Premptive Scheduling Vs Non-premptive Scheduling

The scheduling which takes place when a process switches from running state to ready state or from waiting state to ready state is called Preemptive Scheduling. On the hands, the scheduling which takes place when a process terminates or switches from running to waiting for state this kind of CPU scheduling is called Non-Preemptive Scheduling. The basic difference between preemptive and non-preemptive scheduling lies in their name itself. That is a Preemptive scheduling can be preempted; the processes can be scheduled. In Non-preemptive scheduling, the processes can not be scheduled.

Key Differences Between Preemptive and Non-Preemptive Scheduling:

  1. The basic difference between preemptive and non-preemptive scheduling is that in preemptive scheduling the CPU is allocated to the processes for the limited time. While in Non-preemptive scheduling, the CPU is allocated to the process till it terminates or switches to waiting state.
  2. The executing process in preemptive scheduling is interrupted in the middle of execution whereas, the executing process in non-preemptive scheduling is not interrupted in the middle of execution.
  3. Preemptive Scheduling has the overhead of switching the process from ready state to running state, vise-verse, and maintaining the ready queue. On the other hands, non-preemptive scheduling has no overhead of switching the process from running state to ready state.
  4. In preemptive scheduling, if a process with high priority frequently arrives in the ready queue then the process with low priority have to wait for a long, and it may have to starve. On the other hands, in the non-preemptive scheduling, if CPU is allocated to the process with larger burst time then the processes with small burst time may have to starve.
  5. Preemptive scheduling is quite flexible because the critical processes are allowed to access CPU as they arrive into the ready queue, no matter what process is executing currently. Non-preemptive scheduling is rigid as even if a critical process enters the ready queue the process running CPU is not disturbed.
  6. The Preemptive Scheduling is cost associative as it has to maintain the integrity of shared data which is not the case with Non-preemptive Scheduling.

Conclusion:

It is not that preemptive scheduling is better than non-preemptive scheduling or vise-verse. All depends on how a scheduling minimizes the average waiting time of the processes and maximizes CPU utilization.

Comments

Post a Comment

Popular posts from this blog

Process Vs Thread

The Process and Thread are the essentially correlated. The process is an execution of a program whereas thread is an execution of a program driven by the environment of a process. Another major point which differentiates process and thread is that processes are isolated with each other whereas threads share memory or resources with each other. Key Differences Between Process and Thread : All threads of a program are logically contained within a process. A process is heavy weighted, but a thread is light weighted. A program is an isolated execution unit whereas thread is not isolated and shares memory. A thread cannot have an individual existence; it is attached to a process. On the other hand, a process can exist individually. Each thread has its own stack, so if a thread dies its stack is reclaimed. In contrast, if a process dies, all threads die including the process. Conclusion: Processes are used to achieve execution of programs in concurrent and sequential manner.
Read more

Reasoning Vs Inference

Inference: Inference is a general term representing the derivation of new knowledge from existing knowledge and axioms (i.e., rules of derivation) within a single step, and can be one of many kinds, such as, induction, deduction and abduction. For example, "modus tollens" is a rule of inference. Thus, one inference is the derivation of new knowledge using a single step using modus tollens. Inference is about taking in data and trying to draw a conclusion based on the limited information you have in a situation where not all the data is given. Reasoning: Reasoning is in context of a goal (e.g., decide whether a propositional formula is satisfiable or not)  and is carried out via a search process involving multiple inferences. Choices during such search have to be made such as which axiom to "fire" along with which knowledge in order to derive new knowledge. Resolution is a particular kind of reasoning involving the "resolution rule". Reasoning is
Read more

Frame vs Packet

Image
Difference Between Frame and Packet     The crucial difference between frame and packet is that frame is the serial collection of bits, and it encapsulates packets whereas packets are the fragmented form of data and it encapsulates segment. Data link layer performs framing process. On the other hand, Network layer performs fragmentation of the data and create smaller chunks known as packets. Another major difference is that a frame includes device’s MAC address while a packet includes device’s IP address. Basis for comparison Frame Packet Basic Frame is the data link layer protocol data unit. Packet is the network layer protocol data unit. Associated OSI layer Data link layer Network layer Includes Source and destination MAC address. Source and destination IP address. Correlation Segment is encapsulated within a packet. Packet is encapsulated within a frame. Conclusion: Frames and Packets function as protocol data units utilized on the
Read more