Final answer:
A crash at the checkpoint during writing to a file system causes no impact on data integrity due to the journaling process, which ensures data is committed to the memory and disk. The file system will use log files to roll back incomplete writes and maintain consistency, without needing to restore the checkpoint itself.
Step-by-step explanation:
When a crash happens at the checkpoint during writing to a file system (FS), the answer is b) No impact on data integrity. Checkpoints are a part of a database and file systems logging or journaling process, which ensure that, even in the event of a system crash, the data integrity is maintained. The purpose of a checkpoint is to write all outstanding changes in the system's buffer cache to disk, which includes the data files and the journal or log files that record the changes to the file system. If the system crashes, the data written up to the last checkpoint is safe, as it has been committed to the memory and disk.
After a crash, during the recovery process, the file system will refer to these journal or log entries to restore the system to the last consistent state. This means that any writes that were not completed will be rolled back using the information stored in the log files, ensuring the consistency of the file system without data loss or corruption. Therefore, while some recent writes may be lost, the integrity of the data up to the last successful checkpoint remains intact. The file system does not necessarily restore the checkpoint itself; rather, it continues with the normal operation after ensuring the integrity of the data.