INTRODUCTION

In 1968 the University of California Berkeley Campus Computer Center began a project to design and implement a Time Sharing System for a Control Data Corporation (CDC) 6400 computer, with Extended Core Store (ECS). The project continued until the Fall of 1971 when it was terminated due to a lack of funds. The author was a member of the project from the beginning, and was director at its termination. The system we designed, CAL TSS, included a number of ideas proposed by other projects, that had not yet been fully tested. These included the concept of capability based protection (system maintained pointers to system objects, through which all access to those system objects must pass), and a mapped address space (all storage resides in files, and all load and store machine instructions actually access data in some file, rather than in a local memory). In contrast to other projects, such as Multics [C3], this was a small project. At its peak, there were about eleven people involved, many part time. This thesis contains a discussion of some of our underlying ideas, describes the system we constructed and finally some reactions to that system. Part One describes the project, the hardware and the underlying ideas. Part Two describes the system. Finally, Part Three contains my reactions to various aspects of the system.