Real-Time Computing with Embedded Linux

Definition and Importance of Real-Time Computing

Real-time computing is crucial in scenarios where tasks must be completed within a strict deadline. This ensures that systems react promptly to external events, maintaining functionality and reliability.

"Real time means that you have a computation which must be completed by some deadline."

Soft vs. Hard Real-Time Systems

In real-time systems, two main categories exist:

Soft Real-Time Systems: These systems allow for some flexibility in meeting deadlines. Missing a deadline might be undesirable but not catastrophic.

"Soft real time, we are a little bit relaxed about missing the deadline."
Hard Real-Time Systems: These require deadlines to be met without exception. Any delay can lead to system failure, making them critical in environments like medical or industrial systems.

"The tricky one is really the hard real time thing. So missing the deadline is never acceptable."

Real-Time Metrics and Determinism

Real-time systems are evaluated based on their ability to consistently meet deadlines. Determinism is a key metric, indicating the predictability of the system's response times.

Preemptive Scheduling and Kernel Preemption

Preemption is a vital feature in Linux for real-time computing, allowing the system to interrupt a process to ensure more critical tasks are completed first.

"The key thing here is preemption within Linux."

For further exploration of embedded systems, visit Defining Embedded Systems and Types of Embedded Computers.