Beyond UNIX---A True Distributed System for the 1990s

Lecture Notes in Computer Science, 1990

Centre for Mathematics and Computer Science Amsterdam AMOEBA is a research project to build a true distributed operating system using the object model. Under the COST11-ter MANDIS project this work was extended to cover wide-area networks. Besides describing the system, this paper discusses the successive versions in the implementation of its model, and why the changes were made. Its purpose is to prevent ourselves and others from making the same mistakes again, and to illustrate how a distributed operating system grows in sophistication and size. I. Why This Paper "Those who learn nothing fi'om history are doomed to repeat it"-Santayana For about eight years now, we have been doing research on distributed operating systems, not only behind our desks, but also behind our terminals. The distributed system we are developing is called AMOEBA[l], and it is constantly evolving. It is being developed at the Vrije Universiteit and the Centre for Mathematics and Computer Science (CWI), both in Amsterdam. AMOEBA currently runs on Motorola 68020, National Semiconductor 32032, and MicroVax II processors. Both Ethemet and the Pronet token ring are supported by AMOEBA, and can be connected by a bridge. COST11-ter MANDIS is an international project investigating the management requirements for large international networks of computers. It has adopted the object-model as a framework within which to discuss the management of wide-area distributed systems. To experiment with this, the MANDIS project adopted the Amoeba distributed operating system, extended with a gateway for wide-area communication. Amoeba systems in Holland (Vrije Universiteit, CWI), the U.K. (Harwell Laboratories, Haffield Polytechnic), in Berlin (GMD/FOKUS) and in Norway (University of Troms0) have been connected into a single, transparent distributed system.

ACM Computing Surveys, 1985

Distributed operating systems have many aspects in common with centralized ones, but they also differ in certain ways. This paper is intended as an introduction to distributed operating systems, and especially to current university research about them. After a discussion of what constitutes a distributed operating system and how it is distinguished from a computer network, various key design issues are discussed. Then several examples of current research projects are examined in some detail, namely, the Cambridge Distributed Computing System, Amoeba, V, and Eden.

Unlike many other operating systems, Amoeba is a distributed operating system that provides group communication (i.e., one-to-many communication). We will discuss design issues for group communication, Amoeba's group system calls, and the protocols to implement group communication. To demonstrate that group communication is a useful abstraction, we will describe a design and implementation of a fault-tolerant directory service. We discuss two versions of the directory service: one with Non-Volatile RAM (NVRAM) and one without NVRAM. We will give performance figures for both implementations.

1991

This paper compares two distributed operating systems, Amoeba and Sprite. Although the systems share many goals, they diverged on two philosophical grounds: whether to emphasize a distributed computing model or traditional UNIX-style applications, and whether to use a workstation-centered model of computation or a combination of terminals and a shared processor pool. Many of the most prominent features of the systems (both positive and negative) follow from the philosophical differences. For example, Amoeba provides a high-performance user-level IPC mechanism, while Sprite's RPC mechanism is only available for kernel use; Sprite's file access performance benefits from client-level caching, while Amoeba This work was supported in part by the Netherlands Organization for Scientific Research (N.W.O.) under grant NF 62-334.

Proceedings of the ninth ACM symposium on Operating systems principles - SOSP '83, 1983

Is a distributed operating system which supports transparent access to data through a network wide fllesystem, permits automatic replication of storaget supports transparent distributed process execution, supplies a number of high reliability functions such as nested transactions, and is upward compatible with Unix. Partitioned operation of subnetl and their dynamic merge is also supported. The system has been operational for about two years at UCLA and extensive experience In its use has been obtained. The complete system architecture is outlined in this paper, and that experience is summarized.

1979

Roscoe is an operating system implemented at the University of Wisconsin that allows a network of microcomputers to cooperate to provide a general-purpose computing facility. After presenting an overview of the structure of Roscoe, this paper reports on experience with Roscoe and presents several problems currently being investigated by the Roscoe project.

Microprocessing and Microprogramming, 1988

A new generation of operating system was born during the last ten years: a distributed operating system oriented network. Three key-concepts are strongly developed: standardization, distribution and parallelism. One of these systems is CHORUS TM. This project launched at INRIA has elaborated an architecture for distributed systems. CHORUS is now being commercialized by the CHORUS systems company; it will be ported in the next few years on different machines, starting with the sPs7, PC/AT and SUN. CHORUS offers UNIX TM compatibility, is independent of the hardware architecture and of the network.

Computer, 1991

udging from the enormous amount of distributed-system research carried out over the past decade, information processing experts have come t o recognize the advantages these systems possess. These research activ-J ities have led to the availability of more than 50 network and distributed systems. However, most of these systems can only partially succeed in attaining the major goals of a distributed system, which include transparency, higher performance, higher reliability and availability, and higher scalability. Of course, attaining all these goals in the first attempt is impossible. Nonetheless, gradual improvements are possible by learning from existing systems and trying to overcome their limitations. The University of Tokyo's Galaxy research project attempts to design, implement, and use a distributed computing environment based on this idea. Design goals and novel aspects Analyzing why existing In designing Galaxy, our primary goal was to build a distributed operating system suitable for use in both local and widearea network workstations. T o achieve this goal, we eliminated the use of broadcast protocols in any of our mechanisms, avoided the use of global-locking o r time-stamp-ordering mechanisms while maintaining the consistency of replicated information, and decentral-distributed systems are limited, the Galaxy research project borrows many concepts and proposed facilities ized the management of all globally useful information. novel system features that helped us achieve this goal include O u r second major goal was to ensure high performance. Design decisions and and integrates them developing the Galaxy kernel from scratch, rather than modifying a n existing using multiple-level interprocess communication mechanisms to meet the with its own novel Unix kernel; design features.

1970

The goal of this project Is to plan and develop a computing system that will provide interactive computing services with a high degree of reliability, a variety of language systems, incremental expansion capability, competitive costs, a respect for human factors considerations; and the project will require only a modest amount of system programming r e s o u r c e s .

The current direction of computer systems is increasingly moving away from centralised system and moving towards distributed sets of workstations and personal computers connected by a network, known as distributed systems. This has led to the development of specialised operating systems to take full advantage of the resource sharing potential that a distributed system provides. The specialised operating systems being developed for these situations are known as Distributed Operating Systems. Research into this area is still at the primary stage with little firm evidence indicating what components of Distributed Operating systems are more important than others.