This article is devoted to the study of the possibilities of optimizing the operability and improving the efficiency of complex multifunctional software systems using the example of free automated library and information systems (hereinafter - ALIS).

By 2023, the world has accumulated valuable experience in the creation and operation of integrated ALIS of various scales and purposes, but the issues of improving their design solutions remain relevant. First of all, this concerns the need to optimize the structure of the source code in order to increase its readability and maintainability, reduce the execution time of individual functional modules, and reduce the amount of RAM used.

As part of the study, a comparative analysis of the source codes of several existing open source databases implemented in various programming languages was carried out. The main approaches to the design of the code structure were studied, the most frequently used algorithms and patterns were identified. To assess the degree of optimization of the source code, a set of indicators was developed, including an assessment of the structure, readability, modularity and other characteristics. On this basis, individual code fragments were compared before and after the use of well-known refactoring techniques.

As a result of the work carried out, it was possible to identify the most common errors and shortcomings in the structuring of the source codes of the ALIS, to determine the main directions of their optimization. Data has been obtained on the possible reduction of testing and technical support costs by improving the quality of source codes.

The article is devoted to automation of the software design stage. In the course of the study, the reasons for the high importance of this stage and the relevance of its automation were analyzed. The main stages of this stage were also considered and the existing systems that allow automating each of them were considered. In addition, an own solution was proposed within the framework of the problem of class structure refactoring based on the combinatorial optimization method. A solution method has been developed to improve the quality of the class hierarchy and tested on a real model.