David Fotland said: > I used 8x8 bit map and a 8 bit hash table....... If 8 bit hash is more efficient than 16, 32, or 64 bits (is it with a 32 bit bus and cpu?), I have a suggestion. Why not use multple hash tables. The first table is 8 bit. The second is 16 bit, and so on. Only those passed the first table are checked with the next table. Dan Liu