G-2
Glossary
CMOS
(
c
omplementary
m
etal-
o
xide
s
emiconductor
)
CMOS is a widely used type of semiconductor, which features high speed and low power
consumption. PCs usually contain a small amount of battery-powered CMOS memory to
retain the date, time, and system setup parameters.
COM
In MS-DOS system, the name of a serial communications port. DOS supports four serial
ports. For example, if a modem is connected to one serial port and a serial mouse to another,
they are identified as COM1 and COM2.
DIMM
(
d
ual
i
n-line
m
emory
m
odule
)
A small circuit board that holds memory chips. A
SIMM
(
s
ingle
i
n-line
m
emory
m
odule)
has
a 32-bit path to the memory chips whereas a DIMM has 64-bit path.
DMA
(
d
irect
m
emory
a
ccess
)
A transfer mode between the main memory and the peripheral devices that without passing
through the CPU. Using the DMA controller, data is transferred much faster.
DRAM
(
D
ynamic
RAM
)
A most common type of computer memory. It usually uses one transistor and a capacitor to
represent a bit. As the development of technology, the memory type and specification used
in computer becomes variety, such as SDRAM, DDR SDRAM, and RDRAM. For further
instruction, please see the table below:
Dynamic RAM (DRAM) Memory Technologies
Type
FPM (60,70ns)
EDO (50,60,70ns)
SDRAM (66MHz)
SDRAM (100MHz)
SDRAM (133MHz)
RDRAM (Direct Rambus)
DDR SDRAM (100MHz)
DDR SDRAM (133MHz)
First Used
1990
1994
1996
1998
1999
1999
2000
2000
Clock Rate
25MHz
40MHz
66MHz
100MHz
133MHz
400MHz
100MHz
133MHz
Bus* Width
64 bits
64 bits
64 bits
64 bits
64 bits
16 bits
64 bits
64 bits
Bandwidth
200 MBps
320 MBps
528 MBps
800 MBps
1.1 GBps
1.6 GBps
1.6 GBps
2.1 GBps
Volts
5v
5v
3.3v
3.3v
3.3v
2.5v
3.3v
3.3v
Peak
* Memory channel width (64 bits started with 75MHz Pentium)
Source: Computer Desktop Encyclopedia
a PC chipset provides the electronic interfaces between all subsystems.
