Ashrafi Gulam Mohammed, Samsung R
Mallikarjuna Bidari, Samsung R

Inter-process communication (IPC) in an OS has been refactored for various system requirements such as Real Time or General Purpose systems over a period of time. The IPC mechanisms vary to a large extent in these systems so as to meet the system requirements. However, with new era of connected devices called IoT, we see that a system tries to be connected and provide some usability features while staying low on BoM. To stay connected, the system has to cater real-time response requirements especially in case of radio connectivity and if a system has to cater to usability aspects, it has to show some amount of fair scheduling of processes.

Since these aspects are orthogonal in nature for an OS to implement, one possible solution would be to have a system with both operating system co-existing making one of the OS (mostly the RTOS) as master and the other OS hosted as a process on the master OS. A well-known example for this architecture is RTLinux. Apart from many other complications that arise due to co-existence of two OS, an important issue to address is the communication between these two OS. Here the design of system itself makes the communication complicated since the hosted OS is fully pre-emptible and least prioritized making it starve for a long duration if master OS is overloaded. In such situation the hosted OS may delay reading the messages passed by master OS causing overflow and loosing vital information. In this paper we propose a simple shared memory based simplex message passing protocol designed to avoid overflow and protect vital messages.