Method and apparatus for enhancing data storage efficiency

A method for enhancing data storage efficiency by aging data in a memory system including a base set and a heap, where at least a portion of said heap is subjected to a periodic garbage collection routine, said method comprising the steps of:

• a. chronologically grouping data comprised of datum which is stored within said heap into a plurality of segments including a new heap having a first designated logical memory space where new data is created, an aging heap which has a second designated logical memory space which is contiguous with said first designated logical memory space for data which has survived at least one garbage collection routine, and a stable heap having a third designated logical memory space which is contiguous with said second designated logical memory space for data which has survived a greater number of garbage collection routines than said aging heap and which is no longer subjected to routine garbage collection, where the boundary between said first designated logical memory space and said second designated logical memory space is designated by a first pointer and where the boundary between said second designated logical memory space and third designated logical memory space is designated by a second pointer, wherein the age of a datum within said heap is imprecisely determined by its inclusion within said new heap, said aging heap or said stable heap rather than by a specific age associated with said datum;
• b. selectively performing said garbage collection routine by removing datum from said new heap and said aging heap which is neither directly nor indirectly referenced by pointers stored within said base set, and by not removing datum from said stable heap;
• and
• c. repeating steps a. and b.

A virtual memory system for enhancing data storage efficiency comprising:

• primary memory means and secondary memory means, said primary memory means and said secondary memory means collectively including a multiple page base set area and a heap area, where said base set area has references to said heap area;
• primary dirty page map storage means which is capable of being cleared;
• save state map storage means;
• secondary dirty page map storage means which is capable of being cleared;
• means responsive to said primary memory dirty page map storage means and said secondary memory dirty page map storage means for effectively reducing said base set area for garbage collection purposes by determining which pages within said base set area have not been written to since said primary dirty page map storage means and said secondary dirty page map storage means were last cleared;
• garbage collection means responsive to said reduced base set area and operative to remove un-referenced data from said heap area;
• and
• virtual memory means responsive to said primary dirty page map storage means and said saved state map storage means and operative to manage said primary memory means and said secondary memory means.