1. A task management system for executing a task selected from a plurality of tasks, the system stored on a computer-readable medium and comprising: a task management table storing a plurality of task combinations, each task combination in the plurality of task combinations comprising at least one task from the plurality of tasks, the task management table comprising at least a listing of tasks stored therein, a unique identifier associated with each task stored therein, and an indication of whether each task stored therein is flagged as being a task that must complete execution prior to switching between task combinations; a processing unit for executing tasks in a present task combination; a judging unit for determining whether there is a task combination switchover request; and a switchover unit for, when the judging unit determines there is a task combination switchover request, switching over from the present task combination to a requested task combination, wherein: the task management table is generated and stored before executing tasks in the present task combination, the judging unit is adapted to determine whether there is a task combination switchover request based on a comparison of pattern numbers associated with the present and requested task combination; when it is judged that the task combination switchover request exists, the judging unit is further adapted to determine whether a not-yet-executed task exists in the current task combination; when it is judged that the not-yet executed task exists, the judging unit is further adapted to judge whether or not there exists a flagged task among the not-yet executed tasks; when it is judged that the flagged task exists in the not-yet-executed task, the processing unit is adapted to continue executing the task in the current task, and when it is judged that the flagged task does not exist in the not-yet-executed task, the switchover unit is adapted to switch over from the present task combination to the requested task combination; and the processing unit is adapted to execute tasks in the requested task combination after the switching over.