On the Scheduling of Jobs by Computer

The scheduling of jobs in a factory is one of the problems which offers rich rewards for any satisfactory solution. The aim is to allocate the order in which a set of jobs shall be passed through the factory so that some desirable criterion should be achieved. Each of these jobs requires several operations to be performed, and in many cases these operations can be performed only by certain machines. This is, of course, a combinatorial problem and, like many other similar problems of practical and theoretical interest, the number of possible combinations arising can be very large. Even one of the simplest types of this problem is still formidable. The simple case we consider here is where all the jobs have the same number of operations to be performed and all in the same order. There is also to be the further restriction that once an order of processing shall have been decided, that order shall be maintained throughout all the operations. Thus, the problem is only that of ordering the jobs themselves, and not of ordering the operations within the jobs.