Through extensive research into a harddisk's mechanical workings and the cause for mechanical defects, Quantum has developed SPS and SPS II. Both are designed to minimize damage resulting from head slaps by virtually eliminating the head's ability to move in an undesired direction. As mentioned, damage is caused when the head is allowed to lift off the disk and whip back down onto the disk, which is now prohibited.

However, Shock Protection System II, SPS II, also prevents the disk from writing data if it is dropped or shocked. In case of a shock, instead of writing the incoming data to the disk, it is stored in a buffer and written to the disk later, after the shock is over, preventing the data from being scattered across the disk to locations where it may never again be found. The below figure illustrates what happens to data being written on a disk when a shock occurs.



Fig 2. Here's how the Shock Protection System prevents the data from being written to the harddisk if the disk is shocked.

The Atlas 10K II features Shock Protection System II, which is a step up from SPS as featured on the Atlas 10K, significantly adding to its reliability. This is actually on of the few Quantum SCSI harddisks currently available that incorporates all of the noise reduction and data integrity preserving features outlined in the previous pages.