Windows XP is a 32-bit operating system but a 64-bit version is also available. Microsoft created Windows XP in two different versions: Home and Professional. Windows XP Home is for personal computers and Windows XP Professional is for a business environment. The following list shows you the features available in both versions.

• Supports disk quotas to limit users on storage space.
• Core reliability and stability like Windows 2000.
• Enhanced support for movies. pictures. and music.
• Contains Windows Messenger that is a collaboration tool for instant messaging and video conferencing.
• Supports Internet Connection Firewall (ICS). which can help prevent attacks to your computer from hackers when connected to the Internet.
• Improved boot and power resume performance.
• Can automatically configure 802.lx wireless networks
• Allows you to view output on multiple monitors. This is called DualView.
• CDs can be made using drag-and-drop or the CD Writing Wizard.
• Supports WIA (Windows Image Acquisition). which allows communication between software application and image-capturing devices. The Scanner and Camera wizard is used to retrieve images from any WIA-enabled device.
• Can switch between users without rebooting.

There are quite a few differences between Windows XP Professional and Windows XP Home. Here is a list of specific features available in the Professional edition:

• Supports two CPUs
• Supports roaming profiles
• Supports Remote Desktop and Remote Assistance
• Has Computer Management and Performance Monitor.
• Supports joining a Windows-based server domain
• Allows Group Policies with users. which allow you to customize user and computer accounts
• Provides Encrypting Files System (EFSI
• Supports dynamic disk support allowing you to increase the size of a partition
• Supports IPSec (lP Security). which allows you to secure and encrypt TCP/IP data
• Upgradeable from Windows 98. Windows NT, Windows ME. or Windows 2000 Professional

Here is a list of specific features available in the Home edition:

• Supports only one CPU
• Supports only Remote Assistant
• Upgradeable from Windows 98 and Windows ME

Windows XP Professional supports 32-bit Windows applications, 16-bit Windows applications, and some DOS applications (only those that do not access hardware directly). Every 32-bit application runs in its own 2 GB memory space. Alll6-bit Windows applications run in a single virtual machine. A virtual machine simulates a single computer with its own memory, hardware devices, and software configuration.

DOS and 16-bit Windows applications run in a single 2 GB memory space. The Windows XP VMM (Virtual Memory Manager) handles allocating memory to applications. A single block, called a page, is 4 KB in size. A page is used to store files and may also retrieve a file located on a disk. This file is called a paging file.

Windcws XP supports WFP (Windows File Protection). WFP protects system files (files critical to the operating system). WFP runs in the background. When WFP detects that a file has been altered or deleted, it copies a replacement file from the WINDOWS \ SYSTEM32 \ DLLCACHE folder, from the Windows XP CD, or from a network share (a shared folder that contains a copy of the XP CD).

With Windows XP, the first screen to appear when you boot the computer is the Welcome screen. The Welcome screen allows users to log in. A user can log in to the local computer, to a workgroup (peer-to¬peer network), or to a domain (a network with a server). This has been discussed in detail in, Introduction to Networking, for more information on network types. Note that the log-in screen cannot be bypassed as it could in Windows 9x.

To log in, click on a user account icon and enter a password (if necessary) or press Ctr! + Alt + Del to go to the Log On to Windows box. Note that the local Administrator account (the master account that is allowed to change everything on the local machine) is not a user icon. You must press Ctr! + Alt + Del twice and enter the correct user id and password to use the Administrator account.