Both companies are currently headquartered in California and have been operating for decades. SanDisk has been a long-time partner of one of Western Digital's rivals in the storage space, Toshiba. The joint venture between SanDisk and Toshiba will apparently be unaffected by today's news. As per usual, a deal of this size needs to be okayed by various parties before it goes through -- Western Digital says it expects things to be all done and dusted by the third quarter of next year.