Abstracf-Since 1984, the goal of the Bubba project at MCC has been to design a scalable, high-performance and highly available database system that will provide significant costlperformance advantages over conventional mainframes in the 1990's. The design process has been an iterative one, cycling through design, modeling, and prototyping in progressive detail. The current Bubba prototype runs on a commercial 40-node multicomputer and includes a parallelizing compiler, distributed transaction management, object management, and a customized version of UNIX. This paper describes the current prototype and discusses of the major design decisions that went into its construction. The lessons learned from this prototype and its predecessors are presented.Index Terms-Complex object management, database operating system, database programming language, database system performance, database system prototype, dataflow execution, parallel database system.