Tải bản đầy đủ - 0 (trang)
Chapter 2.  Portable PC Overview: Types and Features

Chapter 2.  Portable PC Overview: Types and Features

Tải bản đầy đủ - 0trang

TypesandClassesofPortableComputers

AswesawinChapter1,"PortableSystemsBackground,"over

theyearstherehavebeenseveralclassesofportable

computers,mainlydefinedbytheirformfactorand/orsize.This

sectionexaminesthedifferentclassesanddescribestheir

distinctivefeatures.

Theevolutionofportablesoverthepast20yearsshowsa

continualtrendinminiaturization.Whilethegeneralappearance

ofdesktopcomputershasnotsubstantiallychangedmuchsince

1985,theportablecomputerindustryhasspawnedseveralnew

classesofcomputers.Ingeneral,eachnewclassissmallerthan

thepreviousone.Theendresultisthatcomputerswithas

muchpowerasfull-sizeddesktopsystemscannowfitinto

handheldornotebook-sizedportables.

Atleastsevendifferentcategoriesofportablecomputershave

appearedonthemarket.Today,whilethereareindividualor

nichemarketexceptions,onlyfourmaincategoriesofPCcompatibleportablecomputersremainpopular:

Laptops/notebooks

Subnotebooks/ultraportables/ultralights

Tablets

Handhelds/palmtops

Ingeneral,asnew,smallerclassesappear,theolderandlarger

classesbecomeextinct.Thelaptop/notebookcategory,

however,hasnotbeenreplacedbyasmallercategoryand

insteadhasprovedsopowerfulandusefulthatitcontinuesto



bethemostpopularclassbyfarintheportablecomputer

industry.Thepoweroflaptopshasincreasedsomuchthat

manyusersareusingthemtoreplacetheirdesktops.Infact,

salesoflaptopsintheUnitedStateshaveexceededthatof

desktopsduringsomemonths.

Notethatdistinctionbetweentabletsandlaptops/notebookscan

beafuzzyone.Theoptionsavailableonsomesystemscause

particularmodelstoridethecuspoftwocategories.

Specifically,atabletcomputerwithanoptionalkeyboardcould

passasalaptop.Likewise,alaptopwithaflip-downtouchsensitivescreencouldbelabeledatablet.



LaptopsVersusNotebooks

Thedividinglinebetweenwhatwemightcallalaptopor

notebooksystemwasalwayssomewhatpoorlydefined,andin

facttodaythetermsarecompletelysynonymous.Whilethe

marketingdepartmentsinthecomputermanufacturershave

overwhelminglydecidedtocallalloftheirlaptopsnotebooks,

mostpeoplecontinuetousethemorereadilyunderstoodterm

laptopinstead.

Thedefinitionofalaptopcomputerisfairlysimple,alaptopis

anyportablecomputerfeaturingaclamshelldesign(wherethe

screenandkeyboardarehingedtogether),whichisalsosmall

andlightenoughthatitiscapableofbeingusedonone'slap.

Tothatdefinition,mostpeoplewouldaddtherequirementthat

thesystemshouldbecapableofrunningoninternalbatteries.

Thedefinitionofanotebookcomputerisunfortunatelymuch

lessclear.Originally,notebookcomputerswerejustthat,

computersthesizeofapapernotebook.Inotherwords,they

hadtobeabout8.5incheswideby11inchestall.Theyalsohad

afixeddisplay,whichmeansthesystemdidnotfeaturea

hingedclamshelldesignlikealaptop.Eventually,themarketing



departmentsofthevariouscomputercompaniesbeganusing

thetermnotebooktoapplytonotebook-sizedlaptops,meaning

systemsthatincorporatedthehingedclamshelldesign.

Eventually,theybeganusingthetermnotebookonsystems

thatwerelargerthanatruenotebook,buthavingaweight

belowsomearbitraryfigurelikesixpounds.Finally,allsizeand

weightdistinctionsweredropped,andthemarketerssimply

begantousethetermnotebooktodescribealloftheirlaptops.

Perhapstheythoughtthatcallingthemnotebookswassexier

thanlaptopsandsomehowimpliedthatthesystemswere

smallerandlighterthantheyreallywere?Ifounditinteresting

tonotethattheengineersandsystemdesignerscontinuedto

usethemoreaccurateanddescriptivetermlaptopstodescribe

theverysamesystemsthatthemarketershadstartedcalling

notebooks.Similarly,Ifoundthatmostpeople(myselfincluded)

alsocontinuetorefertothesesystemsgenericallyaslaptops.

Intheend,rememberthattherearenoofficialstandards

governingtheuseoftheseterms,andthattheyhavenow

becomecompletelyinterchangeable.Forthesakeofclarityand

understanding,throughoutthisbookIprefertousetheterm

laptopovernotebook,eventhoughthetwotermshavenow

becomecompletelysynonymousandinterchangeable.

Inanycase,today'slaptopshavebecomehigh-endmachines,

offeringfeaturesandperformancecomparabletoadesktop

system.Comparethattotheoriginalgenerationoflaptop

systems,whichnormallydidn'tevenhaveaharddrive.Indeed,

manyhigh-performancelaptopsarenowbeingissuedtousers

astheirsolecomputer,eveniftheironlyformoftravelistogo

fromhometotheofficeandback.Active-matrixdisplaysas

largeas17inches,upto2GBormoreRAM,andharddrivesof

upto160GBormoreinsizeareallbutubiquitous,withvirtually

allsystemsnowcarryingfastDVD+/-RWorCD-RWdrives,

onboardspeakers,andconnectivityoptionsthatenabletheuse

ofanexternaldisplay,high-speedstorage,andasurround

soundsystems.MostmodelsnowincludewirelessWi-Fi



networkcapabilitiesasstandardequipmentaswell.



Subnotebooks:TheEndofaTrend?

Theevolutionoflaptopshasfollowedaninterestingpath.Asthe

internalcomponentsoflaptopscontinuedtoshrinkinsize,of

course,sodidthesizeoflaptopsthemselves.

Eventually,thesizesshrunktoaweightoflessthan3pounds,

andthusanewcategorywasbornthesubnotebook.Butasmall

sizemeantasmallkeyboardandscreen,whichfurthermeant

thatthesubnotebookcouldbedifficulttouse.Despitesome

initialexcitementforthesesystems,theyfailedtoattracta

significantfollowing,andthecategorywassoonabandoned.At

longlast,portablecomputershadbecomesosmallthatsomeof

themwerenowtoosmall.

Nevertheless,theideaofahighlyportablelaptopwastoogood

toletdie.Ascomponentscontinuedtodecreaseinsize,itsoon

becamepossibletodesignalaptopthatwasbothlightweight

andreasonablypowerful.Butinsteadofadoptingthetainted

nameofsubnotebook,thesesystemswerenowgiventhenew

nameofultralight,acategorythatwillbediscussedinmore

detaillaterinthischapter.



TheManyTypesofLaptops/Notebooks

Aslaptopsandnotebookcomputersbecameincreasingly

popular,manufacturersbegantosegmentthemarket.Aswith

mostproducts,oneoftheprimarywaystosegmentthemarket

wasbyprice.Mostmanufacturersthusbeganofferingthree

linesoflaptopsaccordingtoprice:high-end,medium,and

bargain-basementorvalue.



Anotherwaytosegmenttheportablemarketwasintermsof

sizeandweight.Inmanycases,thesmallestandlightestlaptop

wasalsothemostexpensivebecauseitwasusingthelatest

components.Butoftenusersactuallypreferredheavier

systems.

Inthepastfewyears,aninterestingreverseevolutionbeganto

occur.Whilesomelaptopsbecamesmaller,otherstookamuch

differentcourse.AsLCDdisplayscreensgrewinsizefrom10.5

inchesto12.1,14.1,15,andeven17inchesandbeyond,a

classoflaptopshadtogrowinsizetoaccommodatethem.But

whilethefootprintofthelaptopsincreased,theirprofilehas

remainedrelativelythinusually1.5inchesorless.Mostusers

don'tseemtomindbecausealarge,thinlaptopismucheasier

tostuffintoabriefcasethanasmall,thickone.

Today,mostmanufacturerssegmentthemarketintouptofive

classes:desktopreplacement/gaminglaptops,mainstream

laptops,valuelaptops,thin&lightlaptops,andultralight

laptops.Somemightcombinethemainstreamandvalue

systemsintoasinglecategory,orlikewisecombinethethin&

lightandultralightintoasinglecategoryaswell.Asmallgroup

ofcompaniesspecializeinanadditionalclass:ruggedized

laptops.Table2.1comparesthebasicdimensionsandcosts

associatedwiththemostpopulartypesoflaptops.

Table2.1.TypicalCharacteristicsandPriceRangesfor

VariousTypesofLaptops

Thickness

(in.)



DisplaySize

(in.)



PriceRange



Desktop

6.08.0

replacement



1.52.0



1517



$1,000$4,000



Mainstream



6.08.0



1.52.0



1415



$1,000$2,500



Value



6.08.0



1.52.0



1415



$500$1,500



LaptopType



Weight

(lbs.)



Thin&light



4.55.5



1.01.5



12



$1,000$3,000



Ultralight



3.04.0



0.81.2



710



$1,000$3,000



Table2.2listthetypicalprocessors,maximummemory,and

maximumharddrivecapacitiesfoundinthevarioustypesof

laptops.

Table2.2.TypicalProcessors,MaximumMemory,and

MaximumHardDriveCapacitiesAvailableforthe

DifferentLaptopTypes

LaptopType



Desktop

replacement











Mainstream













Value



Typical

Processors



Maximum

Memory(GB)



MaximumHard

DriveSize(GB)



Pentium4



4



160



























2



120











































2



100



PentiumM

Athlon64

Turion

Pentium4

PentiumM

CeleronM

Athlon64

Turion

Sempron

Pentium4

















Thin&light









Ultralight











PentiumM

CeleronM

Celeron

Athlon64

Turion

Sempron

PentiumM

CeleronM

Turion

Sempron

PentiumM

CeleronM

Turion

Sempron



















































2



80



























1



60



























Thevariouslaptopformfactorsaredescribedinmoredetailin

thefollowingsections.Notethatthesedesignationscanbe

somewhatvague,andthemarketingdepartmentsinmost

companiesliketocomeupwiththeirowntermsforwhatthey

thinkaparticularsystemmightconformto.



DesktopReplacements

Desktopreplacementsaretheheavy-weightdivisionofthe

laptopfamily.Laptopsofthisclassareverysimilarinsizeand

weighttotheoriginallaptops.Theytypicallyweighbetween7

and12poundsormoreandareusuallylargeenoughto

accommodatethelargestlaptopdisplaysavailable,now1517

inchesmeasureddiagonally.

Asthenameimplies,thedesktop-replacementsystemis

designedtohavemostofthepowerandfeaturesofatypical

desktopcomputer.Thiseliminatestheneedforausertohave

bothadesktopandportable,whichsavesquiteabitofmoney.

Theselaptopsgenerallyhavetwoorthreedata-storagedrives:

Alargeharddriveandanopticaldriveofsometype(usuallya

DVDdriveoracombinationDVD/CD-RWdrive)areusually

includedasstandard;plusinsomecasesanoptionalthirddrive

baymightbeavailableaswell.Becauseallthesedrivesemploy

rotatingstoragemedia,theyarefrequentlyreferredtoas

spindles.Thus,mostdesktopreplacementlaptopshave

historicallybeenreferredtoastwo-orthree-spindlesystems.

Note,however,thatbecauseofthedecreasinguseoffloppy

disks,manyvendorsarenolongerbundlingfloppydrivesas

standardequipmentandonlyofferthemas$50externalUSB

attachedoptions.This,combinedwiththeemphasisonreducing

size,weight,andpowerconsumption,hasalsocausedvirtually

allthree-spindledesignstobediscontinued.Assuch,most

moderndesktop-replacementlaptopsarenowtwo-spindle

designs,withtheseconddrivecontainedinaswappablemedia

baywithoptionalopticaldrivesorharddrivecarriersavailable

toplugin.

Desktop-replacementlaptopseithercomestandardwithtop-ofthe-linecomponentsorhavethemavailableasoptions.This

meansthefastestmobileprocessors,thelargestamountsof

memoryandharddrivestorage,andthebestmobilevideo



accelerators.Table2.2showshowthecomponentsinthese

laptopscomparewiththoseinothercategories.

Thesesystemsgenerallyde-emphasizebatterylifeandpowerconservingtechnologyinfavorofdesktoptypeprocessorsand

videocomponents,makingthemmoresuitableforgamingand

multimediaapplications.Manydesktopreplacementsarebeing

positionedinthemarketasgamingormultimediasystems

suitablefordeliveringpresentationsontheroad.Becauseof

theirgreaterweight,theselaptopsleavethedeskonlyinthe

companyofsalespeopleandothertravelerswhoabsolutely

requirethefeaturestheyprovide.

Tousethemasadesktopreplacement,youcanequipmany

laptopswithadockingstation(oralessexpensiveport

replicator)thatfunctionsastheuser's"homebase,"enabling

connectiontoanetworkandtheuseofafull-sizemonitorand

keyboard.Forsomeonewhotravelsfrequently,this

arrangementoftenworksbetterthanseparatedesktopand

portablesystems,onwhichdatamustcontinuallybekeptin

sync.

Allthispowerdoesnotcomecheap.Thedesktop-replacement

laptopsaretypicallyamongthemostexpensivelaptops

available.Pricesnowrangefrom$1,000to$4,000ormore.An

equivalentdesktopcanoftenbepurchasedforhalfthisamount,

butkeepinmindthatdesktoppricesdonotusuallyincludea

largeflat-paneldisplay.



MainstreamLaptops

Peoplewhobuylargenumbersoflaptopsareinterestedinthe

bestcombinationoffunctionalityandprice.Aswiththethin&

lightlaptops,thecomponentryofamainstreamlaptopdoesnot

havetobeofthelatestandgreatestvintage,butneitherdoes

thelaptophavetobeverylight.Themaingoalislowprice.The



laptopshavetoberelativelypowerful,butanycomponentthat

isnotabsolutelyessentialisleftout.

Tocutcosts,mainstreamlaptopsuseaverage-sizedisplays

(today,14or15inchesindiagonal),lowercapacityharddrives,

andincludeanaverageamountofRAM.Floppydriveshave

universallybeeneliminatedfromvirtuallyallmodernlaptops;

however,mostmanufacturersenableuserstoattach(and

optionallybootfrom)anexternalUSBfloppydriveifnecessary.

Mainstreamlaptopsaremidwayinsizeandweightbetweenthe

thin&lightanddesktop-replacementlaptops.Pricescanrange

from$1,000to$2,500ormore.Becausetheyaretwo-spindle

systemsanddonotneedspaceforalargedisplay,these

laptopscanbesignificantlysmallerandlighterthanthe

desktop-replacementsystems.



ValueLaptops

Valuelaptopsaredesignedtoappealtopeoplewhorequireonly

aminimumlevelofperformance.Theselaptopsaredesignedto

sellatlowprices.Tocreatetheirvalueline,some

manufacturerssimplytakeavariationoftheirexisting

mainstreamlaptopsandconfigurethemonlywiththemost

affordablecomponentsavailable.Somevaluelaptopsare

stripped-downmodelswithonlythebarestminimumof

components.Valuesystemsmaybetwogenerationsbehindthe

high-endlaptopswhenitcomestoperformanceandfeatures.

Forexample,itisquitecommonforvaluelaptopstouseIntel

CeleronorAMDSempronprocessors,whichsacrifice

performanceforpricewhencomparedtohigherpoweredCPUs.

Nevertheless,theabsolutedecreaseinfunctionalitybetween

successivegenerationsofprocessorsandotherfeaturesis

actuallyquitesmall.Althoughlow-costprocessorsmayhave

clockspeedsonlyhalfthatofthelatestgenerationofCPUs,the

actualperformancedifferencemaybesubstantiallysmaller.As



thenameimplies,theselaptopscanrepresentagoodvaluefor

thecustomer.

Valuesystemsgenerallyusechipsetswithintegratedgraphics,

whichalsosharessomeofthemainmemoryforgraphicsuse.

Also,theselaptopsareinvariablyequippedwiththesmallest

harddrivesavailablethesedays,40GB,withlargerdrivesasan

optionalupgrade.Theyalsogenerallyusetheslowest4200rpm

drives,whichcausessignificantlylongerbootand

hibernation/resumetimesaswellassloweroperationreading

andwritingfilesingeneral.Somemayincludewireless

networkingasstandardequipment,butthelowestcostmodels

mayofferwirelessasanextracostupgrade.Valuesystems

generallyinclude14-or15-inchdisplays,andpricesrangefrom

$500to$1,500ormore.



Thin&LightLaptops

Manyusersdonotneedtocarrytheequivalentofadesktop

aroundwiththem.Theyespeciallydonotwanttocarryaround

somethingthatweighscloseto10pounds.Fortheseusers,

manufacturershavecomeupwiththethin&lightclassof

laptops,whichattemptstocombineanoptimumamountof

portabilityandfunctionality.

Asthenamesuggests,thiscategoryoflaptopskeepsalow

profile,generallyaboutaninchinheight.Likewise,itsweightis

relativelylow,typicallyaround5pounds.

Despitethelowweight,theselaptopscanpackaconsiderable

amountofpowerandincorporatenumerousfeatures.The

processorisusuallyonegenerationremovedfromthefastest

available,butthispenalizesperformancebyonlyasmall

amount.Theavailablememoryandharddrivecapacityare

similarlyreducedbutstillhighlycapable.Also,tofitintoa1inchprofile,theselaptopsrequirethethinnestavailableoptical



Tài liệu bạn tìm kiếm đã sẵn sàng tải về

Chapter 2.  Portable PC Overview: Types and Features

Tải bản đầy đủ ngay(0 tr)

×
x