Lesson 3 Flashcards
The component of the operating system responsible for selecting which process from the ready queue should be executed next by the CPU. It makes decisions based on a defined scheduling algorithm.
CPU Scheduler/Short Term Scheduler
The module that gives control of the CPU to the process selected by the CPU scheduler. It involves switching context, switching to user mode, and jumping to the proper location in the user program.
Dispatcher
The time taken from when the scheduler selects a process to execute until CPU starts executing that process. This includes context switching and any overhead involved in the dispatching process.
Dispatch Latency
The metrics used to evaluate and compare the performance of different scheduling algorithms.
Scheduling Criteria
The number of processes completed per time unit.
Throughput
The total time taken from submission of a process to its completion.
Turn Around Time
The total time a process spends waiting in the ready queue.
Waiting Time
The time from when a request is submitted until the first response is produced, not counting the time for the output to be used.
Response Time
A scheduling algorithm that serves processes in the order they arrive in the ready queue, like a queue at a ticket counter. It is simple but can lead to long waiting times, especially if short processes are stuck behind long ones.
First Come First Serve (FCFS)
An algorithm that selects the process with the smallest execution time first. This can minimize turnaround time but can lead to the “starvation” of longer processes.
Shortest Job First (SJF)
A scheduling method where processes are assigned priorities, and the CPU is allocated to the process with the highest priority (lowest numerical value). If two processes have the same priority, FCFS is applied. It can lead to starvation for low-priority processes.
Priority Scheduling
A preemptive scheduling algorithm where each process is assigned a fixed time slice (quantum) in which it can execute. Once the time sliced is used up, the process is placed at the end of the ready queue, and the next process is given CPU time. This method is far and effective time sharing.
Round Roubin (RR)
The amount of time a process spends executing on the CPU before it either blocks (waiting for I/O) or voluntarily yields control of the CPU.
CPU Burst
The total time required by a process for its execution on the CPU, from start to finish.
Burst Time
Refers to the measures taken to protect a system, network, or information from unauthorized access, theft, damage, or disruption.
Security
Encompass the types of breaches or attacks that compromise confidentiality, integrity, or availability.
Security Violation Categories
Occurs when unauthorized access exposes private or sensitive information.
Breach of Confidentiality
Happens when data is altered or tampered with without authorization.
Breach of Integrity
Occurs when legitimate users are denied access to resources or systems.
Breach of Availability
Refers to unauthorized use of a system’s resources or services.
Theft of Service
Is an attack that disrupts the normal functioning of a service, making it unavailable to legitimate users.
Denial of Service (DoS)
Methods used to compromise a system’s security, including techniques like masquerading, replay attacks, and session hijacking
Security Violation Method
Involves pretending to be another entity to gain unauthorized access
Masquerading
Occurs when valid data transmission is intercepted and resent by an attacker to deceive a system.
Replay Attack
