Apparatus and method for comparing data groups

A method for identifying and displaying the differences between first and second documents, said documents comprising groups of alphanumeric characters including words, lines and sentences comprising the steps of:

• storing each of said documents in a memory;
• generating hash numbers from said lines and sentences of each of said documents, such that identical lines and identical sentences produce identical corresponding hash numbers;
• comparing hash numbers generated for said first document with hash numbers generated from said second document;
• creating lists of anchorpoints in said memory, said anchorpoints representing matching hash numbers from each of said documents;
• defining blocks of identical text in both documents containing at least one anchorpoint;
• defining difference blocks of text not contained in said identity blocks;
• storing in memory the location in each document of said identity and difference blocks;
• classifying said identity and difference blocks into one of a plurality of classifications and storing said classifications in memory;
• displaying said identity and difference blocks and said classifications.

In a computer controlled display system having a display wherein first and second groups of characters are simultaneously displayed and differences between said first and second groups are indicated on said display, a method for displaying said groups and said differences comprising the steps of:

• generating and displaying said first group of characters on a first region of said display;
• generating and displaying said second group of characters on a second region of said display;
• controlling the scrolling of said first and second regions so that the group of characters in said second region correspond to the group of characters in said first region;
• determining differences between said first and second groups of characters;
• generating and displaying indicators in said first and second regions, said indicators identifying said differences between said first and second groups of characters;
• whereby said first and second groups of characters and said differences are displayed.