I/O

Question 1

What are the three techniques of I/O?

Answer 1

Programmed I/O
Interrupt-driven I/O
Direct memory access (DMA)

Question 2

Describe Programmed I/O

Answer 2

the CPU directly manages the data transfer between the I/O device and memory.

Question 3

Describe Interrupt-driven I/O

Answer 3

when an I/O device has completed a task or needs attention, it sends an interrupt signal to the CPU, prompting it to pause what it’s doing and handle the I/O request.

Question 4

Describe DMA

Answer 4

A DMA controller takes over the data transfer task between an I/O device and memory, allowing the CPU to continue with other tasks.

Question 5

What is I/O Buffering?

Answer 5

Using a holding area to temporarily store data being transferred between an I/O device and the main memory or CPU.

Question 6

Why do we buffer?

Answer 6

Buffering helps smooth out the differences in data transfer rates between devices, allowing for more efficient and streamlined data processing.

Question 7

What are the two types of Buffering?

Answer 7

Block oriented and Stream Oriented.

Question 8

Three Categories of I/O Devices

Answer 8

1. Human-readable
2. Machine Readable
3. Communication

Question 9

Describe Block Oriented Buffering.

Answer 9

Information is stored in fixed sized blocks
Transfers are made a block at a time
Used for disks and USB keys

Question 10

Describe Stream- oriented buffering

Answer 10

Transfer information as a stream of bytes
Used for terminals, printers, communication ports, mouse and other pointing devices, and most other devices that are not secondary storage