windows Time Service in Windows XP supports a new Internet Time feature (NTP client), which updates the clock on the user's computer by synchronizing with an NTP time server on the Internet. This feature is useful for computers whose real-time clock does not maintain the correct time.
 * Video Mixing Renderer-7 (VMR-7) DirectShow renderer filter for video rendering. VMR-7 which can mix multiple streams and graphics with alpha blending, allowing applications to draw text and graphics over the video and support custom effects.
 * Internet Information Services 5.1
 * Microsoft Message Queuing 3.0 supports: Internet Messaging (referencing queues via HTTP, SOAP-formatted messages, MSMQ support for Internet Information Services), queue aliases, multicasting of messages, and additional support for programmatic maintenance and administration of queues and MSMQ itself. MSMQ 3 clients directly communicate with Active Directory using LDAP.
 * COM+ 1.5
 * Speech Application Programming Interface 5.1
 * SAPI 5 support in Microsoft Narrator
 * General improvements to international support such as more locales, languages and scripts, MUI support in Terminal Services, improved IMEs and National Language Support, Text Services Framework beginning with Windows XP SP1.
 * Full Unicode support in the RichEdit control shipped in Windows XP and used by WordPad.
 * Support for tablet and pen-sensitive screens, portrait-oriented screens in Windows XP Tablet PC Edition. It also includes speech recognition to control the operating system and for text dictation, handwriting recognition and digital ink support accessible through the Tablet PC Input Panel (TIP). Also included are applications to complement these features such as Windows Journal and Sticky Notes for note taking with additional downloadable applications and extras.
 * Microsoft Active Accessibility 2.0 API, adding support for Dynamic Annotation and MSAA Text.