this paper we discuss the design and implementation of the/'fiesystem interface in the kernel and the NF$ virtual/'fiesystem. We describe some interesting design issues and how they were resolved, and point out some of the shortcomings of the current implementation. We conclude with some ideas for future enhancements

Digital Equipment Corporation The 1980s have witnessed the emergence of a new architecture for computing based on networks of personal computer workstations. The performance requirements of such systems of workstations places a strain on traditional approaches to network architecture. The integration of diverse systems into this environment introduces functional compatibility issues that are not present in homogeneous networks. Effective prescriptions for functional compatibility, therefore, must go beyond the com-munication paradigms used in present distributed systems, such as remote procedure calls. This paper proposes a distributed system architecture in which communication follows a program-ming paradigm. In this architecture a programming language provides remote service interfaces for the heterogeneous distributed system environment. This language is a flexible and efficient medium for implementing service function protocols. In essence, clients and servers communicate by program-ming one another.

The Sun Network Filesystem (NFS™) provides transparent, remote access to filesystems. Unlike many other remote filesystem implementations under UNIX®, NFS is designed to be easily portable to other operating systems and machine architectures. It uses an External Data Representation (XDR) specification to describe protocols in a machine and system independent way. NFS is implemented on top

Current approaches for checkpointing and recovery assume system homogeneity, where checkpointing and recovery are both performed on the same processor architecture and operating system configuration. Sometimes it is desirable or necessary to recover the failed computation on a different processor architecture, with possibly different byte-ordering and data-alignment specifications. This implies that checkpointing and recovery must be portable. We provide portability by means of a universal checkpoint format that allows object codes to resume execution from a checkpointed state, allowing for fast execution of already compiled code, rather than interpreting or compiling on the fly. This paper describes the system support needed to implement portable checkpoints, and the shadow checkpoint algorithm to checkpoint and recover a sequential process. Experimental results on three different architecture-operating system combinations demonstrate the checkpointing overhead and the cost of recov...

This paper gives a survey of all common transparent distributed systems. We distinguish between Distributed File Systems (DFS) and Distributed Operating Systems (DOS). Our overview is focussed on systems providing at least access or location transparency. The paper is organized as follows: The introduction offers definitions of the features of each transparent distributed system as well as the services it is able to provide. We also propose a catalog of criteria that enables us to compare different systems independently of implementation done. The main entries we make are heterogeneity of the system's environment, communication strategy, as well as naming and security issues. Finally, we examine the reliability and availability of the separate systems and the way these issues are achieved. The following section consists of the survey. The description of each system is organized as follows: First, we introduce the main goal the system was developed for, the classification of th...

Abstract. In its simplest form, checkpointing is the act of saving a program’s computation state in a form external to the running program, e.g. the computation state is saved to a filesystem. The checkpoint files can then be used to resume computation upon failure of the original process(s), hopefully with minimal loss of computing work. A checkpoint can be taken using a variety of techniques in every level of the system, from utilizing special hardware/architectural checkpointing features through modification of the user’s source code. This survey will discuss the various techniques used in application-level checkpointing, with special attention being paid to techniques for checkpointing parallel and distributed applications. 1