The document indicates that Microsoft filed the patent application initially on October 21, 2004 and followed up on February 5, 2009 and May 6, 2010. The most recent continuation was submitted by Microsoft in July of this year in what appears to be an ongoing process to get the invention approved.
Described as "using external memory devices to improve system performance", the document relates to a feature that was heavily marketed during the launch of Windows Vista and is still available (opens in new tab), but is largely forgotten by mainstream users today. According to the patent application, the invention covers external memory storage devices that integrate volatile or non-volatile solid-state memory. The idea is to use such a drive "to cache sectors from the hard disk (i.e., disk sectors) and/or slower memory components to improve system performance."
According to the data published, Microsoft found that data read times could be accelerated by more than 60 percent in some circumstances with this technology.