The wear and tear, fragmentation on HDD can be reduced using a Tripod Hybrid. Access Speed improves too...
Top Layer is RAM Drive with Li-ion Battery. Second layer is Flash. Third is the Spinner HDD.
All active files of user are on RAM drive and backed up on Flash by intelligent Drive (not CPU). The files go into HDD after they have been stable for over an hour. As HDD sizes are increasing. The files and file system can be like svn and maintain 3 versions of all dynamic files. This is useful for user also and HDD too.
Static files like Binaries can be on one area of HDD. Frequently accessed binaries are promoted to flash layer. Extremely frequent to Ram Layer. The HDD now is less stressed and lasts longer and is a stable backup. Power failures immune.
A supercap built into a HDD. On Brownout OR Power Fail. The falling ramp is detected beyond an isolating diode. It says to HDD uC ... Look there is something funny with power now. The HDD uC at once finishes the work at hand, drawing its juice from the stable supercap, parks its heads and goes to sleep.
When power is stable again, it wakes up and the supercap is replenished too. This way damage to HDD is avoided, these happen when .. battery connection problems in laptop or mains power fluctuations or switching power systems carelessly. It makes HDD idiot proof at least electrically.
- delabs 2009