If there was any doubt that the battle for the future of computing is hitting a new high, Monday’s announcement from Microsoft of the new Surface tablet has put that to rest. The company has broken from its traditional path of only producing the software and letting its partners produce the hardware. This is a Microsoft device through and through.

We have, of course been here before. The late Zune was Microsoft’s answer to iPod and Windows Phone 7 its response to iPhone. One is throughly dead, and the jury is still out on the other. Their only major foray into computing hardware that has been an unqualified success is the XBox games console, which continues to dominate the current generation of consoles, while acting as Microsoft’s trojan horse into the living room.

So which is the Surface to be? Another failed attempt by Microsoft to match an Apple success? Or a Windows or XBox-like late arrival that comes to dominate the market?

The stakes have never been higher. Mobile devices are becoming the gateway to desktop purchases. Phil Libin of Evernote made it clear during his run-down of Evernote’s revenue at Le Web London this week that people who come to his product through mobile go on to the desktop apps. If tablets are beginning to shape desktop-buying habits – and corporate ones in particular, then Microsoft has a problem.

By announcing this likely-unfinished product now, Microsoft has every chance of putting a hold on at least some corporate buying decisions. IS managers, under pressure from board members and employees alike, have been forced into looking at the issues around iPad deployment. From more open WiFi networks, to the growing bring your own device trend, new ways of looking at corporate IT are emerging. For Microsoft, which has derived the majority of its revenue from corporate Windows and Office deals, that is a serious threat. For IT managers used to working in a Microsoft-centric environment, it’s an uncomfortable shift.

Now, however, they can argue hard for a pause in any further expansion of iPad programmes, because the Microsoft Surface has the potential to more easily integrate with their existing infrastructure, and familiar Office apps. I’d imagine Microsoft’s sales people will be out and about amongst corporates making that very message clear. The tablet has largely been a consumer product up until now. The battle for dominance in the corporate space is only just getting underway. Apple has the early lead, and Microsoft has announced its entry in the game. The chances are we’ll see Google’s “market leading” tablet that Eric Schmidt talked about six months ago at Google I/O shortly. Tablets are the mass-market computers of the future, and Microsoft has the most to lose.

The detail-lacking announcement on Monday was far less about selling Surface tablets than it was about stopping iPad (and possibly Android tablet) sales. It was a defensive measure before the big assault begins. And it will be a big assault. In the past, corporate experiences have driven personal IT purchases. If you use and are familiar with a Windows-based PC at work, you’re more likely to buy a Windows machine for home. The iPad is beginning to reverse that – people are changing their working habits based on a device they bought for themselves. This is a battle that Microsoft cannot afford to lose.