Dynamically Configurable Operating Systems

该项目将设计并试验新一代操作系统，该系统支持从构建块块集合构建分布式应用程序。该方法基于以下观察：通信对象是访问分布式环境中的服务和资源的关键。在这样的环境中，用户指定他们想要访问的服务和资源，操作系统动态加载访问这些服务和资源所需的通信对象。系统的核心是对象基础结构。这个基础设施有两个重要的特性。首先，它独立于用户/内核边界。也就是说，组件对象可以驻留在内核中，也可以驻留在一个或多个用户地址空间中，并且可以很容易地在地址空间之间迁移对象。因此，出于保护原因，可以在用户地址空间中构建和测试新对象，然后出于性能原因将其迁移到内核中。其次，内核本身是动态可配置的。也就是说，可以根据活动应用程序的需要在运行时将对象加载到内核中（并从内核中删除）。这个特性意味着内核大小不是一个主要因素——所有可信通信对象在使用时都可以驻留在内核中。在这方面，该建议有两个主要主题：-设计支持动态组合通信服务的操作系统；包括在共享内存多处理器上支持快速通信的实现技术——研究将分布式系统分解为原始构建块的各种方法；并理解控制这些构建块如何组成以提供更高级别服务的原则。

This project will design and experiment with a new generation operating system that supports the construction of distributed applications from a collection of building block pieces. The approach is based on the observation that communication objects are the key to accessing services and resources in a distributed environment. In such an environment, users specify what services and resources they want to access, and the operating system dynamically loads the communication objects necessary to access those services and resources. At the heart of the system is an object infrastructure. This infrastructure has two important features. First, it is independent of the user/kernel boundary. That is, the component objects can reside in either the kernel or in one or more user address spaces, and objects can easily be migrated between address spaces. Thus, new objects can be built and tested in user address spaces for protection reasons, and later migrated into the kernel for performance reasons. Second, the kernel itself is dynamically configurable. That is, objects can be loaded into (and deleted from) the kernel at runtime as required by the active applications. This feature means that kernel size is not a dominant factor--all trusted communication objects can reside in the kernel while they are being used. Within this context, the proposal has two major themes: -Designing operating system support for dynamically composable communication services, including implementation techniques that support fast communication on shared-memory multiprocessors -Investigating various decompositions of distributed systems into primitive building blocks, and understanding the principles that govern how those building blocks are composed to provide higher- level services.