A multicore processor with 4 cores has 15 attached tape drives. There is a large number of jobs submitted to the system that each requires exactly 4 tape drives to complete execution. Assume that each job runs on 4 tapes for the entire duration of its execution. Also assume an endless supply of such jobs. The scheduler in the operating system will not start a job unless there are 4 tape drives available. When a job is started, 4 drives are utilized immediately for its execution and are not released until the job finishes.

a) What is the maximum number of jobs that can be in progress at once?

b) What are the maximum number of tape drives that may be left idle at a given time as a result of this policy?

c) What are the minimum number of tape drives that may be left idle at a given time as a result of this policy?