Western Digital has now officially purchased flash memory manufacturer SanDisk after regulator approval was passed earlier this week. The agreement between the two storage companies was originally announced last October in a deal worth nearly $19 billion. However, Chinese company Unisplendour, which was planning to buy a 15 percent stake in Western Digital as part of the merger, backed out in February this year, lowering the value of the deal to around $16 billion. At the time, Western Digital reaffirmed its confidence in the purchase, and this week said it was looking forward to creating "the leading storage solutions company."

Western Digital's chief executive Steve Milligan described the deal today as a "transformational combination," creating a "a media-agnostic leader in storage technology." Up till now, Western Digital's business had been focused on regular hard disk drives, but these are slowly becoming obsolete as speedier and more reliable solid state drives (like those built by SanDisk) become cheaper. Buying SanDisk isn't exactly "transformational" for Western Digital (it's still a digital storage company after all), but it is necessary if the company wants to stay relevant.