.... It was used a set of four LSIs series K1ZHG451...4 (К1ЖГ451...4) or later designation K145HK1...4 (К145ХК1...4). The choice of this calculator as an object of modeling is due to the presence of (miraculously survived to this day) a sufficient set of design documentation for the technology applied in its LSIs, including a technical description of the device, revealing its calculating algorithms. The project is intended for research and education purposes.