This book serves as a textbook on computer architecture and operating systems, based on the lecture course "Computer Architecture and Assembly Language" taught to students of the Faculty of Computational Mathematics and Cybernetics at Moscow State University named after M.V. Lomonosov. While there is a considerable body of literature on programming in Assembly language, there is a noticeable lack of dedicated educational resources specifically focused on computer architecture and system programming. Moreover, existing texts tend to be aimed primarily at technical colleges rather than universities. This book aims to fill that gap. Alongside computer architecture, the textbook also covers low-level programming with Assembly language. This focus is driven by the fact that a computer executes algorithms directly in machine language, making knowledge of Assembly—closely related to machine code—essential for a deeper understanding of computer architecture. Intended primarily for students in higher education institutions, the book can also be used for self-study of the fundamentals of computer architecture and system programming. It has been developed in accordance with the Federal State Educational Standards for programs in "Applied Mathematics and Informatics" and "Fundamental Informatics and Information Technologies" (bachelor's degree level).