1. The process abstraction is a popular way to organize concurrent programs, but it is not the only choice. An alternative to the process abstraction is to design a single-threaded program that maintains queues of work to do: that program never blocks as long as there is work to do, but completes each work item it starts (natural break), then switches to working on another pending work item. In particular, the application does not block awaiting input but instead polls to find if input is available: processing requests are typically divided into several work items, that may be immediately queued as work to be done, or may be delayed pending completion of other work requests. Discuss this alternative vis-à-vis implementing the program as several processes coordinated by a general-purpose operating system.