The Main Printed Circuit Board
Inside The PC That Contains and
Controls The Components That
Are Responsible For Processing
WHAT IS MOTHERBOARD?
The most important part of a PC is the
motherboard. It holds:
the processor chip
chips that handle input/output (I/O)
the expansion slots for connecting peripherals
Connects Directly or Indirectly to
Every Part of The PC
MOTHERBOARD IS MADE UP
A Chipset (known as the “glue logic”)
Some Code in ROM
Various Interconnections or Buses
CPU type and speed
Types of slots
Number of slots
Type of memory
Number of memory
Type of case
Plug & Play
Type of keyboard
A chip (microchip) is an integrated circuit - a
thin slice of silicon crystal packed with
microscopic circuit elements
e.g. wires, transistors,
MOVING DATAA data bus (a data path): connects the
parts of the motherboard.
Random Access Memory (RAM).
RAM is used to hold programs while they
are being executed, and data while it is be
RAM is volatile, meaning that information
written to RAM will disappear when the co
mputer is turned off.
RAM contents can be
in any (i.e. random) or
Virtual memory uses part of the
hard disk to simulate more memory
(RAM) than actually exists.
It allows a computer to run
more programs at the same
Virtual memory is
slower than RAM.
Read-Only Memory can
be read but not changed.
It is non-volatile storage: it
remembers its contents even when th
e power is turned off.
ROM chips are used to store the
instructions a computer needs during
start-up, called firmware.
Some kinds of ROM are PROM,
EPROM, EEPROM, and CD-ROM.
A computer needs a semi-permanent
way of keeping some start-up data
e.g. the current time, the no. of hard disks
the data may need to be
CMOS memory requires (very little)
power to retain its contents.
supplied by a battery on the motherboard
The Central Processing Unit (CPU)
is the chip on the motherboard that
acts as the "computer's brain"
it does calculations, and coordinates
the other motherboard components
CPU examples: the Pentium, the
The CPU is also known as the
processor or microprocessor.
Most expansion cards
contain a port.
A connector cable plugs
into the port, and leads
to a peripheral.
The expansion bus
transports data through
Common expansion cards:
graphics card (for connecting to a monitor)
network card (for transmitting data over a
sound card (for connecting to a microphone
Most PCs offer 4-8 expansion slots.
EXPANSION SLOT TYPES
There are several different types of
ISA: older technology, for modems and slow
PCI: for graphics, sound, video, modem or
AGP: for graphics cards
BOOTING A COMPUTER
Booting is the sequence of computer
operations from power-up until the system
is ready for use this includes hardware tes
ting, and loading the OS.
The computer checks the CMOS memory.
The computer loads configuration settings
from Config.sys or the Windows Registry.