Consider a computer system to which two types ofcomputer jobs are submitted. The mean time to run eachtype of job is m1. The interarrival times for each type of jobare exponential, with an average of li type i jobs arrivingeach hour. Consider the following three situations. a Type 1 jobs have priority over type 2 jobs, and pre-emption is allowed. b Type 1 jobs have priority over type 2 jobs, and nopreemption is allowed.c All jobs are serviced on a FCFS basis.Under which system are type 1 jobs best off? Worst off?Answer the same questions for type 2 jobs.
Consider a computer system to which two types of
computer jobs are submitted. The mean time to run each
type of job is m
1
. The interarrival times for each type of job
are exponential, with an average of li type i jobs arriving
each hour. Consider the following three situations.
a Type 1 jobs have priority over type 2 jobs, and pre-
emption is allowed.
b Type 1 jobs have priority over type 2 jobs, and no
preemption is allowed.
c All jobs are serviced on a FCFS basis.
Under which system are type 1 jobs best off? Worst off?
Answer the same questions for type 2 jobs.
Priority job scheduling is a technique used to manage resources in a computer system. This technique assigns a priority value to each job or task that needs to be executed in the system. The higher the priority value, the more important the job is considered to be. When a new job enters the system, the scheduler compares its priority value to the priorities of other jobs currently waiting to be executed. If the new job has a higher priority than the others, it is executed first. This ensures that high-priority jobs are completed as quickly as possible.
There are several types of priority scheduling algorithms, including:
-
Preemptive priority scheduling
-
Non-preemptive priority scheduling
-
Dynamic priority scheduling
A priority scheduling algorithm is used to manage resources in a computer system. In this case, the system is designed to handle two types of jobs, type 1 and type 2. The interarrival times for each type of job are modeled using an exponential distribution, with an average rate of arrival for each type of job. In situation (a), the system is designed to prioritize type 1 jobs over type 2 jobs, and preemption is allowed. This means that if a type 1 job arrives while a type 2 job is currently executing, the system will interrupt the execution of the type 2 job and switch to running the type 1 job. This ensures that type 1 jobs are given priority and are executed as quickly as possible.
The mean time to run each type of job is also an important parameter in this system. This parameter represents the average amount of time it takes to complete a job of a particular type. If the mean time to run type 1 jobs is significantly longer than the mean time to run type 2 jobs, the system may need to allocate more resources to type 1 jobs to ensure they are completed in a timely manner. Overall, situation (a) illustrates the importance of using priority scheduling algorithms to manage resources in computer systems. By prioritizing certain types of jobs, it is possible to optimize system performance and ensure that critical tasks are completed in a timely manner.
So, in this case type 1 jobs have priority over type 2 jobs and preemption is allowed. Type 2 jobs can be preempted if a type 1 job arrives, and the system will switch to running the type 1 job. Type 1 jobs are best off in this system because they have priority and can interrupt type 2 jobs, which may cause a delay in the completion of type 2 jobs. On the other hand, type 2 jobs are worst off because they may be preempted by type 1 jobs and have to wait for type 1 jobs to complete before being executed.
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