Experiences in using Optimisitic Locking in Fujaba.

1. REQUIREMENTS ON VERSIONING In software engineering, we have profound experiences in using versioning systems for textual programming languages. For small teams one might use versioning systems with pessimistic locking like SCCS or RCS. This means, changing files is mutally exclusive. On larger teams, such pessimistic locking approach runs into problems, when more frequently multiple users need write locks on multiple files. To overcome these limitations, versioning systems with optimistic locking, such as CVS [4] or SVN [5], have been introduced. These systems allow for concurrent changes on multiple local copies of the same file. The assumption is, that different users will most likely modify disjunct parts of the file and that merging these changes will work smoothly. Before a change can be committed to the central versioning repository, the user has to merge changes already committed by other team members into his local copy. If the diffent users have modified distinct parts of the file, only, these changes will be combined in the optimistic assumptions that they do not interfere.