DS notes #3

Dt 19-1-17
(5 marks question)

• Issues in designing distributed system

1. Transparency
2. Flexibility
3. Reliability
4. Performance
5. Scalability
6. Fault tolerance

1. Transparency

• Hide from the users - processes and resources - distributed across network.

• Types of transparency

1. Access transparency
2. Location transparency
3. Migration transparency
4. Relocation transparency
5. Replication transparency
6. Concurrency transparency
7. Failure transparency
8. Persistence transparency

1) Access transparency

-hides differences in data representation and how resources accessed.

2) Location transparency

• Hides where a resources is physically located.
• Archived -assign - logical names resources.

3) Migration transparency

• Hides movements of resources to another location.
• Resources - change location without changing names.

4) Relocation transparency

• Hides movement of resources to another location - while in use.

5) Replication transparency

• Hides multiple copies of resource exists.

6) Concurrency transparency

• Hides - resource may be shared by several users.

7) Failure transparency

• Hide - failure and recovery - resource and persistence - hide - resources - in memory on disks