3. what is scheduling ? Loading and job sequencing ?

Answer 1

Scheduling is a fundamental aspect of process and resource management in computing and operations. In the context of computer science and operating systems, scheduling refers to the method by which work specified by an operating system is assigned to resources that complete the work. This process ensures that system resources are utilized efficiently to maximize throughput, minimize latency, and ensure fair access among competing processes.

Key Concepts in Scheduling

1. Process Scheduling: This involves managing the execution of processes in a multitasking operating system. The system must decide which process runs at a given time and for how long. Types of scheduling include:

   • Long-term scheduling: Decides which jobs or processes are admitted to the system for processing.
   • Short-term scheduling: Decides which of the ready, in-memory processes are to be executed (or given CPU time) next.
   • Medium-term scheduling: Involves swapping processes in and out of memory to manage the degree of multiprogramming effectively.

2. Scheduling Algorithms: These are strategies used to manage the order and timing of process execution. Common algorithms include:

   • Round Robin: Each process is assigned a fixed time slice in a cyclic order.
   • First-Come, First-Served (FCFS): The process that arrives first is executed first.
   • Shortest Job Next (SJN): The process with the shortest execution time is prioritized.
   • Priority Scheduling: Processes are scheduled based on priority levels; higher priority processes run first.

Loading

Loading refers to the process of bringing programs or parts of programs (usually, code and necessary resources) from secondary storage into primary memory (RAM) so that they can be executed. This involves:

• Static loading: The entire program is loaded into memory before execution.
• Dynamic loading: Portions of a program are loaded into memory only when they are needed during execution.

Job Sequencing

Job Sequencing is a technique used in batch processing or in scheduling where jobs (tasks or processes) will be executed in a specific order. This order can significantly impact the overall efficiency of job execution concerning various criteria such as:

• Total Completion Time: The total time taken to execute all jobs can be minimized by careful sequencing.
• Resource Utilization: Ensuring that jobs requiring specific resources are scheduled when those resources are available.
• Deadlines: Some jobs may have deadlines by which they must be completed. Job sequencing must take these into account to maximize efficiency and meet user expectations.

Summary

In summary, scheduling, loading, and job sequencing are crucial components in operating systems and resource management in computing. They work together to ensure efficient execution of processes, optimal resource utilization, and effective handling of concurrent operations.