*Smallest sequence of programmed instructions that can be managed independently by a [scheduler](https://en.wikipedia.org/wiki/Scheduling_(computing))*
From <[https://en.wikipedia.org/wiki/Thread_(computing)](https://en.wikipedia.org/wiki/Thread_(computing))>
- Instructions run independently by scheduler
- Single address space
- One thread blocked for I/O
- Tasks run in other threads
- Need locks and mutexes
- Coordination between threads
- Complicated
- Deadlocks
# Protothreads
- Lightweight
- Stack-less
- Interruptible tasks for event-based
- Conditional blocking statement
- Blocks until given statement is true
- Use timer to manage
- Invoked whenever process receives message from another process or timer
# Events
*Action or occurrence recognized by software, often originating asynchronously from the external environment, that may be [handled](https://en.wikipedia.org/wiki/Event_handler) by the software*
From <[https://en.wikipedia.org/wiki/Event_(computing)](https://en.wikipedia.org/wiki/Event_(computing))>
