12. A data compressor which compresses a digital stream of data, the compressor comprising: an encoder which matches strings of digital data with fixed size code words; a transmitter coupled to the encoder which sends the fixed size code word; a memory coupled to the encoder to store a dictionary with nodes representing strings of digital data, the fixed size code word and an index relating to the frequency that the fixed size code words are sent, wherein the fixed size code words are deleted from the dictionary as additional fixed sized code words are added; and a processor which, when a string is matched, creates a copy of the node representing the string, creates a new node to store the copy of the node, and deletes the node representing the string from the dictionary.
12. A data compressor which compresses a digital stream of data, the compressor comprising: an encoder which matches strings of digital data with fixed size code words; a transmitter coupled to the encoder which sends the fixed size code word; a memory coupled to the encoder to store a dictionary with nodes representing strings of digital data, the fixed size code word and an index relating to the frequency that the fixed size code words are sent, wherein the fixed size code words are deleted from the dictionary as additional fixed sized code words are added; and a processor which, when a string is matched, creates a copy of the node representing the string, creates a new node to store the copy of the node, and deletes the node representing the string from the dictionary. 13. The data compressor of claim 12 wherein the memory includes a linked list with entries to record nodes in the order they are used to represent subsequent strings of data; and wherein the entry relating to a node is updated by moving the entry to the start of the linked list when the node is used.