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Support for Legacy Real-Time Applications in an HSF-Enabled FreeRTOS - a technical report


Publication Type:

Report - MRTC


Mälardalen Real-Time Research Centre, Mälardalen University




This paper presents a runtime support to consolidate legacy together with other real-time applications, running a single instance of a real-time operating system (RTOS), and sharing system resources. In this context, we resort to the hierarchical scheduling framework (HSF) to provide tem- poral partitions for di erent applications, supporting their independent development and real-time analysis, thus resulting on a predictable inte- gration. In particular, the paper focuses on a constructive element, the legacy server that allows executing code that is unaware of the temporal partition within which it is deployed. Furthermore, we discuss the chal- lenges that need to be addressed to execute a legacy application in an HSF without modi cations to the original code. We focus on the chal- lenge of enabling sharing system resources, both hardware and software, as typically found in most industrial software systems. We propose a novel solution based on wrappers for the required RTOS system calls. We implement our ideas in a concrete implementation on FreeRTOS OS, taking advantage of a prior HSF implementation. The validation is performed by a proof-of-concept case study that shows a successful integration of a legacy application that uses shared resources in a system that executes other applications.


author = {Rafia Inam and Moris Behnam and Mikael Sj{\"o}din},
title = {Support for Legacy Real-Time Applications in an HSF-Enabled FreeRTOS - a technical report},
month = {November},
year = {2014},
publisher = {M{\"a}lardalen Real-Time Research Centre, M{\"a}lardalen University},
url = {}