We present Subversion Statistics Sifter, a visualisation and statistics system for exploring the structure and evolution of data contained in Subversion repositories with respect to both developer activity and source code changes. We support a variety of visualisation techniques, including statistical graphics and graph plots. We exploit the inherent hierarchical structure of software archives ...

To support the increasing number of sensor devices with various characteristics and requirements, sensor network operating systems should provide an appropriate device driver model that can cover a wide range of device types. Unfortunately, current sensor network operating systems force the user to build complex drivers for even simple devices, provide restricted interfaces, or do not provide a...

Part of the difficulty in constructing highly available services is that a modern Internet service is mind-boggling in complexity. The application, database, operating system, and firmware contain thousands of interfaces and millions of lines of code. Worse, unlike many other highly available systems, the major components are created by different organizations with potentially different goals a...

of output produced per unit of input. While it is easy to define, it is notoriously difficult to measure, especially in the modern economy. In particular, there are two aspects of productivity that have increasingly defied precise measurement: output and input. Properly measured, output should include not just the number of widgets coming out of a factory, or the lines of code produced by a pro...

We present an analysis to verify abstract set specifications for programs that use object field values to determine the membership of objects in abstract sets. In our approach, each module may encapsulate several data structures and use membership in abstract sets to characterize how objects participate in its data structures. Each module’s specification uses set algebra formulas to characteriz...

We have designed and implemented an optimizing source-tosource C++ compiler that reduces the frequency of virtual function calls. Our prototype implementation demonstrates the value of OO-specific optimization for C++. Despite some limitations of our system, and despite the low frequency of virtual function calls in some of the programs, optimization improves the performance of a suite of large...

Cryptic type error messages are a major obstacle to learning OCaml or other ML-based languages. In many cases, error messages cannot be interpreted without a sufficiently-precise model of the type inference algorithm. The problem of improving type error messages in ML has received quite a bit of attention over the past two decades, and many different strategies have been considered. The challen...

McCabe’s cyclomatic complexity metric is widely cited a s a useful predictor of various software attributes such a s reliability and development effort. This critique demonstrates that it is based upon poor theoretical foundations and an inadequate model of software development. The argument that the metric provides the developer with a useful engineering approximation is not borne out by the e...

This paper describes our experiences building a secure rlogin environment. With minimal changes to the rlogin server and the use of a secure network layer protocol, we remove the vulnerability of hostname-based authentication and IP source address spoofing. We investigate how applications such as rlogin interact with this new layer, and propose extensions to the rlogin server that can utilize t...

The structure of a large system can be made comprehensible if it can be viewed as a modest number of interacting entities. For example, the 800,000 line Linux kernel can be reasonably viewed as its five top-level interconnected subsystems. Each abstracted entity (subsystem) may have aggregated attributes, e.g., the total count of the number of lines of code in it, or the set of programmers who ...