Abstract: Method and apparatus for comparing original and modified versions of a document. The system of the present invention utilizes a hash number generator CPU to generate hash numbers for lines and sentences contained in the documents. Matching hash numbers are defined as anchorpoints and stored in an anchorpoint memory. A comparator CPU performs a character-by-character comparison of the respective documents radiating outward from each anchorpoint. This comparison generates identity blocks which are defined as blocks which are the same in both documents. Non-identity blocks are defined as difference blocks and are characterized as insertions or deletions depending on their status. A portion of the original and modified document is displayed in a split-screen format on a display, such as a CRT. Cursors on the top and bottom half of the screen identify corresponding portions of the documents.

Abstract: Method and apparatus for comparing original and modified versions of a document. The system of the present invention utilizes a hash number generator CPU to generate hash numbers for lines and sentences contained in the documents. Matching hash numbers are defined as anchorpoints and stored in an anchorpoint memory. A comparator CPU performs a character-by-character comparison of the respective documents radiating outward from each anchorpoint. This comparison generates identity blocks which are defined as blocks which are the same in both documents. Non-identity blocks are defined as difference blocks and are characterized as insertions or deletions depending on their status. A portion of the original and modified document is displayed in a split-screen format on a display, such as a CRT. Cursors on the top and bottom half of the screen identify corresponding portions of the documents.