.. _Device:

*************************************************
Device Management
*************************************************

.. .. seealso::

..   * `Video Lecture about Device and IO Management
     <https://online.ksu.edu/COMS/player/content/CMST_410/content/modules/Lectures/Device_IO/OS_Ch09_pt1.html?preview=1&ext=.html>`_

Hardware devices typically provide the ability to **input** data into the
computer or **output** data from the computer.  To simplify the ability to
support a variety of hardware devices, standardized 
application programming interfaces (API) are used.

* Application programs use the System Call API to request one of a finite set
  of preset I/O requests from the Operating System.  
  
* The Operating System uses algorithms for processing the request that are
  device independent.

* The Operating System uses another API to request data from the device driver.

* The device driver is third party software that knows how to interact with the
  specific device to perform the I/O.

* Sometimes we have a layering of device drivers where one device driver will
  call on another device driver to facilitate the I/O.  An example of this is
  when devices are connected to a USB port.  The driver for the device will
  make use of the USB device driver to facilitate passing data to and from the
  device.


**Contents:**

.. toctree::
   :maxdepth: 2

   drivers
   io_wait
   blocking
   top_bottom
   driver_implement
   buffers