Emerald

Developed by:
University of Washington, USA Norman C, Hutchinson, Rajendra K. Raj, Andrew P. Black, Henry M. Levy, Eric Jul, E.D. Lazowska, and G.T. Almes

Short Description:
Emerald is a distributed object-based language and system, designed to simplify the construction of distributed programs. An explicit goal of Emerald is object mobility; objects in Emerald can freely move within the system to take advantage of distributio n and dynamically changing environments. Its main innovation to Eden is that it presents a unified view of objects regardless of their size. This is called fine-grained mobility, because Emerald objects can be small data objects as well as objects with pr ocesses. Thus the unit of mobility can be much smaller than in process migration systems which typically move entire address spaces. Object mobility in Emerald subsumes both process migration and data transfer.

Model: loosely coupled, integrated
Properties: object-oriented, process migration
Transparency: access, location, migration
Running on: MicoVAX II, Sun-3
Date: 1986Ð1987

References:
Norman C. Hutchinson: "Emerald: An ObjectÐBased Language for Distributed Programming". Department of Computer Science, University of Washington, Seattle, WA (USA), January 1987.
Rajendra K. Raj, Ewan Tempero, Henry M. Levy, Norman C. Hutchinson and Andrew P. Black: "The Emerald Approach to Programming". Department of Computer Science, University of Washington, Seattle, WA (USA), November 1988.

E. Jul, H. Levy, N. Hutchinson and A. Black: "Fine-grained mobility in the Emerald system". Proc. of the Eleventh ACM Symposium on Operating System Principles, November 1987, pp. 105-106.