How OS communicates with and manages hardware devices
Operating systems interact with hardware through various mechanisms that abstract device complexities while providing efficient access to system resources. The primary hardware interaction methods include programmed I/O (CPU directly controls devices through port instructions), interrupt-driven I/O (devices signal completion via interrupts), direct memory access (DMA controllers transfer data directly between devices and memory without CPU involvement), and memory-mapped I/O (device registers appear as memory locations). Device drivers serve as hardware-specific software components that translate OS requests into device-specific operations. The OS manages hardware resources through device controllers, which interface between the system bus and physical devices. Interrupt handling is a critical aspect where the OS responds to hardware events by saving context, servicing the interrupt, and restoring execution. Modern systems also use advanced configuration and power interface (ACPI) for power management and device configuration. Hardware abstraction layers (HAL) provide uniform interfaces to diverse hardware, enhancing portability. Understanding hardware interaction is essential for system developers and driver writers, as it impacts system performance, power efficiency, and compatibility across different hardware platforms.