>What does "outside-of-memory" data compression algorithm mean, exactly? You keep your data structures (dictionary, Huffman tree, etc.) in storage and stream t

>What does "outside-of-memory" data compression algorithm mean, exactly? You keep your data structures (dictionary, Huffman tree, etc.) in storage and stream them into memory only as necessary. Same for the data being compressed. You could use an extremely large dictionary while only using a few kilobytes of memory.