Input and Output Management

Practice vocabulary flashcards covering Input/Output management, DMA configurations, and buffering techniques based on the lecture notes.

Human-readable devices

External devices categorized for communication with the user, including printers, visual display terminals, keyboards, and mice.

Machine-readable devices

External devices intended for communication with equipment, such as disk and tape drives, sensors, and actuators.

Communications devices

External devices such as modems used for transmitting data between different systems.

Programmed I/O

An I/O organization method where the processor issues a command on behalf of a process to an I/O module and then busy waits for the operation to complete.

Interrupt-Driven I/O

An I/O organization method where the processor issues a command, continues to execute other instructions, and is interrupted by the I/O module only when the operation is finished.

Direct Memory Access (DMA)

An I/O technique that controls the exchange of data between main memory and an I/O module without continuous processor involvement, interrupting the processor only after an entire block has been transferred.

DMA Address Register

A register within the DMA module that stores the starting location in memory for reading or writing data.

DMA Data Count Register

A register within the DMA module that stores the specific number of words to be read or written during a transfer.

Single bus detached DMA

A DMA configuration where the DMA module and I/O modules share the same system bus, which can be inefficient as they must share bus access.

I/O Processor

An advanced I/O module that can execute an I/O program in main memory as directed by the CPU.

Buffering

A technique used to resolve inefficiencies by performing input transfers in advance of requests and output transfers after requests are made, reducing process wait times.

Block-oriented devices

Devices that store information in fixed-size blocks and transfer one block at a time, referencing data by block number (e.g., Disks and USB keys).

Stream-oriented devices

Devices that transfer data as a stream of bytes without a block structure, such as terminals, printers, and communications ports.

Single Buffer

An I/O buffering technique where the OS assigns a single buffer in system memory for reading ahead or storing data before it is written to a device.

Double Buffer

Also known as buffer swapping, this technique involves a process transferring data to or from one buffer while the operating system empties or fills the second buffer.

Circular Buffer

A collection of more than two buffers where each individual buffer acts as one unit in a circular structure to manage data flow.

Line-at-a-time fashion

A stream-oriented I/O method where user input or output is processed one line at a time, typically signaled by a carriage return.

Byte-at-a-time fashion

A stream-oriented I/O method used when each individual keystroke is significant, commonly following the producer/consumer model.

Double Buffering execution time

For block-oriented transfers, the execution time is defined by the formula $\max[C, T]$.