Typically, after the handler has run, the temporary data file is erased. One sentence only. Give an analogy. Email is asynchronous and allows us to avoid hard interrupts at the receiving end as well as having to do nothing while we wait for a response at the sending end. Telephones require that we accept hard interrupts to handle the call no matter what we are currently doing, and to wait for someone to answer and respond when we are calling.
Asynchronous processing is much more complex.
It requires that the server take on all the responsibilities of the client, including addressing all of the server binding problems, and requires that the client take on all the responsibilities of the server. Too easy to bother with. Discuss three organizing principles important to remember about Web servers and CGI programming. Include important concepts for the hints given. Make sure your statements are clear, and explain them.