Microsoft spells out Win64 apps strategy

ALTHOUGH MICROSOFT has not finally committed to every feature in its up-and-coming Windows XP for X64, it has shown off its OEM partners a preliminary features list.

Reassuringly, according to sources close to Microsoft's plan, it is saying that a single binary version of Windows for X64 will support both AMD64 and Intel's EM64T architectures. This confirms statements made by Intel CEO Craig Barrett earlier this year, and indicates that our dubbing of the instructions as iAMD64 is perfectly appropriate, if a little teasing.

Quite a few applications will run on Windows XP64 using WOW64, a way of supporting 32-bit apps for machines supporting iAMD64..

Those include Microsoft Operations Manager 2005, which will include a 64-bit agent, Office 2003, Office XP, Project and Visio.

Some games will use WOW64 such as Fright Stimulator, Age of Empires and Age of Mythology. Other apps including Microsoft Streets, Digital Image Suite, and and Microsoft Plus Digital Media Edition will also use WOW64.

As you'd expect, Win64XP pretty largely mirrors the current Windows XP, but it's pretty clear that it will also build in some features of SP2 when that's released.

The list includes Windows Security Centre, DVD video playback, Bluetooth, Open GL, DirectX 9, power management equivalent to 32-bit XP and other bits and bobs like fast user switching, system restore, home networking and the like.

What we can't expect is support for Microsoft DOS, 16-bit, OS/2 subsystems, POSIX or legacy transport protocols.

Goodbye DOS. Sixty four bit Windows won't run 16-bit code and so 16-bit installers could be tricky too. However, if there's a 32-bit installer, Windows will seek it out and run it.

As far as 32-bit file system filter drivers and kernel mode drivers are concerned, Win64 XP will need them to be native - that means that 32-bit kernel system drivers will fall over.

The developer kits from Microsoft contain compilers but these are in a pre-release stage, and only available through the Vole's technical beta programmes - while a DirectX 9.0 SDK update will support 64-bit development on X64 systems for multimedia applications.

Whidbey - Microsoft's Visual Studio 2005 - will install on both 64-bit and 32-bit versions of Windows, and will include 64-bit tools such as the common language runtime and .net framework. When that's released, the compilers will be able to produce code which is 32-bit or 64-bit only.

But Microsoft has changed its mind about the 32-bit .net framework. It had formerly indicated that the 32-bit .net framework wouldn't work in WinXP 64. It has changed its mind.

Microsoft is warning device manufacturers to check that all their drivers will work on 64-bit Windows - users are going to expect everything to work seamlessly.

Well yes, we always expect that, but there's always been problems with this sort of stuff in the past. µ

See Also
Microsoft votes for X64 support over Intel Itanium
Microsoft confirms Windows XP will be OEM only

L'INQ
Route64.net