Chapter 1: Introduction

Section 1.1: Goals and Background

This paper provides an architectural overview of Transarc's wide-area distributed file system, AFS. Specifically, it covers the current level of available software, the third-generation AFS-3 system. This document will explore the technological climate in which AFS was developed, the nature of problem(s) it addresses, and how its design attacks these problems in order to realize the inherent benefits in such a file system. It also examines a set of additional features for AFS, some of which are actively being considered.
This document is a member of a reference suite providing programming specifications as to the operation of and interfaces offered by the various AFS system components. It is intended to serve as a high-level treatment of distributed file systems in general and of AFS in particular. This document should ideally be read before any of the others in the suite, as it provides the organizational and philosophical framework in which they may best be interpreted.

Section 1.2: Document Layout

Chapter 2 provides a discussion of the technological background and developments that created the environment in which AFS and related systems were inspired. Chapter 3 examines the specific set of goals that AFS was designed to meet, given the possibilities created by personal computing and advances in communication technology. Chapter 4 presents the core AFS architecture and how it addresses these goals. Finally, Chapter 5 considers how AFS functionality may be be improved by certain design changes.

Section 1.3: Related Documents

The names of the other documents in the collection, along with brief summaries of their contents, are listed below.
  • AFS-3 Programmer?s Reference: File Server/Cache Manager Interface: This document describes the File Server and Cache Manager agents, which provide the backbone ?le managment services for AFS. The collection of File Servers for a cell supplies centralized ?le storage for that site, and allows clients running the Cache Manager component to access those ?les in a high-performance, secure fashion.
  • AFS-3 Programmer?s Reference:Volume Server/Volume Location Server Interface: This document describes the services through which ?containers? of related user data are located and managed.
  • AFS-3 Programmer?s Reference: Protection Server Interface: This paper describes the server responsible for mapping printable user names to and from their internal AFS identi?ers. The Protection Server also allows users to create, destroy, and manipulate ?groups? of users, which are suitable for placement on Access Control Lists (ACLs).
  • AFS-3 Programmer?s Reference: BOS Server Interface: This paper covers the ?nanny? service which assists in the administrability of the AFS environment.
  • AFS-3 Programmer?s Reference: Speci?cation for the Rx Remote Procedure Call Facility: This document speci?es the design and operation of the remote procedure call and lightweight process packages used by AFS.