Development of an operating system that supports the distributed and persistent light-weight objects

我们设计并实现了一个支持轻量级对象的操作系统。在这一年里，我们开发了分布式处理工具，如远程对象调用、全局命名和对象复制/迁移等。我们设计了与位置无关的远程对象调用，这是分布式处理的基础。我们使用代理技术将本地对象调用转换为消息传递。我们的代理提供了全局命名、结果缓存和访问控制等功能。我们为复制对象设计了用户定义的一致性控制。一致性控制在方法调用级别执行。开发了资源管理设施。它们被用作用户级对象复制和迁移等的基础。我们定义了使用这些工具的接口，并使用该接口实现了一些简单的负载平衡策略。设计了将远程对象映射到虚拟地址空间的机制。第一次调用对象时，将对象映射到地址空间，并由操作系统内核执行访问检查。但是，随后的对象调用完全在用户级别执行。实现是通过修改NetBSD来实现的，NetBSD是一个自由软件操作系统。

We designed and implemented an operating system that supports light-weight objects. In this year, we developed the destributed processing facilities such as remote object invocation, global naming, and object replication/migration, etc.1. We designed location-independent remote object invocation, which is a basis for distributed processing. We used the proxy technique for translating local object invocation to message passing. Our proxy provides the facilities of global naming, results caching and access control.2. We designed the user-defined consistency control for replicated objects. The consistency control is performed at the method invocation level.3. The resource management facilities were developed. They are intended to use as the basis ofuser-level object replication and migration, etc. We defined the interface for using the facilities, and implemented some simple load balancing policies using this interface.4. We designed the mechanism of mapping remote objects to a virtual addres space. When an object is first invoked, the object is mapped to an address space and the access check is performed by the operating system kernel. However, the subsequent object invocations are performed completely at the user level.5. The implemention was performed by modifying NetBSD,which is one of the free software operating systems.