The tablet wars are hotting up again. Since the iPad launched, back in 2010, most of the skirmishes have been taking place in the consumer world, with Apple trouncing its opponents over and over again.
But this year the fight moves onto the corporate battlefield, where the outcome is going to be far less certain, even though the stakes are just as high.
Apple's sales to business certainly seem to be growing, fuelled by the iPad and iPhone effect: businesses are likely to spend $16bn on iPads and $12bn on Macs in 2013 - in comparison to the $6bn they spent on each last year, according to figures from Forrester Research.
And while that's still dwarfed by the $68bn that will be spent on Windows PCs and tablets in 2013, it's a significant increase in spending on Apple by businesses and government.
More than half of tablets - 55 per cent are bought by consumers right now, according to Gina Luk, senior analyst at analysts Strategy Analytics, while sales to business account for only about 10 per cent of tablets sold.
But the real surprise is that 35 per cent to 40 per cent of tablets are being sold to consumers for them to use at work. The implications are that while workers see tablets as a worthwhile business tool, their employers are reluctant to spend money, restricting themselves, at least for now, to modest trials and pilots.
Luk expects tablet deployment and adoption will gain momentum in 2012, with the proportion of tablets being bought by businesses growing to around 18 per cent to 20 per cent by 2015, as the number of business applications available on tablets increases.
So far the vast majority of the tablets being used in business are iPads: Apple has had no real competition in the business market, despite the huge number of Android tablets and the modest number of Windows 7 tablets available.
But Microsoft's tablet-friendly Windows 8 is likely to be released later on this year, at which point the real battle could start.
Windows 8 tablets
"It depends on Microsoft's go to market strategy for Windows 8. People are still very much keen on iPads and even for RIM's PlayBook, the take-up was not as much as we expected, so Microsoft will have to push very strongly if they want to be successful with Windows 8," warns Luk.
My prediction is that Microsoft will fight back hard, because this time it really has to. Until now tablets have been consumer playthings and executive toys, which is why Microsoft has been reasonably relaxed about Apple's growth in business.
But tablets are now being considered as genuine business devices, and the way that iOS and (to a lesser extent) Android devices are seeping into business will undoubtedly be worrying.
That's because tablets, smartphones and laptops are no longer standalone devices. The smartphone you buy will influence the type of tablet you buy. And the type of tablet you buy will influence the type of laptop you buy. Which means if your customer chooses a smartphone or a tablet from a rival, you might lose their laptop budget, too.
For want of a nail, the kingdom is lost, as the proverb goes.
Google, Microsoft and Apple, each with different strengths, weaknesses and motivations are encouraging us to buy into their ecosystem, and their ecosystem alone. So that's why iPhone, iPad and Mac, are lined up against Android phone, tablet and Chromebook, and against Windows Phone, Windows 8 tablet and laptop. It's no longer good enough for these companies to be strong in one of these areas - they want to be the sole supplier across all these devices through which we access our digital lives.
As Ovum analyst Tony Cripps puts it: "Tablets are just part of a bigger phenomenon. The device is used as the point at which you capture and control an ecosystem, and that ecosystem is not just application developers but also content providers and end users."
He adds: "If by creating an integrated experience - services, content and applications that run across all of those devices simultaneously - you create a better experience for the end user... they will invest more in that platform. If you are a company like Microsoft or Apple or Google there are many reasons why you might produce a standardised application platform and operating system that runs across a whole range of devices."
That's why these three different battles for supremacy in the smartphone, tablet and desktop world are really just part of a bigger war for control. Lose the tablet battle and you risk losing the bigger war.
Business plays the waiting game with tablets
Right now, many businesses are holding back, waiting for Windows 8, before they make a decision whether to roll out tablets more widely. One of the benefits of waiting for Windows 8 is that IT departments are - generally - much more familiar with Windows and it will integrate more easily with their existing infrastructure. Meanwhile, consumerisation of IT is undermining the old certainties about who decides what hardware gets bought and used for work.
That's why Windows 8 tablets are going to be - or at least should be - so important for Microsoft, if it really wants to provide a comprehensive offering of smartphone, tablet and desktop to businesses. Plus, Microsoft has the home advantage in that most organisations will already be heavily dependent on its desktop technology.
And yet for all this, the big question is - how hard is Microsoft going to push Windows 8? Ovum's Cripps points out that for Microsoft this is just one business among many others, including enterprise software and gaming, and as such, he wonders: "Are its motivations for succeeding as powerful as those for those other companies? If it's not successful maybe that goes some way towards explaining why, because it wasn't so necessary for it."
No doubt Google and Apple will hope that Microsoft will be focusing on other things than tablets, but I think we're more likely to see fireworks.
Steve Ranger has nothing to disclose. He does not hold investments in the technology companies he covers.
Steve Ranger is the UK editor-in-chief of ZDNet and TechRepublic. An award-winning journalist, Steve writes about the intersection of technology, business and culture, and regularly appears on TV and radio discussing tech issues. Previously he was the editor of silicon.com.