Information Technology Reference
In-Depth Information
TABLE 3.2
Peripheral Communication Design and Comparison
Purpose
Advantages
Disadvantages
Efficiency
Implementation
Interrupts
Lets the operating
system know that
the hardware is
ready to be serviced
The operating system
does not need to
waste time checking
the hardware
Can be complicated to
implement
Efficient since the
hardware notifies
the operating system
as soon as it's ready
Requires special
hardware that
supports interrupts
Polling
The operating system
checks to see
whether the
hardware is ready
Does not require
special hardware
Wastes CPU time checking
hardware that may not be
ready. Hardware must wait
for poll even if it's ready
Time is wasted when
poll is performed
and hardware is not
ready
Easy
DMA
The hardware writes
data directly to
memory
Does not need CPU; it
is freed up for task
execution
The operating system is not
notified when the hardware
is ready; the application
must check the memory
Efficient because it
does not require
CPU, but operating
system is not
notified
Requires special
hardware that
handles the DMA
transfer of data
 
Search WWH ::




Custom Search