PDOS: Experimenting with Garbage Collection in an Otherwise Conventional OS

操作系统（OS）级别的安全漏洞和崩溃是一个严重的基础设施问题。这些操作系统错误通常是内存管理错误的结果，这是开发人员很难避免的。从长远来看，通过使用高级类型安全语言可以防止大量的内存管理错误，但这些语言是否适合内核实现仍然是一个悬而未决的问题。不幸的是，任何给定的实验来回答这个问题（即，使用特定的高级语言）与传统内核相比，在实现上存在许多差异，这使得很难得出关于高级方法的哪些部分有效以及哪些部分无效的结论。这个项目是一个专门针对遗留操作系统内核的垃圾收集的实验，尽可能少地改变其他实现问题。具体地说，本研究是关于开发工具来自动转换传统内核的C源代码，使其兼容各种精确的垃圾收集策略。该项目的最终目标是检查操作系统是否由于垃圾收集而变得更加可靠，并测量桌面和嵌入式环境中的性能成本。如果实验表明操作系统以合理的成本改进，那么研究将表明如何增加当今计算机系统基础设施的主要部分的可靠性。该项目产生的工具将公开提供，用于研究、应用于实用软件和教学目的。

Security holes and crashes at the operating system (OS) levelrepresent a serious infrastructure problem. These OS bugs are oftenthe result of memory management errors, which are very hard fordevelopers to avoid. In the long run, a broad class ofmemory-management errors can be prevented by using a high-level,type-safe language, but whether these languages are suitable forkernel implementation remains an open question. Unfortunately, anygiven experiment to answer the question (i.e., using a particularhigh-level language) involves many differences in implementationcompared to a conventional kernel, making it difficult to drawconclusions about which parts of the high-level approach work andwhich parts do not. This project is an experiment specifically aboutgarbage collection for legacy OS kernels, changing as few otherimplementation issues as possible. Concretely, the research is aboutdeveloping tools to automatically transform the C source code of aconventional kernel so that it is compatible with a variety of precisegarbage-collection strategies. The project's ultimate goal is to checkwhether the OS becomes usefully more reliable as a result of garbagecollection, and to measure the performance costs in both desktop andembedded environments. If the experiment shows that the OS improves ata reasonable cost, then the research will have shown how to increasethe reliability of a major part of today's computer systemsinfrastructure. Tools generated by the project will be made publiclyavailable for use in research, for application to practical software,and for pedagogical purposes.