Hoisting C Structures Into Clay In Device Drivers

This project addresses the unreliability of operating system code, in particular in device drivers. Device driver software is the interface between the operating system and the device's hardware. Device drivers are written in low level code, making them difficult to understand. Almost all device drivers are written in the programming language C which allows for direct manipulation of memory. Due to the complexity of manual movement of data, most mistakes in operating systems occur in device driver code. The programming language Clay can be used to check device driver code at compile-time. Clay does most of its error checking statically to minimize the overhead of run-time checks in order to stay competitive with C's performance time. The Clay compiler can detect a lot more types of errors than the C compiler like buffer overflows, kernel stack overflows, NULL pointer uses, freed memory uses, and aliasing errors. Clay code that successfully compiles is guaranteed to run without failing on errors that Clay can detect. Even though C is unsafe, currently most device drivers are written in it. Not only are device drivers the part of the operating system most likely to fail, they also are the largest part of the operating system. As rewriting every existing device driver in Clay by hand would be impractical, this thesis is part of a project to automate translation of existing drivers from C to Clay. Although C and Clay both allow low level manipulation of data and fill the same niche for developing low level code, they have different syntax, type systems, and paradigms. This paper explores how C can be translated into Clay. It identifies what part of C device drivers cannot be translated into Clay and what information drivers in Clay will require that C cannot provide. It also explains how these translations will occur by explaining how each C structure is represented in the compiler and how these structures are changed to represent a Clay structure.

Effects Of Perceived Financial Accessibility Of Colleges And Universities On Studentsâ¿ Assesment Of Institutional Desirability

This study focused on the effects of socioeconomic exclusivity indicators on college students¿ attitudes toward a hypothetical private liberal arts university. Students enrolled in two undergraduate courses in Education at an elite private liberal arts university in the northeast were randomly presented with one of three versions of an admissions brochure describing a fictitious university. The three versions of the brochure varied in their portrayals of the institution¿s financial exclusivity, ranging from high exclusivity to low exclusivity. Each student was asked to review the brochure and respond to a questionnaire, containing items pertaining to the overall desirability of the institution, as well as its student culture, academic program, campus traditions, and alumni network. Based on Thorstein Veblen¿s theory of the leisure class and Pierre Bourdieu¿s theory of social reproduction, it was hypothesized that students would judge the institution most favorably in all areas under the high exclusivity condition and least favorably under the low exclusivity condition. It was further hypothesized that differences in students¿ ratings of institutional desirability would be mediated by their own financial aid statuses. Results of a two-way multivariate analysis of variance (MANOVA) revealed significant (p < .05) interactive effects of institutional exclusivity and student aid status on the perceived desirability of the academic program and campus traditions of the institution. While recipients of need-based financial aid tended to rate more socioeconomically exclusive institutions more favorably on these two variables, those who were not receiving need-based financial aid tended to rate such institutions less favorably. Implications of the findings for student affairs practice are discussed and recommendations for further research are presented.