secondary storage.pptx

8/15/2019 secondary storage.pptx

1/24

Computer Components

5-1


2/24

Motherboard

5-2


3/24

Von Nuemann Architecture• The parts are connected to one

another by a collection of wirescalled a bus

5-3

Figure 5.2 Data flow through a von Neumann architecture


4/24

Von Nuemann Architecture• The bus is !A"#$ by se%eral de%ices• This a&ects how data 'ows

• ANA()*+, – ho do you call most on your cell

phone. – ome de%ices communicate more than

others

5-/


5/24

%on Neumann Architecture

5-5Figure 5.1 The von Neumann architecture


6/24

Main Memory 0"AM

5-


7/24

"AM• Memory is a

collection ofcells

each with auni4ue physicaladdress

• !ow many databits.

• !ow manyaddress bits.

Page 122 5-8


8/24

hat is in a C 6..

5-7


9/24

C 6

C 6 Components• Arithmetic (o8ic 6nit• Control 6nit•

"e8isters

5-9

A(60does thewor:

"#*0holds data

C60The ;ossM#M)"+ pro8ra

m


10/24

Arithmetic


11/24

"e8isters• Contain the data that the C 6 is

processin8 ?at the moment@

• There is a set of re8isters

5-11


12/24

Control 6nit• Control unit controls the

instruction cycle

• "eads in a pro8ram oneinstruction at a time

• Tells the A(6 what to do

5-12


13/24

Control 6nit• There are two special re8isters in the

control unit

– The instruction register 0 " containsthe instruction that is bein8 e=ecuted

– The program counter 0 C containsthe address of the ne=t instruction to bee=ecuted

5-13


14/24

Memory and the Memoryyramid

5-1/

Capacity CostB

peed

Tape

Ma8netic $is:

Cache

Main "AM

lash "AM


15/24

rimary and econdarytora8e

• rimary tora8e – a:a ?Main Memory@ 0usually "AM – the ?wor:in8 memory@ of the C 6 – ast – !i8h D per byte

• econdary tora8e – where all the stu& that is not bein8 wor:ed on ?now@ is

stored 0usually $ E – low – (ow D per byte

5-15


16/24

rimary Memory - "AM• "AM stands for Random Access Memory

– Any location can be accessed 4uic:ly – ame amount of time to access any location

0a:a FrandomG• "AM is %olatile

– $ata is () T when the power is turned o& • rimary 0Main memory is

– Volatile – (imited – #=pensi%e

5-1


17/24

rimary %s econdary• Computers ha%e a ;A(ANC# of

rimary and econdary Memory

• Trade o&s, – peed – iHe – Cost

5-1I


18/24

econdary Memory• econdary memory is

– ;i8 – Cheap – lower than rimary Memory

• #=amples, – Ma8netic $is: – C$ "om – lash 0 olid tate $ri%es

5-17


19/24

Ma8netic Tape• The Jrst truly

mass au=iliarystora8e de%ice

was thema8netic tapedri%e

• Cassette Tapesare still used forlar8e databac:ups

Figure 5.4 A magnetic tape 5-1


20/24

Ma8netic $is:s• A read


21/24

Compact $is:s• A C$ dri%e uses a laser to read

information stored optically on aplastic dis:

• C$-")M is "ead-)nly Memory – Appro=imately I>>M;

• $V$ stands for $i8ital Video $is: – Appro=imately / *;

5-21


22/24


23/24


24/24

secondary storage.pptx

Documents

Transcript of secondary storage.pptx