What is an embedded system?
A special computer system designed to perform a small set of designated tasks.
Embedded markets and applications include:
- Network devices
- Mobiles/PDAs and consumer electronics
- Audio/Video and signal processing
- Industrial and home automation
- Aerospace & Defense
Embedded systems typically use real time operating systems (RTOS). A RTOS has a deterministic behaviour, that is, it responds within a guaranteed amount of time. This behaviour is characterized in terms of jitter, the variability of the system's response time, and latency, the delay between an event and its action.
A hard real time system will always be deterministic, responding with a given latency and a known jitter, while a soft real time system will make a best effort to be deterministic. It is assumed that exceeding the nominal latency or jitter is not catastrophic on a soft real time system.
Linux is a general purpose operating system (GPOS) which can be enhanced to offer soft real time response times, and even hard real time responses for some applications.