73
M
M
X
X
4
4
6
6
U
U
2
2
-
-
G
G
N
N
/
/
M
M
X
X
4
4
6
6
-
-
5
5
3
3
3
3
G
G
N
N
O
O
n
n
l
l
i
i
n
n
e
e
M
M
a
a
n
n
u
u
a
a
l
l
A
A
G
G
P
P
(
(
A
A
c
c
c
c
e
e
l
l
e
e
r
r
a
a
t
t
e
e
d
d
G
G
r
r
a
a
p
p
h
h
i
i
c
c
P
P
o
o
r
r
t
t
)
)
The main function of AGP simply put is to tell monitor what screen information had to be shown, a visual transmission device
actually. With the rapid developing of AGP card, we can see that it had been developed from single colorful AGP card to 2D and 3D
graphic. AGP supports only memory read/write operation and single-master single-slave one-to-one only. Though AGP and PCI
share the same algorithm of 32-bit, its frequencies are 66MHz and 33MHz respectively. AGP interface had been developed from
2X to 8x.
1X AGP, data transfer rate is 66MHz x 4byte x 1 = 264MB/s
2X AGP, data transfer rate is 66MHz x 4byte x 2 = 528MB/s
4X AGP, data transfer rate is 66MHz x 4byte x 4 = 1056MB/s.
8X AGP, data transfer rate is 66MHz x 4byte x 8 = 2112MB/s.
A
A
M
M
R
R
(
(
A
A
u
u
d
d
i
i
o
o
/
/
M
M
o
o
d
d
e
e
m
m
R
R
i
i
s
s
e
e
r
r
)
)
The CODEC circuit of AC97 sound/modem solution can be put on motherboard or put on a riser card (AMR card) that connects to
motherboard through AMR connector.
A
A
T
T
A
A
(
(
A
A
T
T
A
A
t
t
t
t
a
a
c
c
h
h
m
m
e
e
n
n
t
t
)
)
Before talking about ATA (AT Attachment), we must understand
DMA
(Direct Memory Access), which allows devices to skip the
CPU devices and access memory directly. DMA specification could not only eliminate the workload of CPU, but also accelerate the
transmission of data. DMA begins with a data transfer rate of 16.6MB/Sec, but afterward developed to new data rate of 33.3MB/Sec,
which is twice the data rate and we called it
Ultra DMA
.
ATA
details power and data signals between the drive and integrated
