DITRIBUTED SYSTEMS

MCA II Year, II Semester

Osmania University

UNIT I

1. i. Draw the general organization of an internet search engine into three layers and exlain the three layers.

ii. Distinguish between multiprocessing and multi programming. (Feb 12)

2. i. Explan the software agents in distributed system.

ii. Why is it often necessary to specify the ontology in an ACL language. (Feb 12)

3. i. List various properties of adaptive software agents.Where do Agent communication Languages(ACLs)

fit into the OSI model?Why is it often necessary to specify the ontology in an ACL message? (Feb 12)

4. i. Explan the need of code migration.

ii. Discuss about client/server model. (Feb 12)

5. i. Discuss the golas of Distributed System.

ii. Explan about client-server model. (July 11)

6. i. Explain about software agents.

ii. Give the importance of code migration in distributed system. (July 11)

7. i. What are the properties of adaptive software agents? Where do Agent Coomunication Language(ACLS)

fit into the OSI model? Why is it often necessaty to specify the ontology in the ACL message?

ii. Explain how micro kernels can be used to organize an operating system in a client server fashion.

(July 10)

8. i Explain client-server architectures.

ii Explain network operating system. (Nov 09)

9. Explain about server

(i) General design issues (ii) Object servers (Nov 09)

10. i What is the difference between a distributed operating system and a network operating system.

ii Consider a chain of process P1,P2 ...... Pn implementing a multitiered client server architecture. Process Pi

is client of process Pi+1 and Pi will return a reply to Pi+1 only after receiving a reply from Pi+1. What are the

main problems with thias organization when taking a look at the reply-request performance at proccess Pi?

iii What are the properties of adaptive software agents? Where do Agent Communication Languages (ACLs)

fit into the OSI model? Why is it often necessary to specify the ontology in an ACL message?( May 09)

11. i Explain how microkernels can be used to organize an operating system in a client server fashion.

ii An experimental file server is up 3/4 of the time and down 1/4 of the time, due to bugs.How many times

does this file server have to be replicated to give an availaility of at least 99 per cent?

iii Compare the architecture of ‘D’ Agents with that of an platform in the FIPA model. ( May 09)

12. i Explain hardware concepts of distributed systems. (Nov 08)

ii Explain about uniprocessor operating systems.

13. Explain: (Nov 08)

i Introduction to threads.

ii Threads in distributed systems.

14. i Explain the role of middleware in a distributed system (May 08)

ii What is the difference between vertical distribution and horizontal distribution?

iii Sketch the design of a multi threaded server that supports multiple protocols using sokets as its transport

levelinterface to the underlying operating system.

15. i Explain what is meant by transparency and give examples of different types of transparancy. (May 08)

ii What is an open distributed system and what benafit does open ness provide?

iii Discuss various approaches to code migration. Also mention the alternatives for code migration.

16. i Discuss the advantages of distributed systems over centralized ones.

ii Explain the client server communication in a distributed system. (May/June 07)

17. Briefly explain the following:

i Scalability in ditributed systems

ii Blocking vs.Non Blocking primitives

iii Threads

iv. Virtual memory. (May/June 07)

UNIT –II

1. Explan in detail about home-based and hierarchical approaches in mobile agents. (Feb 12)

2 How can the limitation of Lamport’s logical clocks be over comes?What is a “Strongly consistent global

state”? (Feb 12)

3. What is mean by naming?Explain about implementation and working of DNS. (Feb 12)

4. i. Differentiate between logical clock and global clock.

ii. Describe mutual exclusion. (Feb 12)

5. i. Write about X.500 and its importance.

ii. Explain how mobile entities are located. (July 11)

6. Discuss about election algorithms by taking suitable examples. (July 11)

7. i. Expalin the concept of removing unreferenced entites.

ii. What is the idea behind optimistic concurrency control ? What are its advantages ? Is optimistic

concurrency control more or less restrictive than using times stamps ? Discuss. (July 10)

8. Explain naming entites (Nov 09)

i Names,Identifiers ad addresses.

ii Name resolution.

9. Explain the concept of clock synchronization. (Nov 09)

10. i Show that weighted reference counting is more efficient than simple reference counting. Assume that

communication is reliable.

ii It is possible in generation reference counting that an entry G[i] become less than 0 ?

iii What is the idea behind optimistic concurrency control? What are its advantages ? Is optimistic concurrency

control more or less restrictive than using times stamps ? Discuss. (May 09)

11. i A special form of locating an entity is called casting, by which a service is identified by means of an IP

address. Sending a request to an any cast address returns a response from a server implementing the

service identified by that any cast address. Outline the implementation of any cast service based on the

hierarchial location service.

ii Give a comparison of three mutual exclusion algorithms that you have studied. (May 09)

12. Explain the concept of locating mobile entities. (Nov 08)

13. Explain the concept of logical clocks. (Nov 08)

14. i What are the basic approaches for locating mobile entities? (May 08)

ii What is the goal of an election algorithm? Explain election algorithm based on the use of a ring.

15. i Compare garbage collection that requires the support of reference counting with that of trace based

methods.

ii Explain any one algorithm for achieving distributed mutual exclusion. (May 08)

16. i Explain the role of each layer in centralised file system modules.

ii Explain the difference between stateful and stateless file server. (May/June 07)

17. Explain in brief the design and implementation of DNS and X.500. (May/June 07)

UNIT – III

1. Write the different types of consistency protocals explain in details. (Feb 12)

2. Using the finite state automata, explain the non-blocking commit protocols is useful in fault toleranace.

(Feb 12)

3. i. Discuss briefly about client-centric consistency model.

ii. Write about process resilience. (Feb 12)

4. i. Explain about distributed commit and recovery.

ii. Explain about data centric model. (Feb 12)

5. Explan about Distribution and Consistency models briefly. (July 11)

6. i. Discuss about process resilience.

ii. Explain about Data centric model. (July 11)

7. i. Explain about distribution and consistency protocols.

ii. Explain the concept of distributed commit and recovery. (July 10)

8. Explain the concept of consistency protocols. (Nov 09)

9. Explain the concept of reliable group communication. (Nov 09)

10. i How do you compare push - based and pull - based protocols in the case of multiple client, single server

systems.

ii Explain replica placement issues.

iii In three phase commit protocol, it appears that commiting a transaction is based on majority voting. Is this

true. (May 09)

11. i Caching protocols form a special case of consistency protocols-Discuss.

ii Characterize the message - logging schemes. (May 09)

12. Explain about distribution protocols. (Nov 08)

13. Explain about process resilience? (Nov 08)

14. i Why is replication useful? How does replication relate to scalability? (May 08)

ii Can linearizability be implemented for physically distributed data stores?

iii For each of the following applications, do you think at-least-once semantics or at most ance semantic is

best? Discuss.

(a) Reading and writing files from a file server.

(b) Compiling a program.

(c) Remote Banking.

iv. In two-phase commit protocol, why can blocking never be completely eliminated, even when the participants

elect a new coordinator?

15. i Explain the different consistency models for distributed shared memory. (May 08)

ii Briefly explain the motion of incremental snapshot.

16. Discribe the design and implementation issues of distributed mutual exclusion. (May/June 07)

17. Describe with example, the basic architecture model of replication in a distributed data base(May/June 07)

UNIT – IV

1. Give an overview of GLOBE and explain how binding a process to an object is done in GLOBE.

(Feb 12)

2. Write a comparsion between CORBA,DCOM and GLOBE. (Feb 12)

3. i. Discuss about CORBA architecture and the role of ORB in CORBA.

ii. Describe the working of GLOBE. (Feb 12)

4. i. Explain about distributed file system.

ii. Discuss the implementation of CODA file system. (Feb 12)

5. Write short notes on the following: (i) CORBA (ii) GLOBE (July 11)

6. Explan briefly about SUN NFS and CODA file systems. (July 11)

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MCA II Year,II Semester

7. i. Write short notes on (i) CORBA and (ii) DCOM.

ii. Mention the design goal of Globe. Give an overview of Globe. (July 10)

8. Compare NFS and Coda distributed file systems on major design issues. (July 10)

9. Explain the details of globe. (Nov 09)

10. Explain the details of SUN NFS. (Nov 09)

11. i Write shot notes on type library and monikers in DCOM.

ii Describe the architecture of NFS distributed file system. (May 09)

12. i Mention the design goal of Globe. Give an overview of globe.

ii Compare NFS and Coda distributed file systems on major desgin issues. (May 09)

13 . Explain the following concepts of CORBA. (Nov 08)

(a) Communication

(b) Process

(c) Security

14. Explain about coda file system. (Nov 08)

15. i What is the design goal of CORBA? Give an overview of CORBA system. (May 08)

ii In NFS, attributes are cached using write-through cache coherence policy. is it necessary to forward all

attributes changes immediately?

16. i Compare DCOM and Globe. (May 08)

ii In NFS, what kind of security measures can be taken to prevent a malicious client from reclaiming a lock it

never was granted when a server enters its grace period?

iii Explain how coda solves read-write conflicts on a file that is shared between multiple readers and only a

single write.

17. i Discuss log based transaction recovery.

ii Explain private workspaces as a method for implementing transactions. (May/June 07)

18. Compare and contrast the various methods used for concurrency control. (May/June 07).

UNIT - V

1. Write short notes on:

i. Design issues in distributed shared memory.

ii. Memory coherence. (Feb 12)

2. Write the different types of algorithms for implementing distributed shared memory.Give one explample

(Feb 12)

3. Explain how shared memory implemented by taking any one implementation algorithm. (Feb 12)

4. Explain briefly about load distributing algorithms by taking suitable examples. (Feb 12)

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MCA II Year,II Semester

5. What is meant by memory coherence protocol?Explain about design issues of shared memory and list

implementation algorithms. (July 11)

6. i. What are issues in load distributing? Explain.

ii. Explain briefly about load distributing algorithms. (July 11)

7. i. Explain about (i) Coherence protocols. (ii) Design issues. (July 10)

8. i. Explain about (i) Issues in load distributing. (ii) Load distribution algorithms. (July 10)

9. i Explain algorithms for implementing DSM.

ii Explain about memory consistence. (Nov 09)

10. Explain about lead distributing algorithms. (Nov 09)

11. i What do you mean by memory access orderings ?

ii Differentiate between load balancing verses load sharing.

iii Explain receiver initiated load sharing algorithm. (May 09)

12. i Explain the alogorithm for implementing distributed shared memory.

ii Distinguish between pre-emptive verses non pre-emptive transfers of tasks in local

distribution algorithms. (May 09)

13. Explain about load distribution algorithms. (Nov 08)

14. i Explain the algorithms for implementing DSM.

ii Explain about design issues of distributed shared memory. (Nov 08)

15. i Explain why write-invalidate protocol is suitable to maintain coherence if several updates occur between

reads or when a program exhibits per-node locality of reference.

ii Classify the load distribution algorithms.

iii Explain the sender initiated algoriyhm for load distribution. (May 08)

16. i Contribute your comments on granularity and page replacement issues in the design of distributed shared

memory systems.

ii Explain briefly about adaptive algorithm for load distribution. (May 08)

17. i What are the goals of transaction management in a distributed system?

ii What are the communiction failures in a distributed system? Explain the different ways to recovery of

distributed transacions. (May/June 07)

18. i Briefly discuss the components and functions of kerberos.

ii Briefly discuss the X.590 certificates. (May/June 07