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Examination info for Distributed Systems F2002

  • Dato/Date: June 12th and 17-19th 2002, 9:00-18:00
  • Sted/Place: 12th in room 1.60 and 17-19th in room 1.03.
  • Type: oral
  • Sprog/Language: English or Danish (chosen by the student at the exam)
  • Pensum/Curriculum: here
  • Examinator: Thomas Hildebrandt
  • Censors: Søren Christensen and Jens Bæk Jørgensen
  • Exam plan: here - please check if you are on the list, and if the day is ok
  • Spørgetime/Question hour 10. June 2002, 16:00-17:00, place to be announced

Note: Hver spørgsmål omhandler et relativt bredt emne. Den studerende skal til eksamen gøre rede for dette emne. De underpunkter der er til hvert spørgsmål er kun vejledende og skal ikke opfattes som en komplet disposition for besvarelsen. Den studerende vil bliver vurderet på hvor godt vedkommende demonstrerer kendskab til og overblik over det givne emne.

Tid: Der er ingen forberedelsestid til eksamen. Det forventes at den studerende giver en mundtlig besvarelse af det trukne spørgsmål. Dette bør tage ca. 10 minutter, efterfulgt af ca. 10 minutter til spørgsmål fra eksaminator og censor og 5 minutter til votering.

Hjælpemidler: den studerende må medbringe noter til eksamen, men disse må kun anvendes til at skrive en disposition op på tavlen.

Du er velkommen til at lave 1-2 slides for hvert spørgsmål, så længe de kun indeholder figurer og tabeller (og ikke noter/tekst).

English:

Note: The questions deal with relatively broad topics. The student must at the examination explain esssential aspects of the topic. The subtopics listed for each question are only suggestions and is not a complete overview of the topic. The student will be evaluated on the basis of his/her ability to demonstrate knowledge about and mastering of the topic.

Time: No time is offered for preparation. The student draws a question at random and immediately after starts the presentation of it. The presentation should take 10 minutes, followed by approximately 10 minutes of questioning from the examiners and 5 minutes for evaluation.

Exam aids: The student is allowed to bring notes but they must only be used to write down an outline with keywords at the board.

You are allowed to bring 1-2 slides for each question, but only as long as they contain only figures and tables (not notes or text).

Questions

Question 1 : Implementation of RMI

  • Generic RMI model
  • The role of proxies/stubs, dispatchers etc.
  • Binding of names to their remote references
  • Location of objects from remote references
  • Activation and passivation

Question 2: Name services

  • Role in distributed systems
  • Concepts
  • Name Spaces
  • Name Resolution
  • Java RMI and CORBA Naming Service

Question 3: CORBA

  • architecture
  • the role of adapters and the ORB
  • the role of CORBA IDL
  • CORBA remote references; transient and persistent remote references
  • Activation in CORBA
  • the role of Implementation Repository
  • the Java language mapping - any specialities?

Question 4: Interprocess Communication

  • UDP/TCP, characteristics, failure model
  • External data representation and marshalling, in general, in Java
  • Client-server communication
  • Group communication

Question 5: Java RMI

  • The RMI model
  • Java RMI: goal, implementation, use
  • Semanics: By-reference/by-value
  • Design strategies
  • Safety and Dynamic Class loading
  • Java RMI evaluation

Question 6: Transactions and Concurrency Control

  • Transaction properties
  • The goal of a Concurrency Control protocol
  • Lost update, inconsistent retrival, serial equivalence
  • Aborted transactions and concurrency control
  • Pessimistic versus Optimistic Concurrency Control

Question 7: Lock Based Concurrency Control Protocols

  • The goal for a Concurrency Control Protocol
  • Two-phase locking and strict execution
  • Granularity and use of different locks dependent on types of use
  • Deadlocks (definition, prevention, detection, distributed)

Question 8 : Distributed Transactions and concurrency control

  • flat and nested distributed transactions
  • the role of the coordinator
  • single-phase and two-phase commit protocols
  • recover file
  • recover protocols

Question 9: Replication

  • replication transparancy
  • the role of the front end
  • the relationship between FIFO, causal and total ordering
  • five phases in a request
  • an example of a replicated service

Question 10: Replication - passive and active

  • passive and active replication schemes
  • the use of view-synchronous group communication
  • replication overheads
  • masking of failures

Updated 08/05-2002
hilde@it-c.dk
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