The document discusses the boot process of Linux operating systems. When a computer with Linux is turned on, the boot code in ROM loads and starts the kernel. The kernel then probes the system hardware and spawns the system init process. The Linux system can boot automatically or manually. In automatic mode, the complete boot procedure occurs without input, while manual mode involves operator intervention at a certain point before initialization scripts run. The typical Linux boot process involves loading and initializing the kernel, detecting and configuring devices, creating kernel threads, optional operator intervention, running system startup scripts, and achieving multiuser operation.