7. Device Management

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:

• 7.1. Device Drivers
  • 7.1.1. The Device Driver Interface
  • 7.1.2. Device Driver Layers
  • 7.1.3. System Call Interface
  • 7.1.4. Example - UNIX Driver
• 7.2. Waiting for I/O
  • 7.2.1. Polling
  • 7.2.2. Interrupt Driven
• 7.3. Blocking and Nonblocking I/O
• 7.4. The Top and Bottom Halves of Drivers
• 7.5. Device Driver Implementation
  • 7.5.1. Device Independent Function Call
  • 7.5.2. Driver–Kernel Interface
  • 7.5.3. Reconfigurable Device Drivers
• 7.6. Using Buffers to Improve Performance