Components of System Unit

In these slides, you learn about components of system units such as motherboard, chip, processor, registers, and pipelining.

1. Components
of
System Unit
1

2. The System Unit
•What is thesystem
unit?
Case that contains electronic
components of the computer used
to process data
Sometimes called
thechassis
2

3. The System Unit
•What are common components inside the
system unit?
Memory
Adaptercards
Sound card
Modem card
Video card
Network card
Ports
Drive bays
Powersupply
power supply
ports
drive bays
processor
memory
sound card
video card
modem card
network card
Processor
3

4. 4

5. The System Unit
•What is the
motherboard?
Main circuit
board in system
unit
Contains adapter
cards, processor
chips, and
memory chips
Also called
system board
processor chip
adapter cards
memory chips
memory slots
motherboard
Expansion
slots for
adapter cards
5

6. The Motherboard and CPU
•Themotherboardisthemain
circuitboard of a
microcomputer.Itcontains
thecentralprocessingunit
(CPU),theBasicInput/Output
System(BIOS),memory,
massstorageinterfaces,
serialandparallelports,
expansionslots,andallthe
controllersforstandard
peripheraldeviceslikethe
keyboard,diskdriveand
displayscreen.
6

7. The System Unit
•What is achip?
dual inline
packages (DIP)
holds memory
chips
pin grid
array (PGA)
package
holds processor
chips
Small piece of semi-conducting
material on which integrated
circuits are etched
Integrated circuits contain
many microscopic pathways
capable of carrying electrical
current
Chips are packaged so they can
be attached to a circuit board
7

8. Processor
Control
Unit
Arithmetic
Logic Unit (ALU)
Arithmetic
Logic Unit (ALU)
Processor
What is thecentral processing unit (CPU)?
Input
Devices
Storage
Devices
Output
Devices
Interprets and carries
out basic instructions
that operate a computer
MemoryData Information
Instructions
Data
Information
Instructions
Data
Information
Control
Unit
Control unitdirects and
coordinates operations in
computer
Arithmetic logic unit
(ALU)performs
arithmetic, comparison,
and logical operations
Also called theprocessor
8

9. Processing Sequence
TwocrucialaspectsarerelatedwithProcessors
&Processing
1. Machine Cycles
•Control unit and memory working together to perform all
instructions on computer
•Two cycles
–InstructionCycle(Fetchinstructionandtranslatethem)
–Fetch
–Decode
–ExecutionCycle(ProcessandProduce(store)results)
–Execute
–Store
9

10. Processing Sequence
2. Registers
•Toexecutemachinecycles,thecontrolunitneedstemporary
storagespacescalled“Registers”
•PartofProcessornotStorageorMemorydevices
•Thesearefasterthanthemainmemory
•Theirpurposeistoholdmostfrequentinstructionscarriedout
byprocessorsandthereforetheyeventuallyspeedsusthe
executionprocess
10

11. Stores location
from where instruction
was fetched
Processor
Stores
instruction while it is
being decoded
•What is aregister?
Stores data
while ALU
computes it
Stores results
of calculation
Temporary high-speed storage area that holds
data and instructions
11

12. 12

13. Processor
Control Unit
Memory
ALU
Processor
What is amachine cycle?
Step 1. Fetch
Obtain program instruction
or data item from memory
Step 2.
Decode
Translate
instruction into
commands
Step 4. Store
Write result to memory
Step 3. Execute
Carry out command
Four operations of the CPU comprise a machine cycle
13

14. 14

15. Processor
•What ispipelining?
CPU begins fetching second instruction before
completing machine cycle for first instruction
Results in faster processing
15

16. Processor
What is thesystem clock?
FLOPS
Floating Point Operations
per second
Pace of system
clock is clock speed
Most clock speeds are
in the gigahertz (GHz)
range (1 GHz = one
billion ticks of system
clock per second)
Processor speed can
also be measured in
millions of instructions
per second (MIPS)
Controlstimingofallcomputeroperations
Generatesregularelectronicpulses,orticks,thatset
operatingpaceofcomponentsofsystemunit
Eachtickisaclockcycle(milliontobilliontimesin1sec)
16

17. Chip-for chip upgrade
replace the chip
Processor
•What are the types of processor
upgrades?
Piggyback upgrade
stack new chip on top of old one
Daughterboard upgrade
chip is on adapter card that plugs into motherboard
17

18. Processor
What is azero-insertion force (ZIF)socket?
Step 2.
Insert the chip.
Step 1.
Lift the lever on the socket.
lever
Step 3.
Push the lever down.
lever
Allows you to install and remove chips with no force
18

19. Processor
What isparallel
processing?
Control Processor
Processor 1
Memory
Processor 2
Memory
Processor 3
Memory
Processor 4
Memory
Results combined
Using multiple
processors
simultaneouslyto
executeaprogram
faster
Requiresspecial
softwaretodivide
problemandbring
resultstogether
SIMDv/sMIMD
19

20. Data Representation
How do computers represent data?
Recognize only two
discrete states: on or off
Use a binary systemto
recognize two states
Use Number system with
two unique digits: 0 and
1, called bits(short for
binary digits)
Most computers aredigital
20

21. Data Representation
What is abyte?
Eight bits grouped together as a unit
Provides enough different combinations of 0s and 1s
to represent 256 individual characters
Numbers
Uppercase
and lowercase
letters
Punctuation
marks
Encoding
21

22. Data Representation
What are three popular coding systems to represent
data?
ASCII—AmericanStandardCodeforInformationInterchange
EBCDIC—ExtendedBinaryCoded DecimalInterchangeCode
Unicode—coding scheme capable of representing all
world’s languages
ASCII Symbol EBCDIC
00110000 0 11110000
00110001 1 11110001
00110010 2 11110010
00110011 3 11110011
22

23. Data Representation
How is a letter converted to binary form and
back?
Step 1.
The user presses
the capital letter D
(shift+D key) on
the keyboard.
Step 2.
An electronic signal for the
capital letter Dis sent to the
system unit.
Step 3.
The signal for the capital letter D
is converted to its ASCII binary
code (01000100) and is stored in
memory for processing.
Step 4.
After processing, the binary
code for the capital letter Dis
converted to an image, and
displayed on the output device.
23

24. Memory
What ismemory?
Electronic components that
store instructions, data, and
results
Consists of one or
more chips on
motherboard or
other circuit board
Each byte stored
in unique location
called anaddress,
similar to seats
on a passenger train
Seat #2B4Seat #2B3
24

25. Memory
How is memory measured?
Term AbbreviationApproximate Size
Kilobyte KB or K 1 thousand bytes
Megabyte MB 1 million bytes
Gigabyte GB 1 billion bytes
Terabyte TB 1 trillion bytes
By number of bytes available for storage
25

26. Memory
What israndom access memory (RAM)?
The more RAM a
computer has, the
faster it responds
Also called
main memory
or primary
storage
Most RAM is
volatile, it is lost
when computer’s
power is
turned off
Memory chips that can be
read from and written
to by processor
26

27. Memory
How do program instructions transfer in and out of
RAM?
Step 1.When you start the computer, certain
operating system files are loaded into RAM from
the hard disk. The operating system displays the
user interface on the screen.
Operating system
instructions
Web browser
instructions
Word processing
program instructions
Operating system
interface
Web browser
window
Word processing
program window
RAM
RAM
Web browser program
instructions are
removed from RAM
Web browser
window no longer is
displayed on
desktop
Step 2.When you start a Web browser, the
program’s instructions are loaded into RAM from
the hard disk. The Web browser window is
displayed on the screen.
Step 3.When you start a word processing
program, the program’s instructions are loaded
into RAM from the hard disk. The word
processing program, along with the Web Browser
and certain operating system instructions are in
RAM. The word processing program window is
displayed on the screen.
Step 4.When you quit a program, such as the
Web browser, its program instructions are
removed from RAM. The Web browser no longer
is displayed on the screen.
27

28. Faster
variations
of DRAM are
SDRAMand
RDRAM
Used for
special
applications
such as
cache
Most
common
type
Faster and
more reliable
than DRAM
chips
Memory
What are two basic types of RAM chips?
Dynamic
RAM
(DRAM)
•Future: Magnetoresistive RAM (MRAM)
Static
RAM
(SRAM)
28

29. Memory
•Where does memory
reside?
Resides on small circuit
board calledmemory
module
Memory slotson
motherboard hold memory
modules
memory chip memory slot
dual inline memory module
29

30. Memory
How much RAM does an application require?
Software package
typically indicates
RAM requirements
For optimal
performance, you
need more than
minimum specifications
System Requirements
Windows
®
XP Home Edition/Professional
•Intel Pentium processor at 233MHZ or higher
•AMD K6 (Athlon Duron Family processor at 233MHZ or higher
•64 MB of RAM
30

31. Memory
How much RAM do you need?
Depends on type of applications you intend to run
on your computer
RAM
Use
128 to 256 MB 256 to 1 GB 1 GB and up
•Home and business
users managing
personal finance
•Using standard
application software
such as word processing
•Using educational
or entertainment
CD-ROMs
•Communicating with
others on the Web
•Users requiring more advanced
multimedia capabilities
•Running number-intensive
accounting, financial, or
spreadsheet programs
•Using voice recognition
•Working with videos, music, and
digital imaging
•Creating Web sites
•Participating in video conferences
•Playing Internet games
•Power users creating
professional Web sites
•Running sophisticated
CAD, 3D design, or
other graphics-intensive
software
31

32. Memory
What iscache?
L1cachebuiltintoprocessor
L2cacheslowerbuthaslargercapacity
L2advancedtransfercacheisfaster,
builtdirectlyonprocessorchip
L3cacheisseparatefromprocessor
chiponmotherboard(L3isonly
oncomputersthatuseL2advanced
transfercache)
256KBofL2forPersonalcomputers
2MBofL2forServers
Helps speed computer processes by storing frequently used
instructions and data
Also calledmemory cache
32

33. Memory
What isread-only memory (ROM)?
Memory chips that store
permanent data
and instructions
Nonvolatile memory, it is not
lost when computer’s
power is turned off
Three types:
Firmware
Manufactured with
permanently written
data, instructions,
or information
EEPROM
(electrically
erasable programmable
read-only memory)—
Type of PROM
containing microcode
programmer
can erase
PROM
(programmable
read-only
memory)—
Blank ROM
chip onto which
a programmer
can write permanently 33

34. Memory
What isflash memory?
Step 1.
Purchase and download MP3 music tracks
from a Web site. With one end of a special
cable connected to the system unit, connect
the other end into the MP3 player.
Step 2.
Instruct the computer to copy the MP3 music track
to the flash memory chip in the MP3 player.
Step 3.
Plug the headphones into the MP3
player, push a button on the MP3
player, and listen to the music
through the headphones.
MP3 Player
Flash memory chip
Flash memory card
From computer
To headphones
Nonvolatile memory that can be erased electronically and
reprogrammed
Used with PDAs, digital cameras, digital cellular phones, music players,
digital voice recorders, printers, Internet receivers, and pagers
34

35. Memory
What isCMOS?
Uses battery
power to retain
information when
other power is
turned off
Stores date,
time, and
computer’s
startup
information
Complementary
metal-oxide
semiconductor
memory
Used in some
RAM chips, flash
memory chips, and
other types of
memory chips
35

36. Memory
What isaccess time?
Amount of time it takes processor
to read data from memory
Measured in nanoseconds (ns),
one billionth of a second
It takes 1/10 of a second to blink
your eye; a computer can perform
up to 10 million operations in same amount of
time
Term Speed
Millisecond One-thousandth of a second
Microsecond One-millionth of a second
Nanosecond One-billionth of a second
Picosecond One-trillionth of a second
36

37. Expansion Slots and Adapter Cards
What is anadapter card?
Types of Adapter Cards
Enhances system unit or
provides connections to
external devices called
peripherals
Also called anexpansion card
37

38. VGA\Sound Card
38

39. Expansion Slots and Adapter Cards
What is anexpansion slot?
An opening, or socket,
on the motherboard
that can hold an
adapter card
WithPlug and Play,
the computer
automatically
configures cards
and other devices
as you install them
39

40. PCMCIA (PC Card)
•Personal Computer Memory Card
International Association
•Found on notebook computers
40

41. Expansion Slots and Adapter Cards
What arePC cards andflash memory cards?
APC cardadds memory, storage,
sound, fax/modem,
communications, and other
capabilities to notebook computers
Aflash memory cardallows users
to transfer data from mobile
devices to desktop computers
Hot pluggingallows you to insert
and remove cards while computer
is running
41

42. Ports and Connectors
What areportsandconnectors?
Portconnects external devices to system unit
Connector joins cable to peripheral
Available in one of two genders: maleand female
42

43. Ports and Connectors
What are different types of connectors?
43

44. Ports and Connectors
What is aserial port?
Transmits one bit of data at a
time
Connects slow-speed devices,
such as mouse, keyboard,
modem
44

45. 45

46. Ports and Connectors
What is aparallel port?
Connects devices that can
transfer more than one bit at
a time, such as a printer
46

47. Third USB
device connects
to second USB
device, and so on
Second USB
device connects
to first USB
device
First USB
device connects
to USB port
on computer
Single USB port can
be used to attach
multiple peripherals
in a daisy chain
PCs typically have
four to eight USB ports
on front or back of
the system unit
Ports and Connectors
What areUSB ports?
USB(universal serial bus) portcan connect
up to 127 different peripherals together
with a single connector type
47

48. Ports and Connectors
What arespecial-purpose ports?
FireWire port
MIDI (Musical
Instrument Digital
Interface) port
SCSI (small
computer system
interface) port
IrDA (Infrared Data
Association) port
Bluetooth port
Allow users to attach specialized peripherals (digital video
cameras, color printers, scanners, and disk drives) or
transmit data to wireless devices
48

49. Buses
What is abus?
Channel that allows devices
inside computer to
communicate with each other
System bus connects processor
and RAM
Bus width determines number
of bits transmitted at one time
Word sizeis the number of
bits processor can interpret
and execute at a given time
49

50. Buses
What is anexpansion bus?
Allows processor to communicate with peripherals
50

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