Back in 2006, storage tech talk was intermittently buzzy with a few different innovations. One was wrapped around the pending release of Windows Vista, particularly two bullets on its feature list: ReadyBoost and ReadyDrive. In parallel with all of the Ready_____ talk, many tech pundits asked why it would be necessary to have the flash talk to Windows through special drivers. Why couldn't the flash memory just act like a larger RAM cache already present on?
A prototype ReadyBoost-enabled HDD by Samsung.
The answer, which nobody was aware of at that time, was that management of flash memory was a tricky thing to do successfully. It would not be until several years later that SSD's would (mostly) beat the issues of Long Term Performance and other issues that crop up when attempting to store randomly written data onto a device that can only be erased in relatively large blocks.
ReadyDrive required a special 'Hybrid' disk drive to be connected to and recognized by Windows Vista, containing both spinning platters and flash memory. Vista would then place frequently used small files on the flash. Since flash memory has negligible access times when compared to seek times of a HDD, the drive overall would boot significantly faster. Other tasks using those cached system files also saw a benefit. While ReadyDrive looked great on paper, there were very few devices ever released that could take advantage of it. Seagate was the earliest to release such a drive, and their Momentus 5400 PSD laptop drive did not see the light of day until Vista was nearly a full year old.