9 Jobs arrive to a file server consisting of a CPU and two disks (disk 1 and disk 2). Currently there are six clients, and an average of three jobs per second arrive. Each visit to the CPU takes an average of .01 second, each visit to disk 1 takes an average of .02 second, and each visit to disk 2 takes an average of .03 second. An entering job first visits the CPU. After each visit to the CPU, with probability 7/16 the job next visits disk 1, with probability 8/16 the job next visits disk 2, and with probability 1/16 the job is completed.

After visiting disk 1 or 2, the job immediately returns to the CPU.

a On the average, how many times does a job visit the CPU? How about disk 1? How about disk 2?

b On the average, how long does a job spend in the CPU? How long in disk 1? How long in disk 2? How long in the system?