Industrial Automatic Control Systems and Controllers Annotation << Back Justification of the Need to Switch the Automated Control System to Domestic Software P.Yu. Pushkin, P.I. Karasev, M.Yu. Titov, A.G. Ivanov The article discusses the possibility of switching from established software to free software. The overwhelming majority of government and private organizations to fulfill the compliance requirements of software choose proprietary software products the dominant part of which are foreign solutions. By doing this, companies incur additional economic costs and, due to the unavailability of the source code, do not receive security guarantees. For partial solve of these problems, it is possible to use free software. The government takes an active part in the processes of creating and developing national software based on free software, which regularly creates and makes changes to normative documents and projects for the implementation of import substitution policy. In order to get answers to questions about the relevance of taking actions aimed at partially or completely replacing the used software with free software, the necessary tests were carried out. The research results obtained in this way allow us to note the most important shortcomings of the system at the moment, as well as to identify cases as a result of which the existing shortcomings can be neglected. In addition, it becomes possible to give an objective assessment of the reasonability of such actions aimed at implementing the import substitution policy at the government level. Keywords: free software, operating systems, import substitution, testing, analysis, russian software, OS Linux. DOI: 10.25791/asu.6.2022.1371 Pp. 36-40.