4 System Unit

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Discovering Computers 2009

Introduction to Information Systems

CHAPTER 4THE SYSTEM UNIT & MICROPROCESSORS


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The System Unit

What is the system unit?

Case that contains

system unit

electronic componentsof the computer used

Sometimes calledthe chassis

system unit

system unit

system unit

p. 4.04 Fig. 4-1 Next


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The System Unit

What are common components inside the system unit? Processor

power supply

Memory Adapter cards

processor

Modem card

Video cardports

memory

Network card Ports

sound card

Power supply

p. 4.03 Fig. 4-2 Next

modem card

network card


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The System Unit

What is the motherboard?

Main circuit

processor chip

adapter cards

board in systemunit

on a ns a ap er

cards, processor

chi s and

memory chips

memory chips

Also called

system board

motherboard

Expansion

slots for

adapter cards

p. 4.04 Fig. 4-3 Next


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The System Unit

What is a chip?dual inline

packages (DIP)

holds memory

chips

Small piece of semi-conducting

material on which integratedcircuits are etched

ntegrate c rcu ts conta nmany microscopic pathways

capable of carrying electrical

pin grid

array (PGA)

package

current

Chips are packaged so they can

o s processor

chips

p. 4.04 Fig. 4-4 Next


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Central Processing Unit: MicroprocessorsCentral Processing Unit: Microprocessors

What is a personal computer processor?

The sin le rocessor chi found in ersonal

computers Sometimes called a microprocessor

Processors identified by

Manufacturer

Model name ormodel number

Athlon

Celeron

Duron


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Microprocessors since the Year 2000

2000: Intel Pentium 4

2004: Intel Pentium 4 Extreme Edition (Dual Core)

2006: Intel Core 2 Duo (Dual Core)

2008: AMD Phenom X4 (Quad Core)

: n e e a em m on rans s ors


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Central Processing Unit: MicroprocessorsCentral Processing Unit: Microprocessors

Who are the personal computer processor manufacturers?Note: Apple Computer, Inc began using Intel microprocessors in 2005

Intel

AMD

PentiumII

with

(Intel-compatible)

Duron

Motorola

PowerPC AlphaCeleron

Xeon

AMD-K6

AthlonUsed inApples, Used in

an umDual Core

Quad Core

Used in PCs

and high-endservers

Click to view video

p. 4.9


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Microprocessorsicroprocessors

A microprocessor is a small calculating device usually used in our home PCswhich can easily fit in the palm of your hand. A microprocessor can do million ofcalculations in a blink of an eye.


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Devices which use microprocessorsDevices which use microprocessors


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Central Processing Unit

What is the central processing unit (CPU)?

rocessorrocessor

ControlControl

UnitUnit

ArithmeticArithmetic

Logic Unit (ALU)Logic Unit (ALU)

ArithmeticArithmeticLogic Unit (ALU)Logic Unit (ALU)

out basic instructionsthat operate a computer

ControlControlUnitUnit

InformationInformation

DataData


on ro un rec s an

coordinates operations in

computer

InputInput

DevicesDevices

OutputOutput

DevicesDevicesMemoryMemoryDataData InformationInformation

(ALU) performs

arithmetic, comparison,

InformationInformationDataData


Also called the processor

p. 4.05 Fig. 4-5 Next

StorageStorage

DevicesDevices


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What is a machine cycle?

Four o erations of the CPU com rise a machine c cle

Step 1. FetchObtain program instructionor data item from memory

Memory

.

DecodeTranslate

instruction into

commands

Step 4. StoreWrite result to memory

Control UnitALUStep 3. ExecuteCarry out command

p. 4.06 Fig. 4-6 Next


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What is a register?

Temporary high-speed storage area that holds

data and instructions [Data registers, Instructionregisters, Instruction Address registers,Address

Stores locationStores location

from where instructionfrom where instruction

was fetchedwas fetched

reg s ers, e c

StoresStores

instruction while it isinstruction while it is

being decodedbeing decoded

Stores dataStores data

while ALUwhile ALU

computes itcomputes it

Stores resultsStores resultsof calculationof calculation

p. 4.07 Next


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What is the system clock ? [Not the real-time clock!]

Controls timing of all computer operations

Generates regular electronic pulses, or ticks, that setoperating pace of components of system unit

Pace of systemPace of system

clock isclock is clock speedclock speed

Most clock speeds areMost clock speeds are Processor speed canProcessor speed can

is ais a

clock cycleclock cycle

in the gigahertz (GHz)in the gigahertz (GHz)

range (1 GHz = onerange (1 GHz = one

billion ticks of systembillion ticks of system

also be measured inalso be measured in

mmillions ofillions ofiinstructionsnstructions

pperer ssecondecond (MIPS)(MIPS)

(Some run at 3.8 GHz)(Some run at 3.8 GHz)

p. 4.07 Next


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What is a zero-insertion force (ZIF) socket?

Allows ou to install and remove chi s with no force

leverlever

Step 2.Step 1. Step 3.

Insert the chip.Lift the lever on the socket. Push the lever down.

p. 4.11 Fig. 4-10 Next


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What are heat sinks and heat pipes?

Heat sinkcomponent

with fins that coolsprocessor

heat sink fan

ea p peesma er

device for notebook

com uters

heat sink

p. 4.12 Fig. 4-11 Next


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Processor

What are heat sinks, heat pipes, and

li uid coolin ?

Heat sinkcomponentwith fins that cools

processor

Heat pipeesmaller

computers

Liquid coolinguses a

continuous flowof fluids to transfer heat away

p. 193 Fig. 4-9 Next


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What is a coprocessor?

Chip that assists processor inChip that assists processor in

performing specific tasksperforming specific tasks

One type is a floatingfloating--point coprocessorpoint coprocessor, alsoOne type is a floatingfloating--point coprocessorpoint coprocessor, also

p. 4.12 Next


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Data Representation

How do computers represent data?

Most com uters are di ital

Recognize only twodiscrete states: on or off

Use a binary system to

recognize two states se um er system w t

two unique digits: 0 and

1, called bits (short for

binary digits)

p. 4.13 Fig. 4-13 Next


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Data Representation

What is a byte?

Eight bits grouped together as a unit

Provides enough different combinations of 0s and 1sto represent 256 individual characters

Numbers

Uppercase

letters

Punctuation

marks

p. 4.13 Fig. 4-14 Next


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Data Representation

What are three popular coding systems to represent data?

ASCIIAmerican Standard Code for Information Interchan e

EBCDICExtended Binary Coded Decimal Interchange Code

Unicodecoding scheme capable of representing all

ASCII Symbol EBCDIC00110000 0 11110000

00110001 1 11110001

00110010 2 11110010

p. 4.14 Next


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Memory

What is memory? Electronic components that

Seat DCF2 Seat DCF3

store instructions, data, and

results

more chips on

motherboard oro er c rcu oar

Each byte stored

in unique location

called an address,similar to addresses

p. 4.15 Fig. 4-17 Next


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Memory

How is memory measured?

B the number of b tes available for stora e

Term Abbreviation Approximate Size

Kilobyte KB or K 1 thousand bytes

Megabyte MB 1 million bytes

Gigabyte GB 1 billion bytesera y e r on y es

p. 4.16 Fig. 4-18 Next


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Memory

What is CMOS?

Complementarymetal-oxide

Used in some

RAM chips, flash

memory chips, and

memory other types of

memory chips

Uses battery

power to retain

information when

Stores date,

time, and

com uters

other power isturned off

hardwareinformation

p. 200 Next


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Memory & Storage Terms

KILOBYTE (KB) 2^10 = 1024 BYTES ( thousand bytes) 10^3

MEGABYTE (MB) 2^20 = 1 048 576 BYTES (million b tes) 10^6

GIGABYTE (GB) 2^30 = 1,073,741,824 BYTES (billion bytes) 10^9

TERABYTE (TB) 2^40 = 1024 x 1,073,741,824 (trillion bytes) 10^12

PETABYTE (PB) 2^50 = million x billion bytes 10^15

EXABYTE (EB) 2^60 = billion x billion bytes 10^18

^ ^

YOTTABYTE (YB) 2^80 = trillion x trillion bytes 10^24

p. 4.16 Fig. 4-18 Next


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Memory

What is random access memory (RAM)?

Memory chips that can beMemory chips that can be

read from and writtenread from and written

to by processorto by processor

Also calledAlso called

main memorymain memory

Most RAM isMost RAM is

volatilevolatile, it is lost, it is lost

when computerswhen computers

storagestoragepower ispower is

turned offturned off

computer has, thecomputer has, thefaster it respondsfaster it responds

p. 4.17 Next


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Memory

How do program instructions transfer in and out of RAM?Step 1. When you start the computer, certainRAM

hard disk. The operating system displays the user

interface on the screen.

Operating systemOperating system

instructionsinstructions

Operating systemOperating system

interfaceinterface

Step 2. When you start a Web browser, theprograms instructions load into RAM from the

Web browserWeb browser

instructionsinstructions


windowwindow

hard disk. The Web browser window is displayedon the screen.

Step 3. When you start a word processingprogram, the programs instructions load into

Word processingWord processing

program instructionsprogram instructions

Word processingWord processing

program windowprogram window

RAM

rom e ar s . e wor process ngprogram, along with the Web Browser and certainoperating system instructions are in RAM. Theword processing program window is displayed onthe screen.

Step 4. When you quit a program, such as theWeb browser, its program instructions areremoved from RAM. The Web browser no longeris displayed on the screen.

p. 4.17 Fig. 4-19 Next

Web browser programWeb browser program

instructions areinstructions are

removed from RAMremoved from RAM


window no longer iswindow no longer is

displayed ondisplayed ondesktopdesktop


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Memory

What are two basic types of RAM chips?

Used forUsed for

specialspecial

applicationsapplications

MostMost

commoncommon

such assuch as

cachecache

typetype

(SRAM)(SRAM)

FasterFaster

variationsvariations

of DRAM areof DRAM are

Faster andFaster and

more reliablemore reliable

RAMRAMDynamicDynamic

RAMRAM

SDRAMSDRAM andandRDRAMRDRAM

anan

chipschips

p. 4.18 Next


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Memory

Where does memory reside?

Resides on small circuit

board called memory

module

emory s o s on

motherboard hold memory

modulesmemory chip memory slot

9 chips: parity check

8 chips: no parity check

p. 4.18 Fig. 4-20 Next


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Memory

How much RAM does an application require?

Software acka e

typically indicatesRAM requirements

System Requirements

Windows XP Home Edition/Professional Intel Pentium processor at 233MHZ or higher

AMD K6 (Athlon Duron Family processor at 233MHZ or higher

or op ma

performance, you

need more than

o

minimum specifications

p. 4.19 Fig. 4-21 Next

M T


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MemoryTypes

What is cache? [ cache means storage] Helps speed computer processes by storing frequently used

instructions and data

Also called memory cache

L2 cache slower but has larger capacity

L2 advanced transfer cache is faster,u rec y on processor c p

L3 cache is separate from processorchip on motherboard (L3 is only

on compu ers a use a vance

transfer cache)

p. 4.20 Fig. 4-23 Next


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Memory Types

What is cache? Helps speed computer processes by storing frequently used

instructions and data

Also called memory cache

L2 cache slower but has larger capacity

L2 advanced transfer cache is faster,u rec y on processor c p

L3 cache is separate from processorchip on motherboard (L3 is only

on compu ers a use a vance

transfer cache)

p. 201 Fig. 4-20 Next


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Most RAM must be recharged constantly

Volatile Memory loses contents when power is removed


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Memory: ROM (Read Only Memory)

What is read-only memory (ROM)?

emory c ps t at storeemory c ps t at store

permanent datapermanent dataand instructionsand instructions

Nonvolatile memoryNonvolatile memory, it is not, it is not

lost when computerslost when computerspower is turned offpower is turned off

Three types:Three types:

FirmwareFirmware

EEPROMEEPROM((eelectricallylectrically

eerasablerasable pprogrammablerogrammable

rreadead--oonlynly mmemory)emory)Manufactured withManufactured withpermanently writtenpermanently writtendata, instructions,data, instructions,or informationor information

containing microcodecontaining microcode

programmerprogrammercan erasecan erase

PROMPROM((pprogrammablerogrammable

rreadead--oonlynlymmemoremor

Blank ROMBlank ROMchip onto whichchip onto whicha programmera programmer

can write permanentlycan write permanently

p. 4.20 Next


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Expansion Slots and Adapter CardsWhat is an adapter card?

Enhances s stem unit or rovides connections to

external devices called peripherals

Also called an expansion card

p. 204 Fig. 4-24 Next

S d d


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Expansion Slots and Expansion Cards

What is an expansion slot?

An o enin , or socket,

on the motherboard

that can hold an

a ap er car

With Plug and Play,

the com uterautomatically

configures cards

an ot er ev cesas you install them

p. 4.23 Fig. 4-28 Next

E i Sl d E i C d


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Expansion Slots and Expansion Cards

What are PC cards and flash memory cards?

A PC card adds memor , sound,

modem, and other capabilities to

notebook computers

as memory car a ows

users to transfer data from

mobile devices to desktocomputers

Hot plugging allows you to insert

and remove cards while computeris running

p. 4.24 Fig. 4-294-30 Next


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P


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Ports

What are different types of connectors?

p. 4.26 Fig. 4-33 Next

S i l P t


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Serial Ports

What is a serial port?

Transmits one bit of data at a

time

Connects slow-speed devices,

suc as mouse, ey oar ,

modem

p. 4.27 Fig. 4-34 Next

P r ll l P rt


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Parallel Ports

What is a parallel port?

Connects devices that can

transfer more than one bit at

a time, such as a printer

p. 4.27 Fig. 4-35 Next

USB Ports


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USB Ports

What are USB ports?

USB (universal serial bus) port can connect

up to 127 different peripherals together

USB (universal serial bus) port can connect

up to 127 different peripherals together

Third USBThird USBPCs typically havePCs typically havedevice connects

to second USB

device, and so on

device connects

to second USB

device, and so on

ng e port can

be used to attach

multiple peripherals

ng e port can

be used to attach

multiple peripherals

two to four USB ports

on front or back of

the system unit

two to four USB ports

on front or back of

the system unit

Second USBdevice connects

to first USB

Second USBdevice connects

to first USBFirst USBFirst USB

device connects

to USB port

on computer

device connects

to USB port

on computerp. 4.28 Next

Special Purpose Ports


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Special Purpose Ports

What are special-purpose ports?

Allow users to attach specialized peripherals (digital video

cameras, color printers, scanners, and disk drives) or

transmit data to wireless devices

re re por

MIDI (Musical

Instrument DigitalInterface) port

SCSI (smallcom uter s stem

interface) port IrDA (Infrared Data

p. 4.28 Fig. 4-37 Next

BluetoothTM port

Buses (Speeds: 400 MHz to 1066 MHz)


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Buses (Speeds: 400 MHz to 1066 MHz)

What is a bus? Channel that allows devices

ns e computer to

communicate with each other System bus connects processor

and RAM

Bus width determines number

of bits transmitted at one time Word size is the number of

bits processor can interpretand execute at a given time

p. 4.30 Fig. 4-38 Next


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Expansion Buses


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Expansion Buses

What is an expansion bus?

Allows processor to communicate with peripherals

PC Card FireWire PCIAGPUSB

p. 212 Next

Firewire (IEEE 1394)Ports and Connectors


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Firewire (IEEE 1394)Ports and Connectors

What are FireWire ports?

Connects multiple types of devices that require

faster data transmission speeds

Allows you to connect up to 63 devices together

p. 209 Next

External & Internal Bays


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External & Internal Bays

What is a bay?

Open area inside

system unit used to

install additional

Drive bays typically

hold disk drives

p. 4.32 Fig. 4-40 Next

4 System Unit

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