Information Technology Reference
In-Depth Information
11.9 Exercises
11.9.1
Which bus is the AGP bus based on:
(a)
PCI
(b)
IDE
(c)
ISA
(d)
USB
11.9.2
How does AGP increase the data rate by x2 (and even x4):
(a)
Extra clock signals
(b)
Increased data bus size
(c)
Direct memory accesses
(d)
Increased address bus size
11.9.3
Which of the following is
not
an advantage of using the AGP bus:
(a)
Faster transfers between memory and the graphics devices
(b)
Increased usage of main memory (with reduced need for localized
memory)
(c)
Reduced requirement for interrupts
(d)
Increase throughput compared with the standard PCI bus
11.9.4
Which of the following identifies the address/data lines on the AGP bus:
(a)
HAD[31:0]
(b)
GAD[31:0]
(c)
AAD[31:0]
(d)
AD[31:0]
11.9.5
Explain the main objectives of the AGP bus and outline the advantages of moving
textural information into main memory.
11.9.6
Contrast the PCI and AGP busses and how AGP increases the data throughput.
Also discuss the extra signal lines used with AGP, and how they are used.
11.10 Notes from the author
So, what's the biggest weakness of the PC. In the past, it has probably been the graphics
facilities. This is mainly because the bus systems within the PC did not support large data
throughput (ISA/EISA is way too slow). The design of the graphics system also required that
the video card required to store all the data which was to be displayed on the screen. Thus
no matter the amount of memory on the system, it was still limited by the amount of memory
on the graphics card. AGP overcomes this by allowing graphical images to be stored in the
main memory and then transferred to the video displayed over a fast bus.
The data demand for graphical displays is almost unlimited, as the faster they can be
driven, the greater their application. The AGP bus is an excellent extension to the PCI bus,
and gives data throughput of over 500 MB/s, whereas standard PCI devices can typically
only be run at less than 100 MB/s. AGP is now a standard part of most PC motherboards,
and it is still to be seen if many systems will start to use this port.
.
