Programmed input/output (PIO) is a method of transferring data between the CPU and a peripheral such as a network adapter or an ATA storage device.
In general, programmed I/O happens when software running on the CPU uses instructions that access I/O address space to perform data transfers to or from an I/O device. This is in contrast to Direct Memory Access (DMA) transfers.
The best known example of a PC device that uses programmed I/O is the ATA interface; however, this interface can also be operated in any of several DMA modes. Many older devices in a PC also use PIO, including legacy serial ports, legacy parallel ports when not in ECP mode, the PS/2 keyboard and mouse ports, legacy MIDI and joystick ports, the interval timer, and older network interfaces.
Read more about Programmed Input/output: PIO Mode in The ATA Interface
Famous quotes containing the words programmed, input and/or output:
“Ideally, advertising aims at the goal of a programmed harmony among all human impulses and aspirations and endeavors. Using handicraft methods, it stretches out toward the ultimate electronic goal of a collective consciousness.”
—Marshall McLuhan (1911–1980)
“Celebrity is a mask that eats into the face. As soon as one is aware of being “somebody,” to be watched and listened to with extra interest, input ceases, and the performer goes blind and deaf in his overanimation. One can either see or be seen.”
—John Updike (b. 1932)
“Lizzie Borden took an axe
And gave her mother forty whacks;
When she saw what she had done,
She gave her father forty-one.”
—Anonymous. Late 19th century ballad.
The quatrain refers to the famous case of Lizzie Borden, tried for the murder of her father and stepmother on Aug. 4, 1892, in Fall River, Massachusetts. Though she was found innocent, there were many who contested the verdict, occasioning a prodigious output of articles and books, including, most recently, Frank Spiering’s Lizzie (1985)