apper" aria-label="Page navigation">
                        <!-- Mobile navigation buttons -->
                        
                            <a rel="prev" href="3_1_communicating_with_the_os.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
                                <i class="fa fa-angle-left"></i>
                            </a>
                        

                        
                            <a rel="next