Microsoft Surface sales were on the up-and-up during the first quarter of 2013, according to IDC. The research firm found that Microsoft is moving up the ranks as a serious tablet manufacturer, and the Surface Pro and Surface RT tablets combined for a total 900,000 units shipped during the first quarter.\u00a0The Surface sales placed the Redmond-based company with a 1.8 per cent tablet marketshare for the quarter, letting Microsoft enter fifth place in this category for the first time. Microsoft was beneath the leader Apple, followed by Samsung, ASUS and Amazon, all of which are regulars on the top five list. Apple, of course has its iPad, while Samsung continues to push its Galaxy Tab and Note line, and ASUS sells the Nexus 7 among other budget tablets.An interesting factoid from IDC is that the more expensive Surface Pro made up a large amount of the 900,000 total Surface units. The Surface Pro first went on sale in the U.S. and Canada in February, and Microsoft has plans to expand it even further across the world to 25 countries in May, in the hope of adding marketshare.Beyond the Surface tablets, Windows and Windows RT tablets failed to gain traction, according to the IDC, and total combined sales for the two mobile operating systems reached 1.8 million units. An IDC program manager further commented on the notion that a 7-inch tablet would be Windows' saving grace, saying that wouldn't be the case.\u00a0\u00a0In March, Dina Bass of Bloomberg claimed Microsoft sold 1 million Surface RT and 400,000 Surface Pro units to date.\u00a0It's not clear where these numbers came from specifically, so take it with a grain of salt.Total tablet shipments from all companies grew an impressive 142.4 per cent year on year in Q1 2013, sitting at 49.2 million total units, passing the whole first half of 2012. Increased market demand for smaller screen devices was pointed out as one of the reasons tablet sales show no signs of slowing down.The 7-inch tablet that instantly comes to mind is Apple's iPad mini. Last week, the Cupertino-based company reported that it sold a whopping\u00a019.5 million full-sized iPads and iPad minis (compared to 11.8 million in the same quarter last year). Given that Q1 is usually a slow time for sales,\u00a0Apple turned it around and increased iPad sales 66 per cent on the year, making for its second highest tablet sales ever.On Monday, BlackBerry CEO Thorsten Heins claimed there would soon be no demand for tablets at all. Given the increased rate at which tablets are selling, we find Heins's comments a little confusing.