NAMING OF FILES IN DISTRIBUTED SYSTEMS (TILDE, REMOTE, UNIX, NETWORK)
Abstract
Naming is among the most important characteristics of a com- puter system. The research discussed in this dissertation investi- gates issues in the naming of files in distributed systems. Distributed naming mechanisms are difficult to construct for many reasons. For example, disjoint computing environments in a distributed system may make access to remote files difficult. A distributed naming mechanism must be able to function despite the loss of some com- ponents of the distributed system. Distributed computing systems may include replicated or redundant files, which the naming mechanism must be able to distinguish and identify. We have developed the Tilde naming system, which addresses the specific problems identified in our study of distributed naming. The Tilde naming system breaks the name evaluation procedure into two components: a per-process local naming environment and a global, transparent access mechanism. In place of a global or hardware-dependent naming structure, the Tilde naming system organizes network files into collections of related files known as Tilde Trees. Files within Tilde Trees are organized, as the name implies, into a tree, providing the familiar advantages of hierarchical naming within the components of a given subsystem. Each user can then organize Tilde Trees into a Tilde Forest, a local naming environment specific to the user's naming requirements. Tilde trees are identified by a universal, network-wide access mechanism, independent of any particular network component. To investigate Tilde naming in a real-world environment, we have implemented the Tilde naming mechanism in an experimental computing network. The Tilde naming mechanism is implemented in a modified version of the UNIX('(DAG)) operating system kernel running on a network of VAX('(DBLDAG)) computers. Additional modifications to existing application programs and the construction of new software provide a complete experimental facility for exploring the Tilde naming sys- tem. Questions raised by the experimental system have provided direction for our research and experience with the implementation has justified our decisions and basic design. This thesis, then, maintains that contemporary hierarchical naming systems are inappropriate for distributed systems, providing neither the flexibility required by the individual user, nor the universal access required for reliable network access. We present the Tilde naming mechanism as an alternative to global naming hierarchies for distributed naming. ('(DAG))UNIX is a Trademark of Bell Laboratories. ('(DBLDAG))VAX is a trademark of Digital Equipment Corporation.
Degree
Ph.D.
Subject Area
Computer science
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