With Windows 10, Microsoft is trying to turn the tide against the proliferation of operating systems across desktops, servers, tablets and smartphones by creating a single operating system that will run on them all.

Currently the world’s billions of Windows users are spread across its older versions, with Windows XP, released in 2001, still boasting the same installed base of users (around 12% market share) as the two-year-old Windows 8.1 (at 13%). The bulk of Windows users (61%), are still using Windows 7, released in 2009. And that’s not to mention the various incompatible Windows versions designed for tablets or smartphones.

Trying to consolidate different versions isn’t a new idea, although it’s much easier said than done. Recent versions of Apple’s Mac OS X operating system for desktops and laptops have drawn inspiration from iOS designed for iPad and iPhone, while Canonical, the company behind the Ubuntu Linux distribution, has also produced a version for phones.

However, with Windows 10, Microsoft is taking the idea to its logical conclusion, producing not just a single OS for all devices, but a framework for apps that run on all of them, making the move between devices seamless.

One app to rule them all
If we believe the Microsoft marketing machine, this will be the start of the era of Windows universal apps. There are many clever things in Windows 10, such as the integration of the digital assistant Cortana, but universal apps are what are really exciting. This will allow developers to write code once and deploy it to all the different devices Windows 10 supports. It’s not quite as easy as Microsoft would have us believe, though: there would still need to be some code that’s written specifically for each type of device, and only some of it would be shared.

This is exciting because Microsoft is hoping to entice developers and bridge the “app gap” on Windows devices. As of May 2015, the Google Play Store has 1,5m apps, the Apple App Store has 1,4m, while the Windows Phone Store a mere 340 000. Applications, and therefore available developers to create them, are key. Getting developers on board is the best way for Microsoft to make headway in the race to get their devices into our pockets.

I’ve spent some time with the technical and insider previews of Windows 10 for the desktop. The latest builds are speedy and show a lot of promise, so much so that all of my Windows tablets and desktops are now signed up and awaiting the free upgrade. As predicted, it blends the traditional desktop experience of Windows 7 with the apps-based approach of Windows 8. It feels like a new desktop experience but is also familiar, an evolution rather than a revolution.

Enterprise focus
Some of the key improvements are less headline grabbing than a talking digital assistant like Cortana or the return of the Start menu. A key market as personal PC sales decline is the enterprise, and under the hood changes in security have been a heavy focus for Microsoft to ensure businesses are open to upgrading from Windows 7. But other than the front-end “bells and whistles” there aren’t too many obvious internal changes.

This familiarity should entice those Windows 7 users still holding out, those who found the new Metro UI interface of Windows 8.1 too much of a culture shock. Gone are the two interfaces, now merged into a single mix of traditional start menu with start screen stuck on the side. Gone, too, is the charms bar (pop-up menu) that was so heavily reliant on touch.

In another new move, Windows 10 is being given away as an upgrade for free. With successive Android, iOS, Linux and OS X updates now offered free, it was inevitable that Microsoft would eventually go the same route.

Although Windows 10 for desktop is available now, we’ll have to wait until September for the mobile version and to experiment with universal apps. Of course, it’ll be a bit longer still to see what impact a unified OS platform has, and whether Windows 10 is the fresh start Microsoft is banking on.