User-mode Per-process Name Spaces for the AP1000 File System

The perceived simplicity of interprocess cooperation is strongly influenced by the type of name space in which the processes involved execute. If multiple processes share a common name space, they are more likely to cooperate effectively than if each operates in a distinct name space. This paper argues that, especially where specialized resources, such as a supercomputer, are involved, per-process name spaces are the optimum way to provide common name spaces across arbitrary domain boundaries. This paper also argues that such name spaces are best implemented in user mode. The user-mode per-process name spaces supported by the AP1000 File System are then described, as are some of the file system types supported on the AP1000. The performance implications of the user-mode implementation are also examined.