Comparing the features of the DIrect Memory Access (DMA), interrupt systems and polling systems.

To see theise pages on Direct Memory Access (DMA) and Interrupt and Polling Systems

Direct Memory Access (DMA)
A diagram showing the position of the DMA in realtion to peripheral devices, the CPU and internal memory

  • Works in the background without CPU intervention
  • This speed up data transfer and CPU speed
  • The DMA is used for moving large files since it would take too much of CPU capacity

Interrrupt Systems
  • Interrupts take up time of the CPU
  • they work by asking for the use of the CPU by sending the interrupt to which the CPU responds
    • Note: In order to save time the CPU does not check if it has to respond
  • Interrups are used when a task has to be performed immediately

  • Polling requires the CPU to actively monitor the process
  • The major advantage is that the polling can be adjusted to the needs of the device
  • polling is a low level process since the perepherial device is not in need of a quick response

Edited by: Daniel Gillo
Last modification: 13th January 2011

  • Jones, Richard. Computer Science Java Enabled. Victoria: IBID Press, 2004.