Chapter 7

Question 1

Consistency model

Answer 1

A contract between a DS ( data-store ) and its process

Question 2

Strict consistency

Answer 2

Absolute time ordering of all shared accesses matters

Question 3

Sequential consistency

Answer 3

All processes see all shared accesses in the same order . Accesses are note ordered in time.

Question 4

Casual consistency

Answer 4

All processes see casually related shared accesses in the same order.

Question 5

Week consistency

Answer 5

Shared data can be counted on to be consistency only after synchronisation is done .

Question 6

Release consistency

Answer 6

Shared data are made consistent when a critical region is existed.

Question 7

Entry consistency

Answer 7

Shared data pertaining to a critical region are made consistent when a critical region are entered.

Question 8

Eventual consistency

Answer 8

When no update occur for a long period of time, eventually all updates will propagate through the system and all replicas will be consistent

Question 9

Replicas types

Answer 9

1. Permanent replica.
2. Server intended replicas.
3. Client intended replicas.