Embedded development: embedded foundation -- threads and tasks

　　32 The function of bit microcontroller is getting stronger , The cost is getting lower , This makes the real-time operating system become the main scheduler in many embedded systems . Although there are more than 100 different kinds in the market RTOS taste , But embedded developers sometimes struggle with basic terminology . Take threads and tasks for example , They are used as synonyms in many cases , But it means a slightly different concept .

　　ThreadX User guide page 5 Version defines embedded tasks as “ Semi independent parts of an application that perform specific tasks ” let me put it another way , Tasks are often high-level tasks performed by applications .“ Mission ” This word is often used in a general way , So that it is difficult to determine whether the developer refers to a program segment or a completely independent loadable program .

　　

 

　　 On the other hand , Threads are defined as “ Semi independent program segments executed in process ”. For embedded developers who use microcontrollers , A process is essentially the entire application running on the system . Thread is a small program , It has specific functions and uses in the whole application . Threads are often lower than the task level , The cost is also minimal .

　　 Most people encounter RTOSes It may actually be a thread scheduler , Instead of task scheduler , But now many embedded developers just use these two terms interchangeably . I'm glad to know that there is a subtle difference .