Johnson’s algorithm in regard to sequencing jobs can be further extended for using n jobs through 3 machine case. This can be done with the following conditions-
While following the above conditions, there are certain assumptions which need to be made. These presuppositions are-
In this process, two dummy machines M1 ’ and M3 ’ are presumed in such a way that the operation time of tasks in regard to these machines can be easily calculated.
A job’s processing time on M1 ’ = Total processing time of (M1 + M2 )
A job’s processing time on M2 ’ = Total processing time of (M2 + M1 )
Johnson’s algorithm in regard to sequencing jobs is then applied on M1 ’ and M2 ’ for deriving the most advantageous sequencing of tasks.
Students can have a better understanding of these machines and the processing time of tasks once they start practicing some problems based on the same. Refer to the examples and keep the above conditions and assumptions in mind.