Explain the different types of CPU scheduling algorithms in Operating System.
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Operating systems manage memory allocation for applications through various techniques to ensure efficient usage and prevent issues like memory leaks and fragmentation. Memory Allocation Techniques: 1. Contiguous Allocation: Memory is allocated in contiguous blocks. Operating systems use techRead more
Operating systems manage memory allocation for applications through various techniques to ensure efficient usage and prevent issues like memory leaks and fragmentation.
Memory Allocation Techniques:
1. Contiguous Allocation:
Memory is allocated in contiguous blocks. Operating systems use techniques like segmentation (dividing memory into logical segments) and paging (dividing memory into fixed-size pages) to manage memory for applications.
2. Dynamic Allocation:
OS dynamically allocates memory based on application demands using techniques like:
– Heap Management:
Allocating memory from the heap as requested by applications. Techniques such as first-fit, best-fit, and worst-fit algorithms are used to find suitable memory blocks.
– Stack Management:
Allocating memory for function calls and local variables, managed using a stack data structure.
3. Preventing Memory Leaks:
Memory leaks occur when applications allocate memory but fail to release it after use, gradually depleting available memory. Techniques to prevent leaks include:
– Garbage Collection:
Automatic memory management where the OS periodically identifies and reclaims memory no longer in use.
– Manual Memory Management:
Encouraging developers to explicitly free allocated memory when it’s no longer needed.
4. Preventing Fragmentation:
Fragmentation occurs when memory becomes divided into small, unusable segments over time, reducing available contiguous memory. Techniques to prevent fragmentation include:
– Compaction:
Periodically rearranging memory to consolidate free space.
– Memory Pools:
Allocating fixed-size memory blocks for specific purposes to reduce fragmentation.
– Memory Reclamation:
Releasing unused memory back to the OS to manage larger contiguous blocks.
By implementing these techniques, operating systems can efficiently manage memory allocation, minimize issues like leaks and fragmentation, and ensure reliable performance for applications.
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First Come First Serve First Come First Serve is the full form of FCFS. It is the easiest and most simple CPU scheduling algorithm. In this type of algorithm, the process which requests the CPU gets the CPU allocation first. This scheduling method can be managed with a FIFO queue. Shortest RemainingRead more
First Come First Serve
First Come First Serve is the full form of FCFS. It is the easiest and most simple CPU scheduling algorithm. In this type of algorithm, the process which requests the CPU gets the CPU allocation first. This scheduling method can be managed with a FIFO queue.
Shortest Remaining Time
The full form of SRT is Shortest remaining time. It is also known as SJF preemptive scheduling. In this method, the process will be allocated to the task, which is closest to its completion. This method prevents a newer ready state process from holding the completion of an older process.
Priority Based Scheduling
priority scheduling is a method of scheduling processes based on priority. In this method, the scheduler selects the tasks to work as per the priority.
Priority scheduling also helps OS to involve priority assignments. The processes with higher priority should be carried out first, whereas jobs with equal priorities are carried out on a round-robin or FCFS basis. Priority can be decided based on memory requirements, time requirements, etc.
As the process enters the ready queue, its PCB (Process Control Block) is linked with the tail of the queue. So, when CPU becomes free, it should be assigned to the process at the beginning of the queue.
Round-Robin Scheduling
Round robin is the oldest, simplest scheduling algorithm. The name of this algorithm comes from the round-robin principle, where each person gets an equal share of something in turn. It is mostly used for scheduling algorithms in multitasking. This algorithm method helps for starvation free execution of processes.
Shortest Job First
SJF is a full form of (Shortest job first) is a scheduling algorithm in which the process with the shortest execution time should be selected for execution next. This scheduling method can be preemptive or non-preemptive. It significantly reduces the average waiting time for other processes awaiting execution.
Shortest Job First
SJF is a full form of (Shortest job first) is a scheduling algorithm in which the process with the shortest execution time should be selected for execution next. This scheduling method can be preemptive or non-preemptive. It significantly reduces the average waiting time for other processes awaiting execution.
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