1How are external I/O devices categorised?
External I/O devices can be categorised into Human readable, Machine readable, and Communications devices
2Explain Programmed I/O.
In Programmed I/O, the processor issues an I/O command and then busy waits for the I/O operation to complete
3Explain Interrupt-Driven I/O.
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
4Explain Direct Memory Access (DMA).
DMA allows data to be transferred directly between main memory and an I/O module without constant processor involvement
5Why is I/O buffering required?
I/O buffering resolves inefficiencies like slow I/O waits and deadlocks, improving system and process performance
6Differentiate between Block-oriented and Stream-oriented I/O devices.
Block-oriented devices use fixed-size blocks for data transfer, while stream-oriented devices handle data as a continuous stream of bytes
7Explain the concept of "Single Buffering" for block-oriented data.
Single Buffering uses one buffer in system memory for I/O transfers, allowing reading ahead or writing via the buffer
8What is "Double Buffering" or "Buffer Swapping"?
Double Buffering lets a process use one buffer while the OS handles another, allowing non-blocking I/O
9When is a "Circular Buffer" used?
A Circular Buffer is used when more than two buffers are needed, supporting continuous data transfer in a circular fashion