Briefly answer the following questions:

1. How is checkpointing done in ARIES?

2. Checkpointing can also be done as follows: Quiesce the system so that only checkpointing activity can be in progress, write out copies of all dirty pages, and include the dirty page table and transaction table in the checkpoint record. What are the pros and cons of this approach versus the checkpointing approach of ARIES?

3. What happens if a second begin checkpoint record is encountered during the Analysis phase?

4. Can a second end checkpoint record be encountered during the Analysis phase?

5. Why is the use of CLRs important for the use of undo actions that are not the physical inverse of the original update?

6. Give an example that illustrates how the paradigm of repeating history and the use of CLRs allow ARIES to support locks of finer granularity than a page.