Input/Output Devices Overview

Hardware devices that can input data, output data, or manage data processing.

Software modules that enable communication between an I/O device and the operating system.

A connection point where I/O devices connect to the system.

A set of wires and a communication protocol that allows multiple devices to share the same connection.

Intended for communicating with human users, like keyboards and mice.

Intended for communicating with electronic equipment, like sensors and controllers.

Intended for communicating with remote devices, like modems and network cards.

A serial bitstream is converted into blocks of bytes, and error correction is applied. This process is done by the device driver.

The amount of data transferred from one location to another in a specific time.

The specific use of a device, often tied to its intended purpose.

The difficulty in operating and controlling the device.

The size and method of data transfer. Data can be transferred as a stream of bytes (character devices) or large blocks (block devices).

How data is encoded and represented by the device, involving character codes and parity conventions.

The types of errors that can occur, how they are reported, their consequences, and possible responses.

A device that stores information in fixed-size blocks, transferring data one block at a time. Examples: Hard disks, Flash drives.

A device that transfers data as a continuous stream of bytes. Examples: Keyboards, Mice.

A device that transfers data as a continuous stream of bytes without any block structure. Examples include network cards, printers, and scanners.

This layer converts I/O requests into a series of instructions, commands, and control signals that the device can understand.

This layer manages the queue and timing of I/O operations, handles interrupts, and monitors device status.

The processor directly communicates with the I/O device, checking its status and transferring data in a cycle. It's simple but can be inefficient.

The processor sends an I/O command and continues executing other instructions, only being interrupted when the device is ready.

The DMA module handles data transfer between memory and the device, freeing the processor for other tasks. This improves efficiency for large data transfers.

The structure of communication devices is similar to I/O devices, but with a communication architecture layer instead of a logical I/O layer.

A data transfer technique where blocks of data are transferred between memory and I/O devices, often managed by a DMA controller.

This layer handles I/O operations for user processes, providing a simple interface using device identifiers and commands.

This layer handles the physical connection between the I/O device and the system, managing registers and status flags.

This I/O size is a common optimization strategy for applications, allowing them to transfer larger amounts of data in a single operation.

This technique involves using double buffering to improve I/O performance. One buffer is filled or emptied while the other is being used.

These parameters are used to define the size and format of the data being transferred.

This refers to the process of mapping addresses to devices, allowing the system to communicate with the correct device.

A disk scheduling policy where requests are processed in the order they arrive (first come, first served). It's simple but can lead to inefficient disk head movement if requests are clustered.

A disk scheduling policy where the most recent request is processed first. Useful for transaction systems where the newest data needs quick access.

A disk scheduling policy where the disk head moves in one direction, servicing requests as it goes, then reverses direction and services requests on the way back. This minimizes the time the head spends moving across the disk.

A variation of SCAN that segments the disk request queue into smaller queues, processing each queue in its entirety before moving to the next. This balances the need for fairness with performance.

A disk scheduling policy that uses two queues to handle requests. While one queue is being processed, new requests are added to the other, minimizing waiting time.

A storage technique that combines multiple disks into a single logical unit, offering increased performance and fault tolerance.

A RAID level that stripes data across multiple disks, providing faster read speeds but no data redundancy.

A RAID level that mirrors data across multiple disks, providing high data redundancy but slower write speeds.

A RAID level that stripes data across multiple disks and uses a parity block for data recovery, offering a balance between performance and redundancy.

A memory component that temporarily stores frequently accessed data for faster retrieval.

A temporary storage area in main memory used to speed up disk access by storing recently accessed data.

A principle that states that data accessed recently or frequently is likely to be accessed again soon.

A technique that improves system performance by storing the results of frequently performed operations in a local cache for future use, avoiding unnecessary recalculations.