Week 8 - Input and Output Management

External I/O devices can be categorised into Human readable, Machine readable, and Communications devices

In Programmed I/O, the processor issues an I/O command and then busy waits for the I/O operation to complete

In Interrupt-Driven I/O, the processor issues an I/O command and continues executing other tasks until interrupted by the I/O module upon completion

DMA allows data to be transferred directly between main memory and an I/O module without constant processor involvement

I/O buffering resolves inefficiencies like slow I/O waits and deadlocks, improving system and process performance

Block-oriented devices use fixed-size blocks for data transfer, while stream-oriented devices handle data as a continuous stream of bytes

Single Buffering uses one buffer in system memory for I/O transfers, allowing reading ahead or writing via the buffer

Double Buffering lets a process use one buffer while the OS handles another, allowing non-blocking I/O

A Circular Buffer is used when more than two buffers are needed, supporting continuous data transfer in a circular fashion