In this chapter, the following content will be discussed: Introduction, windows NT as a real-time OS, real-time features of windows NT, observations and recommendations, windows NT in a real-time setting, Summary. | Chapter 15 Specification of Software Components Page Building Reliable Component-based Systems Chapter 15 - Specification of Software Components Overview Introduction Windows NT as a real-time OS Real-time features of windows NT Observations and recommendations Windows NT in a real-time setting Summary Page Building Reliable Component-based Systems Chapter 15 - Specification of Software Components Introduction Windows NT is presented from the perspective of real-time constraints. Address the following questions: What type of applications can use Windows NT, as is? Can the unpredictable parts of NT be “masked”? Page Building Reliable Component-based Systems Chapter 15 - Specification of Software Components Windows NT as a Real-Time OS The original design of NT was based on a micro-kernel, common to many real-time operating systems. During the evolution a limited number of real-time features have been incorporated: IDLE, NORMAL, HIGH and REALTIME. The REALTIME priority . | Chapter 15 Specification of Software Components Page Building Reliable Component-based Systems Chapter 15 - Specification of Software Components Overview Introduction Windows NT as a real-time OS Real-time features of windows NT Observations and recommendations Windows NT in a real-time setting Summary Page Building Reliable Component-based Systems Chapter 15 - Specification of Software Components Introduction Windows NT is presented from the perspective of real-time constraints. Address the following questions: What type of applications can use Windows NT, as is? Can the unpredictable parts of NT be “masked”? Page Building Reliable Component-based Systems Chapter 15 - Specification of Software Components Windows NT as a Real-Time OS The original design of NT was based on a micro-kernel, common to many real-time operating systems. During the evolution a limited number of real-time features have been incorporated: IDLE, NORMAL, HIGH and REALTIME. The REALTIME priority class is available as a support for real-time applications. The base priority for the REALTIME class includes levels 16 to 31. Levels 17 to 21 and 27 to 30 are currently not used by the scheduler. Page Building Reliable Component-based Systems Chapter 15 - Specification of Software Components Windows NT Priority Structure Interrupts Deferred Procedure Calls (DPC) Time Critical NA Highest Above Normal Normal Below Normal Lowest NA Idle 31 26 25 24 23 22 16 15 0 Time Critical Normal Foreground Normal Background Below Normal Idle Idle Thread Real-Time Priority Class Dynamic-Time Priority Classes Decreasing Priority Page Building Reliable Component-based Systems Chapter 15 - Specification of Software Components Scheduling Priority based preemptive scheduling: The highest priority active task is chosen for execution possibly interrupting the execution of another task. Base priority REALTIME: non-degradable priorities NORMAL/HIGH can be delayed For this reason the latter priority .
