simply download the new patch and the older version is updated to the current version. We analyze the patch files to obtain the same detailed metrics on each patch. We developed a tool to count the number and type of modules being added, deleted or updated in a newer version. We validated our tool against files of known modules and changes. We also developed a tool to count the number of corrective, adaptive or perfective maintenance from the change logs. So far a total of 29580 patches has been analyzed in the 21 releases.
200 180 160 140 120 100
80 60 40 20
0
1 3 5 7 9 11 13 15 17
Maintainers
Size
Figure 2: Growth of size and maintainers in Linux
Prior research has shown that Linux exhibits super linear growth [5]. Our analysis indicated that the increase in size is accompanied by a proportional increase in the number of maintainers, as shown in figure 1. Thus the quality is maintained because an increase in size of the software is accompanied by an increase in the effort expended in maintenance.
As explained earlier, we believe that he importance of the quality carrying characteristics will be dynamic in OSS. Since there is no means to capture conformance to user requirements or user satisfaction, for Linux we operationalize software quality in terms of Software Maturity Index (SMI), as defined by IEEE std.982.1- 1988. SMI provides an indication of the stability of s software product. As SMI begins to approach 1.0, software product begins to stabilize. Preliminary results on testing of our model will be ready for presentation at the workshop.