LZ77 and LZ78, two dictionary-based data compression techniques described by these two researchers, provided a whole new way of viewing the world of data compression. Both algorithms are based on the principle of storing pointers to the data. The pointers make references to phrases which have made previous appearances. It is important, however, to note that LZ77 and LZ78 are distinct. Lempel and Ziv's compression techniques of '77 and '78 gave rise to a series of variants which form part of the LZ family .
Variations have to do with factors such as establishing how many bits to use for certain boundaries.
As an example, the zip and unzip methods use the LZH techique. UNIX compress methods, on the other hand, belong to the LZW and LZC classes. Disputes over patenting have actually slowed down the evolutionary progress of the LZ method. To illustrate the LZ compression technique, we take a simple alphabet containing only two letters, a and b, and create a sample stream of text. Separate this stream of characters into pieces of text so that the shortest piece of data is the string of characters that we have not seen so far.