フリー問題

問題文

Which statement correctly describes how the local backend handles concurrent operations on the same working directory?

選択肢

1. It creates a lock file next to the state file, which must be deleted by hand after any command that was interrupted, since the operating system cannot release a lock held by a process that has already exited.
2. It locks the state using operating system facilities, so a second command on the same machine waits or fails rather than writing at the same time.
3. It serializes operations on the local state file by queueing them, so a second command starts automatically as soon as the first one fully finishes.
4. It does not lock at all, since locking is a feature of remote backends only.