OS X is a user-based operating system where each user that access the system has a separate account that holds preferences and other settings for the user account to run, and also allows the system to implement security by using permissions to restrict filesystem access. While by default you might think of a user account as a human user, many background services like Web servers or database servers, run under special user accounts. These might be called “www,” “http,” or similar, and you can see some of these if you open Activity Monitor. Continue reading →