Parallel changes in large scale software development: an observational case study

An essential characteristic of large scale software development is parallel development by teams of developers. How this parallel development is structured and supported has a profound effect on both the quality and timeliness of the product. We conduct an observational case study in which me collect and analyze the change and configuration management history of a legacy system to delineate the boundaries of, and to understand the nature of, the problems encountered in parallel development. The results of our studies are: 1) that the degree of parallelism is very high-higher than considered by tool builders; 2) there are multiple levels of parallelism and the data for some important aspects are uniform and consistent for all levels and 3) the tails of the distributions are long, indicating the tail, rather than the mean, must receive serious attention in providing solutions for these problems.