'Andouraccounts,'chimedRose.

'It'sprudenttomakeback-ups,'thecomputermantoldthemmock-sorrowfully,hisyoungfacemorehonestlyfullofscorn.'Alwaysmakeback-ups,ladies.'

'Whichvirus?'Iaskedagain.

Heshrugged,includingmeinhisstupidityrating.'MaybeMichelangelo...MichelangeloactivatesonMarch6thandthere'sstillalotofitabout.'

'Enlarge,'Isaid.

'Surelyyouknow?'

'IfIknew,I'veforgotten.'

Hespelleditoutastoanilliterate.'March6thisMichelangelo'sbirthday.IfyouhavetheviruslyingdoggoinyourcomputerandyouswitchonyourcomputeronMarch6th,thevirusactivates.'

'Mm.Well,March6thwaslastSunday.NooneswitchedonthiscomputeronSunday.'

Isobel'slargeeyesopenedwider.'That'sright.'

'Michelangeloisaboot-sectionvirus,'theexpertsaid,andtoourblank-lookingexpressionslong-sufferinglyexplained.'Justswitchingthemachineondoesthetrick.Simplyswitchingiton,waitingaminuteortwo,andswitchingoff.Switchingoniscalledbooting-up.AlltherecordsontheharddiskarewipedoutatoncewithMichelangeloandyougetthemessagesaying'Fataldiskerror'.That'swhat'shappenedtoyourmachine.Therecordsaregone.There'snoputtingthemback.'

Isobelstaredatme,conscience-stricken,appalledanddistressed.'Youdidtell.u.s.tomakeback-upfloppydisks,Iknowyoudid.Youkeptontellingus.I'meversosorry.I'msosorry.'

'Youshouldhaveinsisted,'Rosetoldme.'Imeanyoushouldhavemadeus.'

'Youdon'tevenseemworried,'Isobelsaid.

TothecomputermanIsaid,'Wouldthevirusactivateonbackupfloppydisks?'

'Prettylikely.'

'Butwe'vegothardlyany,'Isobelwailed.

Wedid,asithappened,havecomprehensiveback-updiskscontainingeverythingthetwosecretarieshadentereduptoandincludingthepreviousThursday.Iknewthey'dfoundthedailyback-upprocedureabitofabore.I'dseenthemleaveitfordays,sometimes.I'dremindedbothofthemoverandovertomakecopiesandwasawaretheythoughtInaggedthemunnecessarily.Thecomputerseemedeverlastinglyreliable.IntheendI'dtakentomakingdailyback-upsmyselfontheterminalinmysitting-room,storingthedisksinmysafe.Ifyouwantathingdoneproperly,asmymotherhadbeenaccustomedtosay,doityourself.

Atthatexactmoment,thoughthecopies.e.xisted,theycouldn'tbereachedowingtotheaxedstateofthesafe's...o...b..nations.

Icouldhaverea.s.suredthemallaboutourrecordsandnormallywouldhavedone.Suspicionstoppedme.SuspicionaboutIdidn'tknowwhat.But.i.twasaltogethertoomuchofacoincidenceformethatthecomputershouldcrashatthatparticulartime.

'You'renotalone,'thecomputermansaid.'Doctors,lawfirms,allsortsofbusinesses,havehadtheirrecordswipedout.Onewomanlostawholebookshewaswriting.Anditcostsnothingtomakeback-ups.'

'Ohdear.'Isobelwasneartears.

'Whatexactlyisavirus?'Roseenquiredmiserably.

'It'saprogrammethattellsthecomputertojumbleuporwipeouteverythingstoredinit.'Hewarmedtohissubject.'Thereareatleastthreethousandvirusesfloatingaround.There'sJerusalemIIthatactivateseveryFridaythethirteenth,that'saspeciallynastyone.It'scausedalotoftrouble,hasthatone.'

'Butwhat'sthepoint'?'Iasked.

'Vandalism,'hesaidcheerfully.'Destructionandwreckingforitsownsake.'Heranhisringersthroughhishair.'Forinstance,Icoulddesignasweetlittlevirusthatwouldmakeallyouraccountscomeoutwrong.NothingspectacularlikeMichelangelo,notacompletelossofeverything,justenoughtodriveyoumad.Justenoughtomakeerrorssothatyou'dbeforevercheckingandaddingandnothingwouldevercomeoutright.'Helovedtheidea,onecouldsee.'Onceyou'vewrittenaprogrammelikethat,youhavetospreadit.Imean,onecomputercancatchthevirusfromanother,that'sthebeautyofit.Allyouneedisafloppydiskwiththevirusinit.Feedthediskintoanycomputerandtransferthedataonthediskintothecomputer-whichisdoneallthetime-andbingo,thecomputerthenhasthevirusinsideit,lyinginwait.'

'Howdoyoustopit?'Iasked.

'Thereareallsortsofexpensiveprogrammesnowadaysfordetectingandneutralisingviruses.Andawholelotofpeoplethinkingupwaystoinventvirusesthatcan'tbegotridof.It'sawholeindustry.Lovely.Imean,rotten.'

Viruses,Ireflected,meantincome,tohim.

'Howdoyoufindoutifyouhaveavirus?'Iasked.

'Thewaytodoitistoscantheinfoinanygivencomputer.ThediskIusetodothathasmorethantwohundredofthecommonervirusesonit.Itwilltellyouifyou'vebeeninfectedbyMichelangeloorJerusalemII.Ifyou'dcalledmelastweek,Icouldhavedoneit.'

'Lastweekwesawnoneed,'Isaid.'And...um...ifthisMichelangelothingactivatesonlyonMarch6th,then.o.bviouslywedidn'thaveitonourcomputerlastyearonMarch6th.'

Ourexpertpartedwithmoreinformation.'MichelangelowasinventedsometimeafterMarch6thin1991andonlyworksonIBMcompatiblemachineslikeyours.'

'That'snocomfort,'Isaid.

'Er...no.Still,Icancleanupthesemachinesforyouandgiveyouavirus-freeset-upforthefuture.Butyouhavetobecarefulwhatyoufeedintocomputersfromtheoutside.Friendscanlendyouinfecteddisks.And...doyouhaveanyotherterminals?'

'There'soneinmyhouse,'Isaid.'Butsomeone'svandalisedit.'

Theexpertlookedshocked.'Youmean,adifferentvirus?'

'No,Idon't.Imeananaxe.'

Thephysicalsmashingofacomputerpainedhim,onecouldsee.Internalmalignantillnesseswerehisstockintrade.Axescameintomaliciousdamage,hesaid.

'Computervirusesaremaliciousdamage,itseemstome,'Isaid.

'Yes,but.i.t'sagame.'

'Notifyou'velostyourlife'swork,'Ipointedout.

'Ifyoudon'tmakeback-ups,you'reanutter.'

Iagreedwithhimentirelyaboutback-ups,butIdidn'tthinkvirusesagame.Ithoughtthemaswickedaschemicalwarfare.I'dheardofacomputervirusthathadwipedoutawholegeologicalsurveywiththeresultthatwellsforwaterweren'tdrilledintimeandmorethanathousandpeopleinadesertregiondied.Theauthorofthatparticularvirushadbeenreportedtobedelightedwithitseffectiveness.Toobadaboutthedead.

Isaid,'Isupposethere'snowayoftellingwhetherthisvirusofourswasintroducedintooursystemonpurpos...o...b..accident?'

Hestaredatmeearnestly,handbusythroughthehair.

'Itwouldbeunfriendlytodoitonpurpose.'

'Yes.'

'Mostvirusesarespreadbyaccident,likeAIDS.'

'Howlongcantheyliedormant?'

'Youcouldhaveavirusquitealongtimebeforeitwastriggeredintolife.'Hiseyesheldallthesadknowledgeofhisgeneration.'Youhavetotakeprecautions.'

ItoldhimIwishedwe'dknownhimsoonerandmentionedthenameofthefirmwehaddealtwithinthepast.

Helaughed.'Halfthecomputerstheysoldwereawashwithviruses.Theyusedinfecteddiagnosticdisksthemselvesandtheyusedtore-wrapvermin-riddendisksthatpeoplehadreturnedtotheminangerandsellthemagaintothegreatunsuspectingpublic.TheyvanishedovernightbecausetheyknewMarch6thwouldmeananarmyoffuriouscustomerssuingtheirpantsoff.EventhoughMarch6thwasaSunday,we'vedozensofcaseslikeyourstocleanupthisweek.Notourowncustomers,b.u.t.theirs.'

Isobellookedshocked.'b.u.t.theywerealwayssoniceandhelpful,comingoutherewheneverweneededthem.'

'Andfeedinginprogrammesthatwouldkeepyouneedingthem,Ishouldn'twonder,'theexpertsaidwithonlyhalf-disguisedadmiration.

'Ifyoudothattome,'Isaidpleasantly,'yourpantswillbeoffforlife.'

Heregardedmethoughtfully.'Iwouldn't,'hesaid,andadded,asifsafeguardinghimselffromfutureaccusationsofwhichhewouldbeinnocent,'Don'tforgetthecommonestreasonforlosingallfilesispiloterror.Imean,youcanwipeeverythingofftheharddiskjustbytypingDELforDelete,followedbyaDirectoryidentification.'

Welookedblank.

HesaidtoIsobel,'SupposeyoutypedDELstarfullstopstar,that'sallitwouldtake.JustaseffectiveasMichelangelo.You'dloseeverythingforever.'

'No!'Shewashorrified,predictably.

'Yes,'hesmiled.'Butpeoplewhowritevirusesseenofuninthat.'

'Butwhy?'Isobelasked,unhappilywailing.'Whydopeoplewanttowritevirusestocausesuchtrouble?'

'Toshowoff,'Isaid.

Theexpert'seyeswidened.Hedidn'tcareovermuchforthata.s.sessment,Ithought.Hetendedtoomuchtoadmiretheexpertise,notdespisetheself-indulgence.

'Well,'hesaidslowly,'it'struealotofvirus-writerssigntheirnamesintotheprogrammes.There'sonecalledEddie,he'sinventedseveral.'

'Justputusbackinbusiness,'Iinterrupted,tiringsuddenlyofthewholesubject.'Keepuscleanfromnowonwithregularchecks.We'llworkoutamaintenanceagreement.'

'Delighted,'hesaid,thehanddoingdoubletimethroughthehair.'You'llbeupandrunningbytomorrow.'

Ilefthimpreparingtogowhilewritingalist(expensive)ofwhatwewouldneed,andwentalongtomyownofficetotelephonethemakersofmysafe.

'Anaxe'?'Theyexclaimed,shocked.'Areyousure?'

'Ineedthesafeopened,'Iconfirmed.'Whatcanyoudoandhowsoon?'

Theygavemethephonenumberoftheirnearestagent.Thenearestagentwouldnodoubtsendalocksmithtolook-see.Thankyou,Isaid.

Thenearestagentsoundedunenthusiasticanddoubtfullysuggestedavisitthefollowingweek.

'Tomorrow,'Isaid.

Therewasasharpintakeofbreath.Icouldimaginethepursedlips,thejudicialshakingofthehead.PossiblyFridayafternoon,theysaid.Possibly.Asagreatfavourtheymightmanageit.

IputthephonedownreflectingthatifImyselfletthatsortofgeneralback-pedallingunwillingnesscreepintoresponsestorequestsformyservices,I'dbetwiddlingmythumbsinnotime.NotonlydidImyselfdriveanywhereanytimeifIhadnootherdriveravailable,butoftenatfiveminutes'noticeI'dhireanextrahorseboxfromarivalsoasnottoturnworkdown.I'dalmostneverbeenunabletogetwheelsoutontheroad.Itwasamatterofpride,ofcourse,b.u.t.thesortofpridethatgotthingsdone.

AzizcameintotheofficetocollectthekeysoftheFourtrakinordertodriveLizzietoHeathrow.Ihandedthemtohimandreflexivelyaskedhimtodrivehercarefully.

'Slowdownforroundabouts?'heasked,eyesbrilliant.

'Oh,G.o.d.'Ifeltlikelaughingforthefirsttimethatmorning.'Yeah.Gethertotheshuttleontime.'

Whenhe'dgone,Isatforawhilethinkingofthisandthat,andthenIphonedthecomputerexpertagain.Heansweredatonce,reportingcontentedlythathewasfixingyetanotherMichelangelocasualtyanda.s.suringmehe'dbebackwithustomorrowmorning.

'Fine,'Isaid,'but...er...couldyouansweraquestion?'

'Fireaway.'

Isaid,'Canyouchangethedateinthecomputer?CouldyouchangeitsinternalclocksothatMarch6thinthecomputerwouldn'tturnupatall?CouldyouchangeMarch6thtoMarch7th?'

'Sure,'hesaidreadily.'It'sawellknownwayofavoidingMarch6th.SwitchtheclockforwardtoMarch7ththenswitchitbacktotherightdateacoupleofdayslater.Easy,ifyouknowwhatyou'redoing.'

'And...youcouldadvanceorr.e.t.a.r.dMarch6thsothat.i.tactivatedontheactualMarch5thorontheactualMarch7th?'

'Yes.'Apause.'Thatwouldbepositivemalice.You'dhavetoknowtheviruswasinthere.'

'But.i.twouldbepossible?Possibletochangethehours,too?'

'Yes.'

'Howlongwouldittakeyoutochangetheclock?'

'Mepersonally?Sayaminute,maximum.'

'AndifIdiditmyself?'

'Well,'hesaidthoughtfully,'ifsomeonewrotedownforyouexactlywhattodo,stepbystep,orifyouhadaninstructionbook,you'dhavetoallowmaybefiveminutesofprivacy,becauseyou'dhavetoconcentrate.'Hepausedagain.'Doyouseriouslythinksomeonechangedyourclock?Becauseit'ssettotherightdateandtimenow,I'lltellyou.'

'Idon'tknow,'Isaid.'Ijustasked.'

'Anytime,'hereplied.'Solong.Seeyoutomorrow.'

Iwasfightingshadows,Ithought.Seeingvillainsbehindeverybush.Thegreatprobabilitywasthatmycomputer,likesomanyothers,hadaccidentallycrashed.Andifithadn't...thensomewhereinitsrecordstheremustbeinformationIneededforunlockingsurroundingmysteries.InformationthatsomefoeorothermustknowIpossessed.

Todestroytherecords,itwaseasiesttotypeDELstarfullstopstar.Yettodothatonehadtobepresent,andthediskfailurewouldbeinstantaneous.Changingthecomputer'sclocktoactivateMichelangelomeantthatanyfuturehourcouldbechosen,likeatimebombgoingoff.

SandySmithdrovehispolicecarintothefarmyardandparkeditoutsidetheofficewindow.Hecameintojoinme,takingoffhispeakedcapandsitting,uninvitedbutwelcome,inthechairacrossfrommine.

Jogger'sinquest,'hesaid,wipinghisforehead.

'Howdiditgo?'

Heshrugged.'Openedandadjourned,likeIsaid.Iidentifiedhim.DrFarwaygaveevidenceofdeath.Thecoronerlookedatthephotosandhe'dreadthepost-mortemreport.Headjournedpendingfurtherenquiries.'Sandysigheddeeply.'I'dbetterwarnyouhewasn'thappy.IhearditsaidthatJoggerdiedfromcrushinganddislocationoftheatlasandthattherewereparticlesofrustembeddedinhisskinatthesiteoftheinjury.'

'Rust!'Irepeated,notlikingit.