87
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/
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(
A
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)
O
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n
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u
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(
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g
g
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SMBus is also called I2C bus. It is a two-wire bus developed for component communication (especially for semiconductor IC). For
example, set clock of clock generator for jumper-less motherboard. The data transfer rate of SMBus is only 100Kbit/s, it allows one
host to communicate with CPU and many masters and slaves to send/receive message.
S
S
P
P
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D
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SPD is a small ROM or
EEPROM
device resided on the
DIMM
or
RIMM
. SPD stores memory module information such as DRAM
timing and chip parameters. SPD can be used by
BIOS
to decide best timing for this DIMM or RIMM.
U
U
l
l
t
t
r
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Ultra DMA (or, more accurately, Ultra DMA/33) is a protocol for transferring data between a hard disk drive through the computer’s
data path (or bus) to the computer’s random access memory (RAM). The Ultra DMA/33 protocol transfers data in burst mode at a
rate of 33.3MB/s, twice as fast as the previous
Direct Access Memory (DMA)
interface. Ultra DMA was developed as a proposed
industry standard by the Quantum corporation, makes of hard disk drives, and Intel, makes of chipset that support computer bus
technology. Ultra DMA support in your computer means that it will boot (start) and open new applications more quickly. It will help
users of graphic-intensive and applications that require large amounts of access to data on the hard disk drive. Ultra DMA uses
Cyclical Redundancy Checking (CRC), offering a new level of data protection. Ultra DMA uses the same 40-pin IDE interface cable
as PIO and DMA.
16.6MB/s x2 = 33MB/s
16.6MB/s x4 = 66MB/s
16.6MB/s x6 = 100MB/s
