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Ak Abd Harith bin Pg Abdul Rahim HND in Communications and Computer Systems
Engineering
CCSE | Intake 29 (2013) |Group 3
Computer
Hardware Second Assignment For Semester 1
Computer Systems and Applications
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PAGE 1
Different kinds of motherboards:
XT
AT – Advanced Technology
Baby-AT
ATX
Mini ATX
Micro ATX
Flex ATX Mini ITX
Nano ITX
Pico ITX
Mobile ITX
BTX
Micro BTX
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PAGE 2
Fig. 1.1 An example of an ATX motherboard
Fig. 1.2 An example of an AT motherboard
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PAGE 3
Difference between AT and ATX motherboard:
AT ATX
Older Newer (More commonly usednowadays)
13.8” × 12” (Wider in size) 12" x 9.6"
Not possible to customize portsin the back with backplates
Possible to customize the ports inthe back with backplates
Power switches connecteddirectly to the power supply
Power switch connected directly to the board
Number of pins on various connectors:
USB – 4 pins
IDE – 40 & 44 pins
SATA – 7 pins
ATX POWER CABLE – 24 pins, 20pins, 4 pins & 8 pins
PCI EXPRESS POWER CABLE – 6/8 pins
PARALLEL PORT – 25 pins
ETHERNET PORT – 8 pins
PC MOLEX CONNECTORS – 3 & 4 pin fan connector, 4 pins Floppy
power (mini-molex), 4 pin disk drive connector (Molex 8981)
PS/2 CONNECTOR – 6 pins
AT KEYBOARD CONNECTOR – 5 pins
VGA CONNECTOR – 15 pins
FIREWIRE CONNECTOR (IEEE 1394) – 4, 6 & 9 pins
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PAGE 4
DC Voltages from the DC power supply:
3.3 volts
5 volts
12 volts
Electrical problems when operating the PC:
Overheating
Electrostatic charges
Hardware failures
ESD, EMI and RFI:
ESD - Electrostatic discharge is the release of static electricity when
two objects come into contact.
EMI – ElectroMagnetic Interference, a naturally occurring phenomena
when the electromagnetic field of one device disrupts, impedes or
degrades the electromagnetic field of another device by coming into
proximity with it.
In computer technology, computer devices are susceptible to EMI
because electromagnetic fields are a byproduct of passing electricity through a wire. Data lines that have not been properly shielded are
susceptible to data corruption by EMI.
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PAGE 5
RFI – Radio Frequency Interference is when an electromagnetic
radiation which is emitted by electrical circuits carrying rapidly
changing signals, as a by-product of their normal operation, and which
causes unwanted signals (interference or noise) to be induced in othercircuits.
The most important means of reducing RFI are: use of bypass or
"decoupling" capacitors on each active device (connected across the
power supply, as close to the device as possible), risetime control of
high speed signals using series resistors and VCC filtering. Shielding is
usually a last resort after other techniques have failed because of theadded expense of RF gaskets and the like.
PC storages:
Hard disk driveCompact disk
Digital Versatile Disk
USB drive
Blu-ray disk
Floppy disk
Memory disk
Fig. 2.1 An example of a hard disk drive
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PAGE 6
RAM and pin numbers:RAM Slot Pins
DRAM (DynamicRAM)
SIMM 72
EDO DRAM (Extendeddata-out dynamic
RAM)
SIMM 72
RDRAM (RambusDRAM)
RIMM 184
SDRAM (SynchronousDRAM)
SODIMM
DIMM
144
168
DDR (Double datarate)
MicroDIMM
SODIMM
DIMM
172
200
184
DDR2
MicroDIMM
SODIMM
DIMM
214
200
240
DDR3
MicroDIMM
SODIMM
DIMM
214
204
240
GDDR3 DIMM 240
VRAM (VideoRAM) SIMM 72