LOCUS a network transparent, high reliability distributed system

Abstract

LOCUS is a distributed operating system that provides a very high degree of network transparency while at the same time supporting high performance and automatic replication of storage. By network transparency we mean that at the system call interface there is no need to mention anything network related. Knowledge of the network and code to interact with foreign sites is below this interface and is thus hidden from both users and programs under normal conditions. LOCUS is application code compatible with Unix2, and performance compares favorably with standard, single system Unix. LOCUS runs on a high bandwidth, low delay local network. It is designed to permit both a significant degree of local autonomy for each site in the network while still providing a network-wide, location independent name structure. Atomic file operations and extensive synchronization are supported. Small, slow sites without local mass store can coexist in the same network with much larger and more powerful machines without larger machines being slowed down through forced interaction with slower ones. Graceful operation during network topology changes is supported.