Consistency maintenance is one of the most significant challenges in the design and implementation of the systems, where a group of users is allowed to view and edit the same document at the same time. From geographically dispersed sites connected by communication networks Operational transformation (OT) is an established optimistic consistency control method in collaborative applications. In addition, they generally support two character-based primitive operations, insert and delete, in a linear data structure. This paper presents an integrative review of the evolution of operational transformation techniques. It discusses major issues, algorithms, achievements and remaining challenges. A comparative study is done of various algorithms of OT based on different parameters.

Operational transformation (OT) Inclusion and Exclusion transformation dOPT TP2