It’s not just the way you interact with your computer that will change with Windows 8. The way programs are written is also being rethought. 

There will be two types of program running on a Windows 8 PC: legacy programs, and updated versions of existing programs. The latter will be written on the same 32bit or 64bit structure as current programs. 
Aside from a few navigational tweaks, we don’t expect to see many changes from the sorts of programs we run at present. Microsoft will include an interstitial layer to ensure this is the case.

Although the hardware requirements for Windows 8 will be modest, the only references we’ve found so far relating to how far back you’ll be able to go in terms of software suggest “applications that run on great Windows PCs today”. Windows XP users will almost certainly have to accept that they won’t be able to run programs written for it in Windows 8. Software that runs on Vista or Windows 7 should be fine, however. 

Interestingly, as we went to press, we learned of a rumoured early hardware device that will take advantage of both apps designed for touchscreens and legacy programs. The Asus Eee Pad tablet looks set to get a Windows 8 outing in 2012. 

The other sort of program you’ll find on a Windows 8 PC or laptop, however, takes a very different approach. In common with the programs being written for the web, these will use either JavaScript or HTML5 as their basis. “CSS, HTML5 and JavaScript are the most widely understood programming languages and the backbone of the internet,” says Angiulo. 

You’ll be able to have both desktop Windows applications and ones written in JavaScript running and visible onscreen at once. A shrunken Start button will act as a switch between the two modes should you prefer to use your Windows 8 PC in one rather than the other. Instant access to your world From here on, the new OS is a real departure from the product we currently think of as Windows. It is “perhaps better thought of as a mashup of Windows 7 and Windows Phone 7”, says Joanna Stern of US technology site This Is My Next. Tablet PCs may become the default form factor, and their touchscreens require a different approach. 

Windows 8 Start Screen

Unlike Google with its Android platform, Microsoft decided against tablets running Windows Phone 7. So our expectations of a built-for-tablets touchscreen interface are high. Both Apple iOS and Google Android ‘Honeycomb’ have proved impressive tablet environments and are all the better for having been built for purpose.

Importantly, Microsoft is promising the tablet-like advantages of instant-on devices, but with multitasking too. Your PC will eventually become whichever device you access it from.