THE PORTABLE WEBSITE.docx

THE PORTABLE WEBSITE.docx

《THE PORTABLE WEBSITE.docx》由会员分享，可在线阅读，更多相关《THE PORTABLE WEBSITE.docx（14页珍藏版）》请在冰点文库上搜索。

THEPORTABLEWEBSITE

THEPORTABLEWEBSITE

ByDanaiKuangparichat

ABSTRACT

Thispaperdescribesanimplementationofaportablewebsite:

asite=carriedaroundonandupdatedthroughalaptopcomputer.Thesiteissupposedto=mirrorasiteontheWorldWideWeb;whenthelaptopisconnectedtotheInternet,the=publicsiteistobeupdatedtomatchthesitecurrentlyonthelaptop.Mirrorsiteson=othercomputersneedtobeallowedtobecreated,too.Beforeembarkingonatrip,the=updaterofthesitetakesasnapshotofthesiteontoaCD-ROM.Theapproachtakeninthis=paperistosetupadirectoryofsymboliclinksonthelaptop=92sharddrive,andto=copyoverthoselinkswhentheuserwishestomodifyafileontheCD.Thisapproachkeeps=trackofchangestothesiteviaupdatefiles,whicharekeptbothonthelaptopand=atthepublicsite.

INTRODUCTION

Withtoday=92sexplosivegrowthoftheInternet,webserversarepoppingup=everywhere.Likewise,moreandmorepeoplearelearninghowtogetaroundtheNetevery=day.AlthoughtheInternethasspreadthroughoutallofAmerica,aswellasmanyother=countries,therestillexistmanyplacesintheworldthathaveverylimitedaccesstothe=Internet,andsomethathavenoaccessatall.Whenonetravelstoanareawithlimited=Internetaccess,hemaydesiretoupdatearemotewebsitefrequently;however,due=totheunavailabilityoftheInternet,thisupdatingisnotalwayspossible.

Thesolutionistodesignaportablewebsite,asystemtohandlethe=organizationofthewebsitechangesbetweenInternetsessionssothatduringthesesessions,=theremotewebsitecanbeupdatedquicklyandeasily.Thissystemcanbestoredona=laptopwhichiscarriedaroundbythewebsite=92sowner.Whenevertheownerdesiresto=makeachangetothesite,hechangesitlocally;thenthenexttimeheconnectstothe=Internet,heuploadsallofthechangeshehasmadetotheremotewebsite.

Ofcourse,theownerisnottheonlypersonwhowillwanttoaccesshisweb=site.Althoughtheremotewebsitecanbemadepubliclyaccessible,theremaybe=interesteduserswhoonlyhavelimitedaccesstotheInternet;thus,theymayalsowant=tokeeplocalcopiesofthewebsite.Therefore,thesystemalsoneedstoallow=easycopyingofthesitefromthelaptopandeasydownloadingofupdatesonthewebsite.

Severalassumptionsaretobemadewhendesigningthissystem.Thewebsite=ontheInternetisstoredonaUNIXfilesystem.Thelaptopontowhichthesiteis=copiedalsousesaUNIXfilesystemandincludesaCD-ROMdrive,afloppydiskdrive,=andaharddrive.BeforeeachtriptoanInternet-deprivedarea,theowneroftheweb=sitecancopyitscurrentcontent（andmaybeotherfiles）ontoanynumberofCD-ROMs;=however,theCD-ROMcannotberewrittenduringthetrip.Therefore,localupdatescan=onlybemadetothelaptop=92sharddrive（andanyfloppydiskstheownermaywantto=carry）.Theothercomputersontowhichthewebsiteiscopiedanddownloaded,however,mayuse=anymodernfilesystem,andmightnotevenincludeaCD-ROMdrive.Thepagesofthe=sitemaycontainlinktootherpagesinthesamesite,butnonetoothersites.Itisalso=assumedthatthepersonwhokeepsthelocalwebsiteonthelaptopistheonlypersonwho=haswriteaccesstotheremotewebsite.

Topreventconfusion,Iwilldefineherethelocalwebsiteasthe=sitestoredontheowner=92slaptop;theclonesitesasthecopiesofthesiteon=otheruser=92scomputers;andthehomesiteasthesiteontheWorldWideWeb.=Ownerreferstothepersonwhomanagesthehomesiteandcarriesthelocal=site.

Inthesystempresentedhere,theorganizationoffilesonthelocalsite=andclonesitesusessymboliclinkstotheCD-ROMextensivelyinordertosaveharddrive=space.However,thehomesite（andanyclonesiteonasystemthatdoesnotallowlinksor=doesnothaveaCD-ROMdrive）doesnotuselinksatallbecauseallofthepagesarestored=onthesamedevice;sosavingspaceisnotanissue.Thissystemalsousesseveral=filestokeeptrackofwhichpageshavebeenmodified,andwhentheyweremodified.These=filesareusedtofacilitateuploading,downloading,andcopyingofthesitesothat=copyingeveryfileisnotalwaysnecessary.

DESIGNCRITERIA

Theportablewebsitemustsupportthefollowingfeatures:

Localsiteupdating.Anytimetheownerdesirestomodifythesitein=anyway,hecandosoimmediatelyonhislaptop.Thelocalsiteshouldcontainthemost=up-to-dateversionatalltimeswhentheowneristravelling.

Homesiteupdating.WhentheownerconnectstotheInternet,hecan=updatethehomesitetomatchthecurrentlocalsite.

Clonesitecreationfromlocalsite.Theownercancreateanewclone=siteonanothercomputerfromhislaptop.Thisnewsitewouldmatchthecurrentlocalsite.=TheothercomputermightormightnotuseaCD-ROM,anditmaybeusinganymodern=filesystem.

Otherfeaturesthatshouldbeaddedifpossibleincludethefollowing:

Clonesitecreationfromhomesiteoranotherclonesite.Anyuser=shouldbeabletocreateanewclonesitethatmatchesthesitefromwhichitwascreated.

Clonesiteupdating.Naturally,onewaytoupdateaclonesitewouldbe=toeraseit,andthencopyordownloadthenewestversiontorecreatetheclone.But=havingasystemthatcanupdateclonesitesquickly,eitherfromthehomesiteorthelocal=site,ismuchmoredesirable.

Thereareanumberofwaystoimplementthesefeatures.However,someways=aremoredesirablethanothers.Herearethecriteriatobeusedtodeterminethe=usefulnessofthesystem:

Easeofuse.Alltheoperations--downloading,uploading,copying--=shouldnotonlybeeasytoperform,butalsoeasytoexplain.Thefewerstepsanoperation=requires,thelessroomthereisforusererror.Additionally,theownerwillneedto=explaintousersofclonesiteshowtoupdatetheirclones;iftheprocessistoo=complicated,theymaymisunderstandorforgettheowner=92sexplanation.

Simplicityindesign--Complexsystemsleavelotsofroomforerror.=Theyarealsodifficulttoimplementanddebug.

Efficientuseofdiskspace--Portablecomputerscanonlycarryso=much..Thus,weneedtomanagethediskspacewellatthelocalsite,butstillinclude=filesnecessarytoalloweasyupdatingandcreationofwebsites.Becausewedonotknowhow=powerfulthecomputersareonwhichclonesiteswillbecreated,weshouldpreparefor=theworstandassumethattheirdiskspaceswillbelimitedalso.Althoughthehomesite=shouldalsoprovideefficientdiskspacemanagement,itisnotasimportantasforthe=othertwotypesofsites.Ifthehomesiterunsoutofdiskspace,theownercansimplybuy=anewharddrive.Newharddrivesmaynotbeaspracticalonlaptopsandthecomputers=carryingtheclonesites,though.

Speed.Mostpeopledesirenottowaitalongtimewhendownloading,=uploading,orcopyingfiles.Naturally,ifthewebsiteislarge,suchwaitingmaybe=unavoidable,butthesystemshouldminimizethetimeittakestoupdateandcreateweb=sites.

Flexibilityfortheowner.Thesystemshouldplaceasfewconstraints=aspossibleontheupdatingofthelocalwebsite.Ideally,theownershouldbeableto=modifythelocalsitetothesameextentthathecanmodifythehomesite.Asimpleexample=wouldbeaddinganewpage:

Naturally,thelocalsiteisvirtuallyrequiredtoallow=suchanoperation.Amorecomplicatedexamplewouldbereorganizingdirectories:

=Movingfilesbetweendirectories,creatingnewdirectories,orremovingdirectoriesmay=notbeeasytoupdateonthehomesiteorclonesites;thus,somedesignsofthesystemmay=restrictsuchactions.

Flexibilityincreatingclones.Thesystemshouldbeabletobecloned=onawidevarietyofcomputers.Themorepeopletherearethatcanclonethesite,=themoreusefulthewebsitewillbe.

Reliability.Thesystemshouldnotleavealotofroomforfailure.=Thechancesoffailurearelesslikelyiftheprocessesaremadesimpler,andiftheuser=isnotgivenalotofrestrictions.Thesystemshouldalsodoredundantcheckstoseeif=everythingisoperatingasexpected.

DESIGNDESCRIPTION

FILEORGANIZATION

Thissystemrequiresthatwebpagesuserelativeurlsforlinkstoother=pages.Becausethepagesaregoingtobecopiedtoothersites,absoluteurlswouldbe=illogical:

Oncethepageiscopiedover,anabsoluteurlwouldbecomeinvalid.Although=thisrequirementdecreasestheflexibilityonwhattheownercando,itismucheasierthan=allowingabsoluteurls,andthenchangingallthoseurlsineachpagecopiedto=anothermachine.

Beforetheownerembarksonatravel,theCD-ROMshouldcontainallofthe=websitefilesastheyareorganizedonthehomesite;inotherwords,allfilesshouldbe=containedinthesamedirectoriesastheonesatthehomesite.Thedirectorystructure=shouldalsobecreatedonthelaptop=92sharddrive.Withinthesedirectories,symbolic=linksshouldbecreatedforeachfileinthewebsite（butnotforthedirectories）.These=linksshouldhavethesamenamesasthefileswithwhichtheyarelinkedandshouldbein=thesamedirectories（butontheharddriveinsteadoftheCD-ROM）.Whenevera=browserisopenedonthelaptop,itshouldonlyreaddirectlyfromtheharddrive.Although=therecreationofthedirectorystructureontheharddrivetakesextrawork,itmakes=updatingthesitemucheasier.BecausetheCD-ROMisread-only,readingdirectlyfromthe=CD-ROMwouldberatherimpractical;anytimeapageischanged,therewouldbenowaytolet=thebrowserknownottoreadfromtheCD-ROMforthatpage.

Iftheownerdecidestomodifya