Microsoft presented a proposal regarding this at the WinHEC show. Microsoft said that they have started talking with hard drive makers to redefine how hard drives access data. The upgrades would require flash memory to be built in or alongside hard drives to minimize the time a PC needs to access the drive.
While desktop customers value speed, laptop users are more likely to try and postpone connecting to a power cord. Although notebook PC OEMs often look to the CPU and display as the chief power draws, spinning up a rotating hard drive can also drain batteries quickly. Using Microsoft Word, for example, consumes more power than running the MobileMark laptop benchmark, Microsoft's tests found.Source: PC Mag
Microsoft is proposing embedding a NAND flash chip in or near the hard drive to serve as a write buffer, in conjunction with "Longhorn", Microsoft's next-generation operating system.