A task is a sequence of actions that a person takes to reach some goal.
Just as we could analyze users into layers we can do the same for tasks.
Physical objects and Evennts: Tools used for the task, material objects that form the starting point and events that occur as the user does the task.
Note that for a computer task the computer and its keyboard are among the physical objects.
Perceptions and Actions: Things a user is aware of during a task, and the actions that the user performs.
Concepts, goals, plans: the users understanding of the objects and the task, the goal to be attained and the mental image of the steps to be taken.
Purpose and Value of the Task: Why are we doing this anyway?