4. Type of case
ROM BIOS
Type of keyboard connector
Presence/absence of proprietary video and/or
proprietary local bus slots
Presence/absence of IDE adapters and SCSI controller
Presence/absence of COM ports, LPT ports, and
mouse port
Considerations When Selecting a
System Board
11. Main Components on a Motherboard
System clock
CPU and its
chip set
System bus
with expansion
slots
Jumpers and
DIP switches
ROM BIOS
CMOS configuration
chip and its battery
RAM
RAM cache (L2)
(optional)
Ports directly on the
board
Power supply
connections
12.
13. Random Access Memory (RAM).
RAM is used to hold programs while
they are being executed, and data
while it is being processed.
RAM is volatile, meaning that
information written to RAM will
disappear when the computer is
turned off.
RAM
14. RAM contents can be
accessed
in any (i.e. random) order.
By contrast, a sequential
memory device, such as
magnetic tape, forces the
computer to access data in
a fixed order because of the
mechanical movement of
the tape.
15. Two operations of RAM
Loading means copying data from the
secondary storage to the main memory
Saving means copying data from RAM
to the non-volatile secondary storage.
Types of RAM
SRAM
DRAM
SDRAM
DDR-RAM
16. Read-Only Memory can
be read but not changed.
It is non-volatile storage: it
remembers its contents even
when the 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.
ROM
17. CMOS Memory
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
updated/changed
CMOS memory requires (very
little) power to retain its
contents.
supplied by a battery on the
motherboard
the battery
18. The CPU
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
PowerPC chip
The CPU is also known as the processor or
microprocessor.
19. The CPU and RAM
The RAM
contains
data
and
programs
The data bus transports the
processed data to the RAM so
it can be stored, displayed, or
output.
The CPU
processes data.
22. The interface between peripheral devices
and the CPU.
A port is built on the motherboard while an
interface card is inserted into slots on the
motherboard.
Sometimes, an interface card may become a
built-in function on the motherboard.
Ports and Interface Cards