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SCAN
SCAN (Single Instruction, Multiple Access): SCAN is a scheduling algorithm used in operating systems to manage the access of multiple processes or threads t...
SCAN (Single Instruction, Multiple Access):
SCAN is a scheduling algorithm used in operating systems to manage the access of multiple processes or threads to a shared resource. It allows the resource to be used efficiently by minimizing conflicts and maximizing utilization.
The process of accessing the resource in this algorithm involves the following steps:
Identification: Each process or thread submits a request to access the shared resource.
Queueing: Requests are stored in a queue in the order they are received.
Resource Allocation: Once the resource becomes free, the operating system picks the next request from the queue.
Completion: The resource is released by the process that completed the access.
Example:
Imagine a computer with 4 available hard disk tracks, which are used to store data. Two processes, P1 and P2, are waiting to access the hard disk.
P1:
Submits a request to access track 1.
Waits in the queue for its turn.
Gets allocated track 1.
Completes access and releases track 1.
P2:
Submits a request to access track 2.
Waits in the queue for its turn.
Gets allocated track 2.
Completes access and releases track 2.
Benefits of SCAN:
Efficiency: Reduces contention by allowing multiple processes to access the resource concurrently.
Resource utilization: Maximizes utilization of the shared resource by allocating it to the process that needs it the most.
Simple implementation: The algorithm is relatively straightforward to implement.
Note:
SCAN is a basic scheduling algorithm and may not be suitable for all scenarios. Other scheduling algorithms, such as priority-based scheduling, can be used to address specific performance requirements