To learn about computer operating systems, students at Virginia Tech implement a command-line shell in their Computer Systems course. Successfully implementing the shell requires a deep understanding of operating system abstractions and interactions. Students often struggle with the project because subtle errors can take hours to debug.
In this work, we developed two hybrid domain-specific analysis tools to pinpoint the root causes of student errors: EshMD and ShellTrace. The EshMD tool models common errors in the shell and checks the student code against those models. To accomplish this, it monitors the specific calls the program is making and correlates those with expected changes in its environment. Students' errors are shown directly in the source code. The concept of EshMD can be applied to other programming projects by observing and modeling common bugs during implementation.
The ShellTrace tool dynamically creates a specification from a reference solution based on how the reference solution makes use of operating system resources and then uses this specification to check that a student solution is functionally identical. The ShellTrace concept can be applied to other programs that exhibit similar resource dependencies.
We deployed these tools in an undergraduate computer systems class and evaluated our tools based on the number of bugs detected and the students' perceptions of usefulness. We found that the tools detected a significant number of bugs and that the majority of students that made use of the tools found them valuable in debugging their submissions. / Master of Science / To learn about computer operating systems, students at Virginia Tech implement a command-line shell in their junior-level Computer Systems course. A command-line shell is a computer program that allows the user of a computer to run other programs by typing in the program names. The command-line shell will then run those programs on the user’s behalf. The command-line shell project requires students to understand and use the abstractions that the underlying operating system provides to a computer program. Students often struggle with the project because subtle errors in their implementation can take hours to address. In this work, we developed two analysis tools to pinpoint the root cause of student errors: EshMD and ShellTrace. The EshMD tool models common errors in the command-line shell and checks the student code against those models. Students’ errors are shown by directly pointing to the error locations in their code.
The ShellTrace tool dynamically creates a project specification from a solution written by the course staff and checks that a student solution meets the specification. Generating from the staff solution allows checking the student solution without having to encode the specific project requirements into the tool itself.
We deployed these tools in an undergraduate computer systems class and evaluated our tools based on the number of errors detected and the students’ perceptions of usefulness. We found that the tools detected a significant number of errors and that the majority of students that made use of the tools found them valuable in finding and fixing the errors in their submissions.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/83894 |
| Date | 09 July 2018 |
| Creators | Williamson, Eric Robert |
| Contributors | Computer Science, Back, Godmar V., Butt, Ali R., Lee, Dongyoon |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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