Windows XP comes in four varieties: Home Edition, Professional Edition, Embedded and 64-Bit. XP Home and Professional will officially ship on 25 October, although you'll be able to buy systems with it pre-loaded before that, with Embedded and 64-Bit expected shortly afterwards.
XP Home Edition is expected to be the most common. It's the basic version that includes support for audio, video and picture editing, and it will work much like Windows ME. As the name suggests, XP Home is aimed at single computers or networks at home or in the smaller business. It runs practically all existing Windows applications and has support for several thousand peripheral devices. It's also quite good at sharing a single computer among multiple users: you can switch from one desktop to another while keeping track of the state of all software and data, and you can set different privileges for things like Internet access for different users. It also comes with a personal firewall.
XP Professional is a superset of these features, including many functions first seen in Windows 2000. Like Windows 2000, it's aimed at companies, both for desktop and server services. If you're used to running NT you'll find the core capabilities of XP Professional familiar: it includes such things as IntelliMirror, which lets you run what looks like your desktop on a different computer. XP Professional also has desktop settings and software administration for corporate networks, policy management for group and local desktops, a personal Web server, remote desktop access for debugging and training, dual processor support and more advanced security including an encrypting file system and file-level access control.
|What's unique in XP Professional?|
|Remote Desktop ||access an XP Professional system from another Windows PC|
|Offline files and folders ||access files and folders on a network share when disconnected from the server|
|Scalable processor support ||up to two processors|
|Encrypting file system ||protects sensitive data in files stored on disk using NTFS|
|Access control ||restrict access to selected files, applications and other resources|
|Centralised administration ||join XP Professional systems to a Windows Server domain|
|Group policy ||simplifies the administration of groups of users or PCs|
|Software installation and maintenance ||automatically install, configure, repair or remove applications|
|Roaming user profiles ||access all your documents and settings wherever you log onto the network|
|Remote Installation Service (RIS) ||remote OS installations where desktops can be installed across the network|
|Multi-lingual User Interface (MUI) add-on ||change the user interface language to get localised dialogs, menus, help files, dictionaries and proofing tools|
| If you're used to running NT, you'll find XP Professional's core capabilities familiar.|
Embedded XP -- currently in beta -- is part of Microsoft's policy of providing an alternative to Linux in all markets. It's the same core code as full XP, but features can be removed to reduce the operating system's size. An absolutely stripped down version will run in 5MB, although Microsoft says that it will take closer to 35MB to provide the services that most products are likely to use. Like Windows NT, XP isn't a real-time operating system -- if you need that, you either add it yourself or use a different OS. Embedded XP is aimed at set-top boxes, point-of-sale terminals, cash-points and other larger computerised products. Microsoft is trying to build a developer community around Embedded XP, as it considers this to have been instrumental in Linux's success in this market.
Embedded XP will also have to co-exist with Talisker, the next development of Windows CE, which is also being pushed heavily as an embedded OS. Unlike XP, Talisker includes Bluetooth support; Talisker is also smaller, better suited to battery devices and has superior support for real-time events. Both OSs have .Net capabilities.
Windows XP 64-Bit Edition, also in beta, is aimed at very demanding applications such as animation, engineering simulation and scientific modelling. It runs on Intel's 64-bit Itanium processor, and will work with future IA-64 instruction set processors. The most significant changes from 32-bit Windows are its ability to handle much more memory -- 16GB of physical RAM and up to 16 terabytes of virtual memory -- and floating-point operations optimised for the processor. Otherwise, it will look and feel much like other members of the XP family. Microsoft says that most 32-bit code will run 'as-is' in a subsystem in XP 64-Bit, and that most of the features of 32-bit XP are carried across, but that any task requiring less than around 2GB of memory may be better suited to the 32-bit versions of the operating system.