FOR FREE CONTENT
- Introduction: OS
- Booting Process
- Command Interpreter
- Dual mode of operation
- System Calls
- Difference between system call and library call
- Interrupt and Trap
- Introduction
- Scheduling Criteria, Terms and Concepts
- Different Type Scheduling Algorithms
- Longest Job First
- Longest Remaining Time First
- Highest Response Ratio Next (HRRN)
- Priority Scheduling
- Least Completed Next (LCN) Scheduling
- Multi-Level Queue Scheduling
- Multilevel Feedback Queue Scheduling
- Guaranteed Scheduling
- Fair Share Scheduling
- Lottery Scheduling
- Multi-Processor Scheduling
- Deadline Scheduling
- Rate-Monotonic Scheduling
- POSIX Real-Time Scheduling
- Priority Inversion
- Proportional Share Scheduling
- Comparison table of Scheduling Algorithm
- Algorithm Evaluation for Scheduling
- Important concept of MM
- Memory Representation as Address
- Memory layout for a Process
- Logical and Physical Address Space
- Necessity of Memory Management
- Introduction
- Concept of Non-contiguous memory allocation
- Basic concept of Paging
- Address Translation
- Process of Paging Method
- Calculation of Offset for paging
- Calculation of Logical Address Bit and number of Pages
- Calculation of Physical Address Bit and number of Frames
- Calculation of Page Table Size
- Organization of MMU
- Why Page size power of 2
- Paging Address Calculation: example1
- Paging Numeric Problem: Example2
- Paging Address Calculation: Example3
- Paging Address Calculation: Question1
- Some Important Question 2
- Paging Address Translation: Question3
- UGC NET Paging Question
- GATE Paging Question
- Number of information at Page Entry
- Exams Question on Page Entry Information
- Exam Question: Page Entry Information
- Calculates Page Table Entry Size
- Calculates Page Size
- Calculation of Optimal Page Size
- Question on Optimal Page Size
- Hashed Page Table with Example
- Inverted Page Table with Gate Question
- Question on Inverted Page Table
- Multi-Level Paging
- Multi-level paging: Example1
- Multi-level paging: Example2
- Allocation of Frames
- Subject Mock
Real-Time CPU Scheduling
Introduction and properties
The most important feature of a real-time operating system is to respond immediately to a real-time process as soon as that process requires the CPU.
Real-time scheduling must handle two special scheduling constraints while trying to meet the deadlines of applications. First, the processes within a real-time application are interacting processes, so the deadline of an application should be translated into appropriate deadlines for the processes. Second, processes may be periodic i.e. processes always occur at regular intervals.
The timing properties of a real-time CPU Scheduling:
Release time (or ready time): Time at which the task is ready for processing.
Deadline: Time by which execution of the task should be completed after the task is released.
Minimum delay: Minimum amount of time that must elapse before the execution of the task is started after the task is released.
Maximum delay: Maximum permitted amount of time that elapses before the execution of the task is started after the task is released.
Worst case execution time: Maximum time taken to complete the task, after the task is released. The worst case execution time is also referred to as the worst case response time.
Run time: Time taken without interruption to complete the task, after the task is released.
Weight (or priority): Relative urgency of the task.
Subtask structure: A task may be decomposed into a mandatory subtask and an optional subtask. Only mandatory subtask possesses a hard deadline.
