lammert - 6:52 pm on Mar 29, 2010 (gmt 0)
This kind of planning software with automatic scheduling and rearrangements of tasks and resources exists, but I have seen it only in the high end planning systems for enterprises. You often pay 6 figures for it. Automatic rescheduling of tasks is often only possible if you are quite sure of the capacity and capabilities of all systems and humans involved. For machinery this can often be computed. For humans it is most of the time impossible. Some tasks may cost one person 40 hours, the other person only 10 and a third person may not be able to complete the task at all. You may have two projects which are so similar that you can assign them to one person at once and they will cost only a little bit more than the time of one project to complete. But other projects can be difficult to schedule together with other projects because they need a specific mindset.
When it comes to planning I often try to determine the critical path. Which tasks can only be executed sequentially and which factors (often delivery times of external suppliers) will have the largest effect on delaying the project? I then monitor the critical path closely. The other less critical tasks will often automatically complete within schedule and need less attention.