Lecture Notes in Computer Science

Transcription

1 Lecture Notes in Computer Science Edited by G. Goos and J. Hartmanis 105 D.W. Davies E. Holler E.D.Jensen S. R. Kimbleton B. W. Lampson G. LeLann K. J. Thurber R. W. Watson Distributed Systems Architecture and Implementation An Advanced Course FBMathematikTUD Edited by B. W. Lampson, M. Paul, and H. J. Siegert Fachbereich MathematlK Techniscbe Koc.occhu.'e Darmstadt Bib'iothek.nv.-Nr.g 48 SO4 Springer-Verlag Berlin Heidelberg New York 1981

2 Contents 1. Motivations, objectives and characterization of distributed systems 1 Gerard LeLann, INRIA Projet Pilote Sirius 1.1. Motivations Technological changes Microelectronics technology Interconnection and communication technology User needs Objectives Increased performance Extensibility Increased availability Resource sharing Comments Characterization What is distributed? What is new? Distributed system architecture model :...'. 10 Richard W. Watson, University of California Lawrence Livermore Laboratory Introduction Layers and interfaces Abstract objects as a unifying concept The model layers Introduction Need for a distributed operating system Application layer Distributed operating system service layer The interprocess communication layer Hardware/firmware Components Issues common to all layers Introduction Identifiers (naming) Error control ; Resource management Synchronization ; Protection.' Object representation, encoding, translation Testing, debugging, and measurement Global implementation and optimization issues Conclusions 43

3 VI CONTENTS 3. Interprocess communication layer: Introduction 44 Kenneth J. Thurber, Sperry Univac 3.1. Introduction Transmission medium Hardware paths links Intervenors Protocols Protocol properties, : Interconnection structure Multiplexing Arbitration Computer networks versus distributed computers Summary 56 ^4. Hardware interconnection technology 57 Kenneth J. Thurber, Sperry Univac 4.1. Introduction Topologies Point-to-point Multi-point Taxonomies Distributed system interfaces Path allocation Bandwidth/throughput tradeoffs More on protocols Buffers Case studies More on networks versus distributed computers Summary Link level 86 Gerard LeLann, INRIA Projet Pilote Sirius 5.1 Introduction HDLC Frame structure JS HDLC elements of procedure The Arpanet IMP-IMP protocol The Cyclades MV8 protocol Hierarchy 94 Donald W. Davies, Computing Technology Unit, National Physical Laboratory ( ) Richard W. Watson, University of California Lawrence Livermore Laboratory l ( ) 6.1. Introduction The problems of a hierarchy Arpanet as an example Addressing, routing and congestion in large mesh networks 104

4 CONTENTS VU 6.4. Topology optimization Packet versus circuit switching Datagrams and virtual circuits Datagrams Virtual circuits Datagrams vs virtual circuits Network interfaces ' Introduction The pseudo device interface strategy Importance of symmetry Need for error checking at all levels Flow and congestion control Full duplex interface Datagram versus virtual circuit interfaces Xerox PUP as an example datagram interface and service X.25 as an example vc interface Implications of X.25 for distributed systems Network frontends Distributed systems and internetwork design issues Introduction Levels of network interconnection Conclusions J IPC interface and end-to-end protocols 140 Richard W. Watson, University of California Lawrence Livermore Laboratory Introduction IPC service Desired IPC characteristics The IPC interface..< Example IPC service model ' Underlying IPC environment Services required by an EEP of the next lower level Levels of end-to-end services Origin, destination identifiers EEP data objects and data stream synchronization marks Error control and EEP state synchronization Introduction Error types and implications Need for end-to-end error assurance Error control mechanisms used while a connection exists Connection management Comparison of three-way-handshake and timer approaches Bounding maximum-packet-lifetime Reliable control information Protection Resource management Introduction Identifier space Segmentation and reassembly : Flow control Priority.173

5 Vlll CONTENTS Measurement and diagnostics Conclusions Distributed control 175 E. Douglas Jensen, Computer Science Department, Carnegie-Mellon University 8.1. Abstract Introduction The control space Communication and the decentralization of control Acknowledgement Identifiers (naming) in distributed systems 191 Richard W. Watson, University of California Lawrence Livermore Laboratory l 9.1. Introduction Identifier goals and implications 195 ^ 9.3. Unique machine-oriented identifiers Human-oriented names Addresses and routing Conclusion Protection 211 Donald W. Davies, Computing Technology Unit, National Physical Laboratory Basic protection needs Protection in distributed systems Single key cryptography and the Data Encryption Standard Measuring the strength of a cipher system The data encryption standard Block and stream ciphers...; Block chaining : Application of a cipher system at different levels in the hierarchy Key distribution Public key cipher systems The discrete exponential function The power function and its use in cryptography The public key cipher of Rivest, Shamir and Adleman The need for a digital signature The registry of public keys Other public key ciphers and signatures Access control : The access matrix The access control list ; Capabilities Access control lists combined with capabilities A simplified model for changing access rights Capabilities in a distributed system 24Q The location of access control in a distributed system 242

6 CONTENTS IX 11. Atomic transactions 246 Butler W. Lampson, Xerox Palo Alto Research Center Introduction System overview Consistency and transactions The physical system Disk storage Processors and crashes Communication Simple, compound and restartable actions The stable system Stable storage Stable processors Remote procedures Stable sets and compound actions Stable sets Compound atomic actions Transactions Refinements File representation Ordering of actions Aborts Synchronization., 266 Gerard LeLann, INRIA Projet Pilote Sirius Introduction Consistency and atomicity Event ordering and atomicity.: Partial and total orderings Atomic operations Synchronization Synchronization and types of computing systems Fully replicated computing Strictly partitioned computing Partitioned and partially replicated computing Event ordering examples Link protocols Executives Database system nucleus Synchronization mechanisms for distributed systems Centralized versus decentralized synchronization Centralized mechanisms Decentralized mechanisms Evaluation criteria Multiple copy update 284 Elmar Holler, Instiiutfu'r Datenverarbeitung, Kernforschungszentrum Karlsruhe Introduction..; Basic architecture of multiple copy update mechanisms Solutions to the multiple copy update problem 289

7 X CONTENTS Voting solutions Non voting solutions : 300 D.4. Verification of solutions Evaluation of solutions Applications and protocols 308 Stephen R. Kimbleton and Pearl Wang, National Bureau of Standards 3 ( ) Butler W. Lampson, Xerox Palo Alto Research Center ( ) Introduction Supporting program access to data Distributed applications Database management systems (DBMSs) The need for DBMSs DBMS differences Datamodels ; The relational data model The hierarchical data model The Codasyl data model Data manipulation languages Network virtual data managers NVDM desirability and structure Constructing the network-wide view of data Data integrity Controlling access Maintaining meaning Simplifying specification XNDM - An Experimental Network Data Manager Translation technology Nature of the translation function Translation alternatives : The query translation process an informal description A taxonomy of major translation issues : Implementation approach XNQL translator specifics Data transfer protocols (DTPs) DTP services Data and its translation/transformation Implementing a data translator/transformer A data transfer protocol An example-the NBS experimental network operating system XNOS overview Supporting uniform system-system interactions Parameter and data representation Types Binding Encoding : Conversion : Debugging, testing and measurement A remote debugger Monitoring communication Eventlogs ; Remote procedure calls : 365

8 CONTENTS Xi The no-crash case The crash case Error recovery 371 Gerard LeLann, INRIA Projet Pilote Sinus Introduction Basic concepts and definitions Error recovery The Tandem/16 computing system Sirius-Delta ' Transaction commitment Recovering from failures Unrecoverable faults and failures Hardware issues 377 Kenneth J. Thurber, Sperry Univac 4 ' => Introduction Design issues Executive control functions Approach ' Hardware concept Implicit primitives Explicit primitives Functionally Distributed Architectures (FDA) Control overhead Virtual Machines (VM) and Virtual Machine Monitors (VMM) Local networks." Introduction : Application embedded hardware Tum key systems i Subsystem building blocks Components/modules Chips : Hardware overview Network Systems Corporation HYPERchannel Further issues Conclusion Hardware/software relationships in distributed systems 413 E. Douglas Jensen, Computer Science Department, Carnegie-Mellon University Introduction Assigning functionality to layers i The implementation of functions within layers Hardware/software relationships in distributed computer systems Bus bandwidth Bus medium Broadcasts Acknowledgment deferral Transmission addressing Communication support.419

9 xii CONTENTS Bit/word/transmission synchronization Conclusion The National Software Works (NSW) 421 ElmarHoller, InstitutfurDatenverarbeitung, Kernforschungszentrum Karlsruhe Introduction, System architecture NSW components MSG: The NSW interprocess communication facility Front end: The NSW user interface Foreman: providing the tool execution environment File Package: Thefile handling facility for NSW Works Manager: The NSW monitor The NSW reliability concept DAD: A debugging tool for debugging NSW Ethernet, Pup and Violet 446 Butler W. Lampson, Xerox Palo Alto Research Center The Alto and the Ethernet Implementation The Pup internetwork Introduction Design principles and issues The basic model: networks connected with gateways Simplicity Datagrams versus virtual circuits.' Individual networks as packet transport mechanisms Internetwork gateways ' A layered hierarchy of protocols : ; Naming, addressing, and routing Flow control and congestion control Reliable transport Packet fragmentation Implementation Level 0: Packet transport Level 1: Internetwork datagrams Level 2: Interprocess communication Level 3: Application protocols The distributed file system : Introduction Access mechanics Client responsibilities Server crashes and aborted transactions Local caches of shared data : Directories Summary ' Violet: A distributed, replicated calendar system...: Introduction Environment ' System architecture ~.! Replicated data : Sharing and locking The performance of the architecture 482

10 CONTENTS XU Implementation notes Conclusion Conclusion 486 Kenneth J. Thurber, Sperry Univac Introduction What we have defined What we think we know What we conjecture What we think we don't know What we advise What you should know What we don't agree upon Acknowledgements 492 References 493 Index 507