Back to the future: a retroactive study of aspect evolution in operating system code

The FreeBSD operating system more than doubled in size between version 2 and version 4. Many changes to primary modularity are easy to spot at a high-level. For example, new device drivers account for 38% of the growth. Not surprisingly, changes to crosscutting concerns are more difficult to track. In order to better understand how an aspect-oriented implementation would have fared during this evolution, we introduced several aspects to version 2 code, and then rolled them forward into their subsequent incarnations in versions 3 and 4 respectively. This paper describes the impact evolution had on these concerns, and provides a comparative analysis of the changes required to evolve the tangled versus aspect-oriented implementations. Our results show that for the concerns we chose, the aspectoriented implementation facilitated evolution in four key ways: (1) changes were better localized, (2) configurability was more explicit, (3) redundancy was reduced, and (4) extensibility aligned wi...

• Type: Conference
• Year: 2003
• Where: AOSD
• Authors: Yvonne Coady, Gregor Kiczales
• Keywords: AOSD 2003, Aspect-oriented Implementation, Many Changes, Software Engineering, Version 2