Question

1) Why is scheduling fairly simple for repetitive systems but fairly complex for job shops? 


6)Why are priority rules needed in scheduling?

Answer 1

1) The decision of the system is pretty much pre-determined and in a structured form in case of repetitive system. As the activities and the equipments are very simple so it becomes easier to use scheduling in repetitive system. It can also be because high and medium volume has same type of production system which helps to have simple scheduling. Hence, scheduling is simple in repetitive systems due to it's structured and repeatative form.

On the other hand, the job shop production is not a mass production and it needs customization based on the needs and demand of the clients and that of order requirements. So, as each of the orders varies, the schedulers face difficulty while putting objectives. Besides, the sequence of the job processes is also differs.

6) The most important role of priority rules is that it provides guidelines to the scheduling process in which it is going to work. When the scheduling issues occurs due to incomplete work or inefficient job performance, the priority rules guide the scheduling process and determines which rule is important. Such as with the help of LPT, schedulers can reduce the job timings and adjust the schedule. FCFS simplifies the job sequencing.

Hope this helps :)