24. The method of claim 23 , further comprising: selecting a first group from the identified repeating sequences of data to encode for later decompression by a first dictionary decoder; selecting a second group from the identified repeating sequences of data to encode for later decompression by a second dictionary decoder; forming at least a portion of a compressed representation of the data stream by replacing at least one of the repeating sequences in the first group by a reference to a location in an external dictionary memory from which an uncompressed version of the repeating sequence will be accessible during decompression by the first dictionary decoder, wherein the external dictionary memory is external to the first dictionary decoder; and forming at least a portion of the compressed representation of the data stream by replacing at least one of the repeating sequences in the second group by a reference to a location in an internal dictionary memory from which an uncompressed version of the repeating sequence will be accessible during decompression by the second dictionary decoder, wherein the internal dictionary memory is internal to the second dictionary decoder.
24. The method of claim 23 , further comprising: selecting a first group from the identified repeating sequences of data to encode for later decompression by a first dictionary decoder; selecting a second group from the identified repeating sequences of data to encode for later decompression by a second dictionary decoder; forming at least a portion of a compressed representation of the data stream by replacing at least one of the repeating sequences in the first group by a reference to a location in an external dictionary memory from which an uncompressed version of the repeating sequence will be accessible during decompression by the first dictionary decoder, wherein the external dictionary memory is external to the first dictionary decoder; and forming at least a portion of the compressed representation of the data stream by replacing at least one of the repeating sequences in the second group by a reference to a location in an internal dictionary memory from which an uncompressed version of the repeating sequence will be accessible during decompression by the second dictionary decoder, wherein the internal dictionary memory is internal to the second dictionary decoder. 27. The method of claim 24 , wherein the first group of repeating sequences is selected so that, for each instance of a repeating sequence in the first group, the sum of the number of bits making up the uncompressed version of the repeating sequence and the number of bits occurring between the instance and a preceding instance of the same repeating sequence in the stream of data is higher than a predetermined reference value; and the second group of repeating sequences is selected so that, for each instance of a repeating sequence in the second group, the sum of the number of bits making up the uncompressed version of the repeating sequence and the number of bits occurring between the instance and a preceding instance of the same repeating sequence in the stream of data is equal to or lower than the predetermined threshold value.