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。这些操作系统错误往往是内存管理错误的结果，开发人员很难避免这些错误。从长远来看，一大类内存管理错误可以通过使用高级、类型安全的语言来防止，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，任何回答这个问题的实验(即使用特定的高级语言)都涉及到与传统内核相比在实现方面的许多差异，这使得很难得出结论，即高级方法的哪些部分有效，哪些部分无效。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，研究的是开发工具，自动转换一个传统的内核的C源代码，使其与各种精确的大容量收集策略兼容。该项目的最终目标是检查垃圾收集是否使操作系统变得更加可靠，并衡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提高了一个合理的成本，那么这项研究将表明如何提高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之于众，可用于研究、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.