Port Mapped I/O
Port Mapped I/O (PMIO) is a method of input/output communication in computer systems where the CPU uses dedicated I/O ports, separate from memory addresses, to interact with peripheral devices. It involves specific instructions (like IN and OUT in x86 architecture) to read from or write to these ports, providing a distinct address space for device control. This approach contrasts with Memory Mapped I/O, where devices are accessed through regular memory addresses.
Developers should learn Port Mapped I/O when working on low-level system programming, embedded systems, or operating system development, as it offers direct and efficient control over hardware devices like serial ports, timers, or interrupt controllers. It is particularly useful in scenarios requiring precise timing, minimal overhead, and isolation from memory operations, such as in real-time systems or legacy hardware interfaces.