1 This supports the presence of distinct primary and secondary memory stores rather than a unitary system.

2 Secondary memory holds the information that you store in the computer.

3 Secondary memory has two features that can not be provided by RAM memory.

4 With current memory prices, swap space represents a very slow secondary memory.

5 A great number of spatial indexing structures based on secondary memory have been proposed for handling the massive spatial data stored in the spatial database rapidly and efficiently.