After splitting the execution of a program image on several threads, and creating a mechanism to dispatch, suspend and resume them, we take the next step on our kernel development by studying and implementing synchronisation mechanisms, namely Sleep/WakeUp, Semaphores, Mutexes and Condition Variables.
With them we can make tasks to work together, by coordinating, enforcing mutual exclusion, and precedence on the access to shared resources – thus guaranteeing these operations to happen on the right sequence at the right time.
These mechanisms facilitate the development of complex applications, by effectively allowing the decomposition of a complex job on several tasks that cooperate. Our kernel is taking shape.
*a more technical term for small is “constrained”
A GitHub repo with the source code for the presented kernel can be found in:
https://github.com/antoniogiacomelli/ertos
Electronics, Computer and Embedded Software Engineering 