1 00:00:00,000 --> 00:00:03,395 >> [Music kucheza] 2 00:00:03,395 --> 00:00:13,100 3 00:00:13,100 --> 00:00:15,570 >> DAVID J. Malan: Hivyo mimi tu Alitaka kuwahakikishia kwa. 4 00:00:15,570 --> 00:00:18,260 Napenda kurudia nini hasa Scaz Alisema kuhusu kumbukumbu ya kitaasisi. 5 00:00:18,260 --> 00:00:20,350 CS50 imekuwa karibu kwa baadhi ya miaka 20 katika Harvard. 6 00:00:20,350 --> 00:00:22,280 Na ukweli ni, kutoka wazee juu ya chini, 7 00:00:22,280 --> 00:00:25,045 kuna kila mwaka reassurance kwamba freshmen, sophomores, 8 00:00:25,045 --> 00:00:26,870 na juniors na pia wazee kuchukua 9 00:00:26,870 --> 00:00:30,360 CS50, kwamba kuishia kufanya faini. 10 00:00:30,360 --> 00:00:32,680 >> Ukweli ni, wanafunzi wala kushindwa CS50. 11 00:00:32,680 --> 00:00:35,740 Kwa kweli, katika matukio adimu ambapo tulikuwa na Es au Fs, 12 00:00:35,740 --> 00:00:37,990 ni kweli kuwa kwa sababu ya hali extenuating, 13 00:00:37,990 --> 00:00:39,840 kama ni matibabu au binafsi. 14 00:00:39,840 --> 00:00:41,830 Ds ni incredibly makali pia. 15 00:00:41,830 --> 00:00:45,270 Na naweza kusema kwa raha, hata kama sisi kawaida hawana kufichua takwimu, 16 00:00:45,270 --> 00:00:48,450 lakini kutokana na kwamba hakuna kumbukumbu ya kitaasisi hapa wowote, 17 00:00:48,450 --> 00:00:51,810 Wengi wa wanafunzi katika CS50 je kuishia kupata mbalimbali darasa. 18 00:00:51,810 --> 00:00:54,720 Chunk kubwa kuishia kuishia katika B mbalimbali pia. 19 00:00:54,720 --> 00:00:57,490 >> Hivyo hata ingawa unaweza kuwa equating watatu watatu yako akili 20 00:00:57,490 --> 00:01:00,690 na 60% na hivyo Ds, au Cs, au kama, 21 00:01:00,690 --> 00:01:02,530 ni kweli haina kujipanga up na ukweli. 22 00:01:02,530 --> 00:01:05,238 Kwa kweli, tuna maana sawa kabisa sisi kusema mwanzoni mwa muhula 23 00:01:05,238 --> 00:01:08,380 kwamba wanafunzi wengi katika CS50, wote Cambridge na hapa katika New Haven, 24 00:01:08,380 --> 00:01:10,220 hawajawahi kuchukuliwa kozi CS kabla. 25 00:01:10,220 --> 00:01:13,090 Na nini kweli hatimaye mambo Hapa ndipo wewe kuishia katika wiki 12 26 00:01:13,090 --> 00:01:15,882 jamaa na wewe mwenyewe katika wiki sifuri. 27 00:01:15,882 --> 00:01:17,590 Sasa tuna nyingi inafuatilia katika mwendo 28 00:01:17,590 --> 00:01:20,548 kama wewe know-- chini ya starehe, zaidi starehe, mahali fulani katika kati. 29 00:01:20,548 --> 00:01:23,790 Na hakika, wakati kupata takwimu juu ya jaribio wiki hii, 30 00:01:23,790 --> 00:01:27,460 wala kuwa na tamaa kama, hasa kama wewe kujisikia kwamba wewe ni karibu maana 31 00:01:27,460 --> 00:01:30,780 au chini ya maana au wastani, hasa kwa vile sisi kufanya si lazima 32 00:01:30,780 --> 00:01:33,560 kuchukua wale idadi ya watu zote maanani katikati ya muhula 33 00:01:33,560 --> 00:01:35,000 na takwimu grading. 34 00:01:35,000 --> 00:01:37,250 >> Kwa maneno mengine, tunajua takwimu kila mwaka 35 00:01:37,250 --> 00:01:39,570 kwamba wanafunzi ambao ni chini vizuri, kufanya kidogo mbaya zaidi juu ya jaribio. 36 00:01:39,570 --> 00:01:42,050 Na wanafunzi ambao ni vizuri zaidi kufanya vizuri kidogo juu ya jaribio. 37 00:01:42,050 --> 00:01:45,430 Lakini kwa kuwa ahadi katika mtaala na pia katika wiki ya kwanza ya mihadhara, 38 00:01:45,430 --> 00:01:46,880 sisi kuchukua yote ya kwamba katika akaunti. 39 00:01:46,880 --> 00:01:48,900 >> Hakika, katika miaka ya mwisho, nini sisi kuishia kufanya 40 00:01:48,900 --> 00:01:52,154 ni normalizing alama zote nchini sehemu, katika Cambridge 41 00:01:52,154 --> 00:01:54,570 na sasa hapa katika New Haven, ambayo ina maana kwa kuzingatia 42 00:01:54,570 --> 00:01:57,310 mitindo tofauti, tofauti ukali, aina mbalimbali 43 00:01:57,310 --> 00:02:00,722 ya haiba kwamba mtu binafsi TAS na hapa na katika Cambridge 44 00:02:00,722 --> 00:02:02,930 hivyo kwamba wewe si katika hasara hata kama wewe tu 45 00:02:02,930 --> 00:02:06,120 kutokea kwa kuwa na TF au TA ambao imekuwa kidogo kali juu ya wewe 46 00:02:06,120 --> 00:02:07,170 katika akili yako. 47 00:02:07,170 --> 00:02:10,139 >> Mbili, sisi kuchukua katika akaunti ya faraja ngazi na historia halisi, au ukosefu 48 00:02:10,139 --> 00:02:13,310 yake, wakati kuchukua Jaribio alama katika akaunti. 49 00:02:13,310 --> 00:02:14,830 Hivyo wale wawili ni factored katika. 50 00:02:14,830 --> 00:02:17,142 Na mwisho wa siku, kwa sababu ni mara ya kesi 51 00:02:17,142 --> 00:02:19,100 kwamba mwanafunzi kuishia katika sehemu chini comfy 52 00:02:19,100 --> 00:02:24,250 wakati yeye au yeye kweli ni mali katika katika-kati ya au kinyume chake, 53 00:02:24,250 --> 00:02:26,230 kila kitu ni hivyo incredibly mtu mmoja mmoja. 54 00:02:26,230 --> 00:02:29,560 Hakika, utakuwa kupata annoyed saa yetu katika mwisho wa muhula wakati sisi ni marehemu 55 00:02:29,560 --> 00:02:32,630 kuwasilisha darasa yako kwa sababu kwa Scaz, Yasoni, na Andy, na mimi, 56 00:02:32,630 --> 00:02:35,430 na timu wamefanya Cambridge ni halisi 57 00:02:35,430 --> 00:02:38,480 kuwa na mamia ya barua pepe nyuma na nje na kila mia ya kozi 58 00:02:38,480 --> 00:02:41,279 TAS, hapa na katika Cambridge, kuwauliza nini 59 00:02:41,279 --> 00:02:44,070 wanafikiri ya yote ya wanafunzi wao kulingana na rasimu ya darasa. 60 00:02:44,070 --> 00:02:46,230 Na kila kitu hapo baada ya ni incredibly mtu mmoja mmoja. 61 00:02:46,230 --> 00:02:49,230 Hivyo kwa kiasi sisi kupata kujua wewe katika masaa ya ofisi, sehemu, na zaidi, 62 00:02:49,230 --> 00:02:51,350 yote hayo pia ni kuchukuliwa katika akaunti. 63 00:02:51,350 --> 00:02:55,210 >> Hivyo hata kama sisi huwa na kutumia hii mitano kumweka wadogo, tafadhali, ungua mwenyewe 64 00:02:55,210 --> 00:02:57,492 kutoka dhana kwamba tatu bila ya shaka ni 60%. 65 00:02:57,492 --> 00:02:58,450 Ni ni maana ya kuwa nzuri. 66 00:02:58,450 --> 00:03:01,360 Na wasaidizi mafundisho wanashtakiwa katika mrefu kuanza 67 00:03:01,360 --> 00:03:04,050 kujaribu kuweka alama katika wawili-wawili, na watatu watatu, 68 00:03:04,050 --> 00:03:06,590 na kikundi cha watu wane mbalimbali ili tuweze kweli kuwa nafasi ya kukua. 69 00:03:06,590 --> 00:03:08,610 Na sisi kweli kuwa kigezo ambacho 70 00:03:08,610 --> 00:03:11,086 tunaweza kukupa muhimu maoni kuhusu jinsi unafanya 71 00:03:11,086 --> 00:03:12,210 na jinsi wewe ni inaendelea. 72 00:03:12,210 --> 00:03:15,130 Hivyo tafadhali kuchukua kwamba kwa moyo. 73 00:03:15,130 --> 00:03:20,565 >> Je, kuna maswali naweza kusaidia kushughulikia au wasiwasi naweza kusaidia kuwahakikishia? 74 00:03:20,565 --> 00:03:23,800 Au ahadi siwezi kujaribu kuweka? 75 00:03:23,800 --> 00:03:24,690 Hakuna? 76 00:03:24,690 --> 00:03:25,330 SAWA. 77 00:03:25,330 --> 00:03:26,010 >> Sawa. 78 00:03:26,010 --> 00:03:28,970 Hivyo kwa kuwa alisema, hii ni CS50. 79 00:03:28,970 --> 00:03:31,670 Huu ni mwanzo wa wiki sita hapa nchini New Haven. 80 00:03:31,670 --> 00:03:33,820 Hebu tuanze na mafupi dimming ya taa 81 00:03:33,820 --> 00:03:37,439 kuweka hatua kwa maudhui ya leo. 82 00:03:37,439 --> 00:03:38,105 [VIDEO avspelning] 83 00:03:38,105 --> 00:03:44,045 [Music kucheza] 84 00:03:44,045 --> 00:03:46,600 Hapo akaja na ujumbe. 85 00:03:46,600 --> 00:03:50,300 86 00:03:50,300 --> 00:03:52,900 Na itifaki zake wote mwenyewe. 87 00:03:52,900 --> 00:04:06,417 88 00:04:06,417 --> 00:04:13,090 Yeye alikuja ulimwengu wa firewalls baridi, asiyejali ruta, na hatari mbaya zaidi 89 00:04:13,090 --> 00:04:16,079 kwamba kifo. 90 00:04:16,079 --> 00:04:21,079 Yeye ni haraka, yeye ni imara, yeye ni TCP / IP. 91 00:04:21,079 --> 00:04:23,120 Na yeye got anwani yako. 92 00:04:23,120 --> 00:04:25,820 93 00:04:25,820 --> 00:04:29,268 Wapiganaji wa wavu. 94 00:04:29,268 --> 00:04:29,917 >> [Mwisho avspelning] 95 00:04:29,917 --> 00:04:31,000 DAVID J. Malan: zote haki. 96 00:04:31,000 --> 00:04:32,030 Hii ni CS50. 97 00:04:32,030 --> 00:04:33,820 Huu ni mwanzo wa wiki sita. 98 00:04:33,820 --> 00:04:37,270 Na hii ni mwanzo wa kuangalia yetu katika biashara na mtandao programu. 99 00:04:37,270 --> 00:04:41,220 Na, pengine zaidi excitingly, leo ni alama ya mpito kwa ajili yetu 100 00:04:41,220 --> 00:04:43,780 kutoka mstari amri yetu dunia ya C kwa mtandao 101 00:04:43,780 --> 00:04:47,020 msingi ulimwengu wa PHP, na HTML, na CSS, na SQL, na JavaScript, 102 00:04:47,020 --> 00:04:49,800 na hivyo zaidi kwamba ni juu ya upeo wa macho. 103 00:04:49,800 --> 00:04:53,390 >> Lakini kwanza, ni amekuja usikivu wetu katika kutembea katika chuo kwamba kuna 104 00:04:53,390 --> 00:04:57,914 ni baadhi ya bafu hapa mjini New Bandari inayoitwa Harvard chumba, ambayo 105 00:04:57,914 --> 00:04:59,080 ni kidogo greyed nje hapa. 106 00:04:59,080 --> 00:05:03,830 Lakini kwa kweli, mtu akaenda wakati na gharama ya etching katika Harvard chumba 107 00:05:03,830 --> 00:05:05,700 juu ya hii hapa chumba. 108 00:05:05,700 --> 00:05:07,790 Asante kwa hilo. 109 00:05:07,790 --> 00:05:11,020 Siwezi kusema tuna analog katika Cambridge bado, 110 00:05:11,020 --> 00:05:14,060 lakini nadhani tuna mradi mdogo kwa wenyewe sasa wakati sisi kurudi nyuma. 111 00:05:14,060 --> 00:05:15,890 Hivyo kuwashukuru kwa hilo. 112 00:05:15,890 --> 00:05:18,340 >> Hivyo haraka kuangalia nyuma katika ambapo sisi kushoto mbali wiki iliyopita 113 00:05:18,340 --> 00:05:21,010 na wapi utaenda hii kuja wiki na matatizo kuweka tano. 114 00:05:21,010 --> 00:05:24,350 Hivyo katika tatizo kuweka tano, wewe utakuwa na changamoto ya kutekeleza spellchecker. 115 00:05:24,350 --> 00:05:26,630 Na kwa kufanya hivyo, wewe utakuwa na mitupu maandishi pretty kubwa 116 00:05:26,630 --> 00:05:29,160 faili na kama 140,000 maneno ya Kiingereza. 117 00:05:29,160 --> 00:05:32,610 Na wewe utakuwa na changamoto ya kuamua juu ya muundo wa data na ambayo 118 00:05:32,610 --> 00:05:35,340 wanataka mzigo wote wa maneno hayo katika kumbukumbu, na katika RAM, 119 00:05:35,340 --> 00:05:38,470 na kisha kutekeleza majukumu machache, moja ambayo ni kwenda kuwa kuangalia. 120 00:05:38,470 --> 00:05:41,555 Ambapo wakati kupita hoja, neno, kazi yako kuangalia 121 00:05:41,555 --> 00:05:43,430 tu ni kwenda na kusema kweli au uongo, 122 00:05:43,430 --> 00:05:44,990 hii ni neno katika kamusi. 123 00:05:44,990 --> 00:05:47,110 >> Lakini wewe ni kwenda kuwa na baadhi ya kubuni busara na changamoto 124 00:05:47,110 --> 00:05:48,568 linapokuja suala la utekelezaji wa jambo hilo. 125 00:05:48,568 --> 00:05:51,250 Katika utekelezaji rahisi, ungeweza hakika 126 00:05:51,250 --> 00:05:53,960 kutekeleza spellchecker katika kamusi msingi 127 00:05:53,960 --> 00:05:55,380 na ni aina gani ya muundo wa data? 128 00:05:55,380 --> 00:05:57,796 Wewe tu haja ya kuhifadhi nzima rundo la masharti katika kumbukumbu? 129 00:05:57,796 --> 00:06:00,074 Nini kwenda kujibu kutoka wiki mbili labda? 130 00:06:00,074 --> 00:06:00,740 Watazamaji: Array. 131 00:06:00,740 --> 00:06:01,500 DAVID J. Malan: Unaweza kutumia safu. 132 00:06:01,500 --> 00:06:02,750 Na si kwamba wote kuwa mbaya. 133 00:06:02,750 --> 00:06:05,631 Lakini si lazima kujua mapema jinsi kubwa ya safu 134 00:06:05,631 --> 00:06:08,630 wewe ni kwenda haja, kama huna kujua faili lazima mapema. 135 00:06:08,630 --> 00:06:10,110 Hivyo wewe ni kwenda kuwa na kutumia kidogo ya hila 136 00:06:10,110 --> 00:06:11,970 kama malloc, kama sisi kuanza kutumia. 137 00:06:11,970 --> 00:06:13,977 Au tunaweza kushughulikia kwamba wasiwasi kwa kutumia 138 00:06:13,977 --> 00:06:16,810 nini muundo wengine data hiyo ni Imekuwa aina ya kukuza pembezoni 139 00:06:16,810 --> 00:06:17,894 juu ya safu? 140 00:06:17,894 --> 00:06:18,810 Watazamaji: wanaohusishwa orodha. 141 00:06:18,810 --> 00:06:21,270 DAVID J. Malan: Kama wanaohusishwa orodha, eti sisi kupata baadhi mabadiliko. 142 00:06:21,270 --> 00:06:22,686 Lakini kuna zaidi kidogo gharama. 143 00:06:22,686 --> 00:06:24,150 Tuna kuyatumia kudumisha. 144 00:06:24,150 --> 00:06:25,890 Na umefanya bado kutolewa hii juu, lakini kuna dhahiri 145 00:06:25,890 --> 00:06:28,473 kuwa kidogo zaidi utata kuliko tu kwa kutumia mabano mraba 146 00:06:28,473 --> 00:06:30,080 na kuruka karibu safu. 147 00:06:30,080 --> 00:06:33,340 >> Lakini safu ya mbio wakati, kama wewe ni kwa ajili ya kutafuta neno, 148 00:06:33,340 --> 00:06:34,179 yapate kuingia ya n. 149 00:06:34,179 --> 00:06:35,970 Lakini tena, inaweza kuwa kidogo zisizo yasiyo na maana 150 00:06:35,970 --> 00:06:38,734 kujenga kwamba safu si kujua ukubwa mapema. 151 00:06:38,734 --> 00:06:41,150 Orodha wanaohusishwa ingawa, kama wewe tu kuhifadhi rundo la masharti 152 00:06:41,150 --> 00:06:43,300 katika orodha wanaohusishwa, nini juu amefungwa yako 153 00:06:43,300 --> 00:06:46,920 juu ya kukimbia wakati kwenda kuwa kutafuta kwa kuangalia neno au katika orodha hiyo? 154 00:06:46,920 --> 00:06:47,700 >> Watazamaji: n. 155 00:06:47,700 --> 00:06:50,575 >> DAVID J. Malan: Yeah, O kubwa ya n au linear kwa sababu katika hali mbaya zaidi, 156 00:06:50,575 --> 00:06:52,640 neno ni kama Z neno njia yote mwishoni. 157 00:06:52,640 --> 00:06:55,350 Na kwa sababu ya orodha wanaohusishwa, kwa sababu mishale wale na msingi, 158 00:06:55,350 --> 00:06:58,280 katika orodha moja moja wanaohusishwa, tu kwenda kutoka mwelekeo mmoja hadi mwingine, 159 00:06:58,280 --> 00:06:59,590 huwezi kuruka kote. 160 00:06:59,590 --> 00:07:01,160 Una kufuata yao wote. 161 00:07:01,160 --> 00:07:05,505 >> Hivyo sisi mapendekezo mwishoni mwa wiki iliyopita, wiki tano, kwamba kuna njia bora zaidi. 162 00:07:05,505 --> 00:07:08,727 Na kwa kweli, grail takatifu ingekuwa kweli kuwa wakati mara kwa mara 163 00:07:08,727 --> 00:07:10,560 ambapo wakati unataka kwa kuangalia juu ya neno, wewe 164 00:07:10,560 --> 00:07:13,370 kupata jibu papo bila kujali ya jinsi maneno mengi tayari 165 00:07:13,370 --> 00:07:14,350 katika kamusi yako. 166 00:07:14,350 --> 00:07:17,680 >> Hii ni mpenyo msanii wa nini unaweza wito meza hash. 167 00:07:17,680 --> 00:07:21,900 Na meza hash ni aina ya nzuri amalgam wa array-- inayotolewa wima 168 00:07:21,900 --> 00:07:26,416 hapa, tu because-- na kisha wanaohusishwa list-- kuteka usawa hapa. 169 00:07:26,416 --> 00:07:28,790 Na meza hash inaweza kuwa kutekelezwa katika mashada ya njia. 170 00:07:28,790 --> 00:07:34,110 Hii Excerpt kutoka vitabu vya kiada hutokea kutumia tarehe hizo za watu kuzaliwa 171 00:07:34,110 --> 00:07:38,940 kama njia ambayo ni kuamua mahali pa kuweka jina la mtu. 172 00:07:38,940 --> 00:07:41,230 Hivyo hii ni kamusi kama wewe ya majina. 173 00:07:41,230 --> 00:07:45,240 Na ili kuharakisha kuweka majina katika muundo huu data, 174 00:07:45,240 --> 00:07:49,280 wao kuangalia, inaonekana, watu hawa wa kuzaliwa ulianza kwa heshima na mwezi. 175 00:07:49,280 --> 00:07:50,570 >> Hivyo ni 1-31. 176 00:07:50,570 --> 00:07:52,910 Na kusahau kuhusu Februari na kona kesi kama hiyo. 177 00:07:52,910 --> 00:07:57,050 Na kama siku yako ya kuzaliwa ni mnamo Januari 1, au Februari 1, au Desemba 1, 178 00:07:57,050 --> 00:07:59,890 wewe ni kwenda kuishia katika kwanza kabisa mlolongo juu juu. 179 00:07:59,890 --> 00:08:02,150 Kama tarehe yako ya kuzaliwa ni kama 25 ya mwezi, 180 00:08:02,150 --> 00:08:04,567 wewe ni kwenda kuishia katika ndoo namba 25. 181 00:08:04,567 --> 00:08:07,400 Na kama kuna mtu huko tayari katika yoyote ya maeneo hayo, nini 182 00:08:07,400 --> 00:08:10,470 wewe kuanza kufanya na haya wanaohusishwa orodha ni wakitengeneza yao pamoja 183 00:08:10,470 --> 00:08:14,320 ili uweze kuwa na holela idadi ya watu, au kitu chochote, 184 00:08:14,320 --> 00:08:15,580 katika eneo hilo. 185 00:08:15,580 --> 00:08:18,400 >> Hivyo kuwa aina ya mchanganyiko wa wakati mara kwa mara kwa hashing. 186 00:08:18,400 --> 00:08:21,160 Na kwa hash kitu maana yake ni kuchukua kama pembejeo kama mtu, 187 00:08:21,160 --> 00:08:25,360 au wake au jina yake, au wake au kuzaliwa kwake tarehe, na kisha kuamua juu ya baadhi ya pato 188 00:08:25,360 --> 00:08:29,780 kulingana na kwamba, kama kuangalia yao kuzaliwa na outputting moja kupitia 31. 189 00:08:29,780 --> 00:08:31,900 >> Hivyo basi unaweza kuwa na muda kidogo linear, 190 00:08:31,900 --> 00:08:34,429 lakini katika hali halisi, na kama katika kesi ya tatizo kuweka tano, 191 00:08:34,429 --> 00:08:36,220 sisi siyo kwenda kuwa kufanya kazi katika P kuweka tano 192 00:08:36,220 --> 00:08:40,059 sana kuhusu asymptotic mbio muda, kama kasi ya chini kinadharia 193 00:08:40,059 --> 00:08:41,809 na ambayo algorithm ili kukimbia. 194 00:08:41,809 --> 00:08:44,330 Tunakwenda huduma ya juu idadi halisi ya sekunde 195 00:08:44,330 --> 00:08:47,350 na kiasi halisi ya kumbukumbu, idadi halisi ya ka ya kumbukumbu 196 00:08:47,350 --> 00:08:48,140 unatumia. 197 00:08:48,140 --> 00:08:52,710 Hivyo kusema ukweli, kuwa moja kubwa mlolongo wa kama watu milioni moja 198 00:08:52,710 --> 00:08:56,710 ni pretty damn polepole kama wewe ni kutafuta kwa jina katika orodha ya milioni ukubwa. 199 00:08:56,710 --> 00:08:59,830 >> Lakini nini kama wewe kugawanya kwamba orodha ya juu katika sehemu 31? 200 00:08:59,830 --> 00:09:04,400 Kutafuta 31/1 ya kwamba super orodha ndefu, katika hali halisi, 201 00:09:04,400 --> 00:09:05,741 ni hakika kwenda kuwa kasi zaidi. 202 00:09:05,741 --> 00:09:07,240 Asymptotically, ni kitu kimoja. 203 00:09:07,240 --> 00:09:08,860 Wewe ni kugawa tu kwa sababu mara kwa mara. 204 00:09:08,860 --> 00:09:10,651 Na kukumbuka kuwa sisi kutupa mambo hayo mara moja. 205 00:09:10,651 --> 00:09:13,486 Lakini katika hali halisi, ni kwenda kuwa mara 31 kwa kasi zaidi. 206 00:09:13,486 --> 00:09:16,110 Na kwamba ni nini tunakwenda kuanza kujiinua katika P kuweka tano. 207 00:09:16,110 --> 00:09:18,750 >> Hivyo P kuweka tano pia pia inapendekeza kwamba wewe kufikiria 208 00:09:18,750 --> 00:09:21,810 kidogo kisasa zaidi muundo wa data aitwaye trie. 209 00:09:21,810 --> 00:09:24,420 Na trie ni mti kama muundo data. 210 00:09:24,420 --> 00:09:26,672 Lakini badala ya kuwa duru kidogo au mistatili 211 00:09:26,672 --> 00:09:28,380 kama sisi kuendelea kuchora kwa nodes, ni kweli 212 00:09:28,380 --> 00:09:30,840 ina arrays nzima kwa nodes yake. 213 00:09:30,840 --> 00:09:33,430 Na hata kama hii ni kidogo abstract hapa kuangalia, 214 00:09:33,430 --> 00:09:35,450 Zamyla katika P seti ya kutembea kupitia kutembea wewe 215 00:09:35,450 --> 00:09:37,580 kupitia kwa undani zaidi juu ya hili. 216 00:09:37,580 --> 00:09:39,980 Hii ni muundo wa data kwamba badala cleverly 217 00:09:39,980 --> 00:09:44,130 wanaweza kuwa kila nodi kuwa safu ukubwa 26, A kupitia Z au sifuri 218 00:09:44,130 --> 00:09:45,320 kwa njia ya 25. 219 00:09:45,320 --> 00:09:49,260 Na wakati unataka kuingiza mtu jina katika muundo huu data au kupata 220 00:09:49,260 --> 00:09:53,990 kwake, nini kufanya, kama jina ni kama Maxwell, M-A-X-W-E-L-L, 221 00:09:53,990 --> 00:09:57,900 wewe kwanza kuangalia M. Na kisha Rukia sambamba M eneo 222 00:09:57,900 --> 00:09:59,100 katika safu ya kwanza. 223 00:09:59,100 --> 00:10:02,400 Wewe kisha kuruka kwa A, kwanza eneo katika safu ijayo, 224 00:10:02,400 --> 00:10:03,610 kufuatia mishale. 225 00:10:03,610 --> 00:10:08,300 Kisha X, basi W, basi E, basi L, basi L, na kisha labda baadhi ya mwisho ya pekee 226 00:10:08,300 --> 00:10:11,850 tabia, baadhi mwangalizi kwamba anasema neno haachi hapa. 227 00:10:11,850 --> 00:10:14,780 >> Na nini ni nzuri kuhusu Haya na kukumbuka kwamba picha hapa, 228 00:10:14,780 --> 00:10:16,797 taarifa jinsi kando kando ya kila safu ni kukatwa. 229 00:10:16,797 --> 00:10:19,630 Hiyo ni kwa sababu tu jambo hili bila kuwa mkubwa na wa kutisha kwa kuangalia 230 00:10:19,630 --> 00:10:20,338 katika juu ya screen. 231 00:10:20,338 --> 00:10:21,820 Hivyo ni excerpted. 232 00:10:21,820 --> 00:10:25,920 Nini kizuri kuhusu mbinu hii ni kwamba kama kuna milioni majina tayari 233 00:10:25,920 --> 00:10:30,890 katika muundo huu data, jinsi hatua nyingi gani kuchukua mimi kuingiza Maxwell? 234 00:10:30,890 --> 00:10:36,450 M-A-X-W-E-L-L-- kama saba-ish hatua ya kuingiza au kuangalia kwa Maxwell. 235 00:10:36,450 --> 00:10:39,320 >> Tuseme kuna trilioni majina katika muundo huu data. 236 00:10:39,320 --> 00:10:41,900 Jinsi hatua nyingi gani kuchukua mimi kutafuta Maxwell? 237 00:10:41,900 --> 00:10:43,450 M-A-X-- bado saba. 238 00:10:43,450 --> 00:10:45,770 >> Na humo uongo kinachojulikana wakati mara kwa mara. 239 00:10:45,770 --> 00:10:47,960 Kama tukidhani kwamba maneno ni hakika imepakana 240 00:10:47,960 --> 00:10:52,150 na wahusika 20, au 46 wahusika, au baadhi integer sababu ndogo, 241 00:10:52,150 --> 00:10:53,790 basi ni kwa ufanisi wa mara kwa mara. 242 00:10:53,790 --> 00:10:57,790 Na hivyo kuingizwa na kutafuta trie ni super haraka. 243 00:10:57,790 --> 00:10:59,540 Bila shaka, sisi kamwe kupata kitu chochote kwa ajili ya bure. 244 00:10:59,540 --> 00:11:02,740 Na hata kama pengine si dived katika P kuweka tano bado, 245 00:11:02,740 --> 00:11:06,596 nini bei ni sisi pengine kulipa kwa kupata kwamba mkuu ufanisi wakati hekima? 246 00:11:06,596 --> 00:11:07,470 >> Watazamaji: Kumbukumbu. 247 00:11:07,470 --> 00:11:08,390 >> DAVID J. Malan: Kumbukumbu, sawa? 248 00:11:08,390 --> 00:11:10,240 I mean, tumekuwa si inayotolewa picha nzima hapa. 249 00:11:10,240 --> 00:11:12,823 Hii Excerpt kutoka vitabu vya kiada hana inayotolewa wote wa arrays. 250 00:11:12,823 --> 00:11:16,687 Kuna kiasi kikubwa cha kumbukumbu na tu null kuyatumia ambayo si kuwa kutumika. 251 00:11:16,687 --> 00:11:17,520 Hivyo ni biashara mbali. 252 00:11:17,520 --> 00:11:21,050 Na kutakuwa na kuachwa na wewe katika P kuweka tano kuamua juu ya njia ambayo unataka kwenda. 253 00:11:21,050 --> 00:11:24,460 >> Sasa hii wazo la hashing, kama kando, ni kweli super imefikia. 254 00:11:24,460 --> 00:11:27,980 Hivyo kwa hash thamani maana, kabisa tu, kwa kuchukua kitu kama pembejeo 255 00:11:27,980 --> 00:11:29,220 na kuzalisha pato. 256 00:11:29,220 --> 00:11:31,270 Hivyo heshi ni algorithm. 257 00:11:31,270 --> 00:11:34,990 >> Na kwa ujumla, kazi hash lengo katika maisha ni kuchukua kitu kama pembejeo 258 00:11:34,990 --> 00:11:39,655 na kuzalisha idadi kama pato, kama namba moja kupitia 31 au A kupitia Z, 259 00:11:39,655 --> 00:11:40,960 sifuri kwa njia ya 25. 260 00:11:40,960 --> 00:11:44,250 Hivyo inachukua pato tata na akirudi ni chini ya kitu 261 00:11:44,250 --> 00:11:46,310 hiyo ni kidogo zaidi manufaa na kusimamiwa. 262 00:11:46,310 --> 00:11:49,250 >> Na hivyo ni zamu nje katika kazi maarufu sana 263 00:11:49,250 --> 00:11:51,160 kwamba dunia ya usalama na dunia ya binadamu 264 00:11:51,160 --> 00:11:53,060 wamekuwa wakitumia kwa miaka inaitwa SHA1. 265 00:11:53,060 --> 00:11:56,260 Hii ni pretty dhana za hisabati fomula kwamba hana kimsingi huo. 266 00:11:56,260 --> 00:11:58,870 >> Wewe kuchukua kweli kubwa chunk ya zeros na ones-- 267 00:11:58,870 --> 00:12:01,530 ambayo inaweza kuwa megabyte muda mrefu, gigabyte long-- 268 00:12:01,530 --> 00:12:05,930 na akirudi ni chini ya tu bits wachache, bits wachache, 269 00:12:05,930 --> 00:12:09,082 ili uweze kuwa na idadi kama moja kupitia 31, au kupitia Z. 270 00:12:09,082 --> 00:12:11,540 Lakini katika hali halisi, ni kidogo kubwa kuliko tu kupitia Z. 271 00:12:11,540 --> 00:12:16,640 >> Kwa bahati mbaya, sisi ni katika nusu ya kile mtu playfully aitwaye SHAppening 272 00:12:16,640 --> 00:12:19,840 ambapo dunia ni kuhusu mwisho katika pengine miezi michache 273 00:12:19,840 --> 00:12:22,617 wakati kwa sababu watafiti, tu wiki hii iliyopita, 274 00:12:22,617 --> 00:12:25,700 lilichapisha ripoti kuwa kinyume na nini watafiti usalama kuwa na mawazo 275 00:12:25,700 --> 00:12:29,810 kwa muda fulani, na tu kutumia kuhusu, nini ilikuwa hivyo, 276 00:12:29,810 --> 00:12:33,420 Nadhani ilikuwa ni $ 175,000-- fedha nyingi, 277 00:12:33,420 --> 00:12:36,540 lakini si haziwezi kufikiwa na mbaya zaidi hasa watu wabaya, 278 00:12:36,540 --> 00:12:41,560 au mbaya zaidi hasa countries-- $ 175,000 wangeweza kununua mengi ya kukodi server 279 00:12:41,560 --> 00:12:42,690 nafasi katika wingu. 280 00:12:42,690 --> 00:12:44,619 Na tutaweza kurudi kwa wingu kabla ya muda mrefu. 281 00:12:44,619 --> 00:12:47,410 Lakini ni njia tu kukodisha server nafasi kwenye kama watumishi Microsoft, 282 00:12:47,410 --> 00:12:50,285 au Google, au Amazon, au kama ambapo unaweza kulipa kwa dakika 283 00:12:50,285 --> 00:12:51,670 kutumia kompyuta ya mtu mwingine. 284 00:12:51,670 --> 00:12:54,250 >> Na zinageuka kama unaweza kulipa mtu mwingine kukopa kompyuta zao 285 00:12:54,250 --> 00:12:56,730 na kukimbia kificho kwamba umefanya imeandikwa juu yake na kutumia mzuri dhana 286 00:12:56,730 --> 00:13:01,580 hisabati, unaweza kimsingi takwimu jinsi ya mtu heshi ni 287 00:13:01,580 --> 00:13:05,320 kazi, na kupewa pato lake, kubadili mhandisi nini mchango wake ni. 288 00:13:05,320 --> 00:13:08,590 Na kwa madhumuni ya leo, inatosha kusema, hii ni mbaya. 289 00:13:08,590 --> 00:13:12,540 Kwa sababu SHA1 na hash kazi kama ni kawaida ni super 290 00:13:12,540 --> 00:13:17,050 kutumika katika maombi ya usalama, uhusiano encrypted kwenye mtandao, 291 00:13:17,050 --> 00:13:21,890 shughuli za benki, simu za mkononi encryption kwa simu yako kiini, na kadhalika. 292 00:13:21,890 --> 00:13:24,880 Na hivyo yeyote wakati mtu anaona njia ya kubadili 293 00:13:24,880 --> 00:13:28,510 mhandisi moja ya teknolojia hizi au kuvunja, mambo mabaya yanaweza kutokea. 294 00:13:28,510 --> 00:13:30,300 >> Sasa dunia tayari alijua hili. 295 00:13:30,300 --> 00:13:31,310 Hii ilikuwa ni inayoonekana. 296 00:13:31,310 --> 00:13:34,670 Na dunia tangu wakiongozwa na SHA1 kwa SHA256, 297 00:13:34,670 --> 00:13:37,320 ambayo ni njia tu ya dhana ya akisema wanatumia vipande kubwa. 298 00:13:37,320 --> 00:13:40,570 Na kwa kweli, hata CS50 ya mwenyewe tovuti kuboreshwa mwaka jana to-- 299 00:13:40,570 --> 00:13:43,290 si kwamba sisi uso yote haya wengi vitisho kujaribu kupata katika PDFs 300 00:13:43,290 --> 00:13:46,520 na whatnot-- lakini tovuti CS50 anatumia kubwa heshi, 301 00:13:46,520 --> 00:13:47,980 ambayo ina maana kwamba tutakuwa na salama. 302 00:13:47,980 --> 00:13:50,020 Basi wote wa PDFs yako Itakuwa salama, lakini si 303 00:13:50,020 --> 00:13:52,880 lazima fedha yako au kitu chochote hasa binafsi au ya kibinafsi 304 00:13:52,880 --> 00:13:53,380 kutumia. 305 00:13:53,380 --> 00:13:56,550 Sp kuangalia nje kwamba URL kama wewe d kama baadhi ya maelezo ya ziada. 306 00:13:56,550 --> 00:13:59,840 >> Hivyo tatizo kuweka tano ni Hakika kwenye upeo wa macho. 307 00:13:59,840 --> 00:14:01,560 Jaribio moja ni hii Jumatano ijayo. 308 00:14:01,560 --> 00:14:04,479 Lakini kuchukua faida ya ofisi masaa, wote usiku wa leo na kesho. 309 00:14:04,479 --> 00:14:07,770 Na pia kuchukua faida ya masaa ya ofisi, kama wewe ni inapatikana, haki baada ya hii. 310 00:14:07,770 --> 00:14:11,550 Wafanyakazi na mimi itabidi fimbo karibu na kufanya zaidi ya kawaida Maswali na Majibu kwa kuongeza usiku wa leo. 311 00:14:11,550 --> 00:14:16,610 Na napenda sana kumbuka hapa, kwa wale wa kwetu hapa mjini New Haven-- 312 00:14:16,610 --> 00:14:19,360 hivyo ni kabisa kwa Scaz ya hotuba waliona, mimi nina uhakika, 313 00:14:19,360 --> 00:14:21,140 kama kidogo ya mapambano makali. 314 00:14:21,140 --> 00:14:24,627 Na kwa sifa, kama wewe si kujifunza tayari au kusikia 315 00:14:24,627 --> 00:14:27,710 kutoka baadhi ya marafiki katika Harvard, kujua hapa ni baadhi ya taasisi kumbukumbu mpya. 316 00:14:27,710 --> 00:14:30,790 P kuweka tano aina ya aina ya inaelekea kuwa gumu katika CS50, 317 00:14:30,790 --> 00:14:32,590 au changamoto nyingi kwa wanafunzi wengi. 318 00:14:32,590 --> 00:14:37,180 >> Lakini nini maana ni kwamba tuko karibu juu ya kilima huu. 319 00:14:37,180 --> 00:14:38,270 Na kwa kweli mimi maana hii. 320 00:14:38,270 --> 00:14:40,728 Ni changamoto kubwa, lakini pia ni zawadi zaidi 321 00:14:40,728 --> 00:14:43,560 kwa kuwa tofauti na wengi kila mengine utangulizi sayansi ya kompyuta 322 00:14:43,560 --> 00:14:47,980 Bila shaka katika Marekani kwamba sisi kujua ya, wanafunzi wengi hawana kumaliza intro 323 00:14:47,980 --> 00:14:51,400 Bila shaka baada ya tayari kutekelezwa mambo kama miti, na inajaribu, 324 00:14:51,400 --> 00:14:52,880 na meza hash, na kadhalika. 325 00:14:52,880 --> 00:14:54,770 >> Na hivyo mimi matumaini, na sisi matumaini kwamba wewe ni 326 00:14:54,770 --> 00:14:57,280 kuwa na hisia kubwa sana ya kuridhika hata 327 00:14:57,280 --> 00:15:00,760 kama wiki moja au mbili kupitia ambayo kupata kuridhika kwamba 328 00:15:00,760 --> 00:15:02,490 haina kujisikia kidogo kama hii. 329 00:15:02,490 --> 00:15:05,250 Lakini ngoja kuwahakikishia, sisi tu na seti nne P kushoto. 330 00:15:05,250 --> 00:15:07,380 Hivyo aina ya kwamba juu ni mbele. 331 00:15:07,380 --> 00:15:12,370 >> Kwa upande mwingine wa jambo hilo, matumaini yetu, ni rolling tu milima na mawingu. 332 00:15:12,370 --> 00:15:16,000 Na tuseme, puppies ni upande wa pili. 333 00:15:16,000 --> 00:15:18,340 Hivyo wewe tu na hutegemea katika huko kwa muda mrefu kidogo. 334 00:15:18,340 --> 00:15:22,050 I mean, kwa kweli kama sisi kuanza kipindi cha mpito katika ulimwengu wa programu ya mtandao, 335 00:15:22,050 --> 00:15:26,060 utapata kwamba mambo become-- hii ni adorable kweli. 336 00:15:26,060 --> 00:15:29,680 337 00:15:29,680 --> 00:15:33,490 Sawa, tutaweza baada URL hii baadaye. 338 00:15:33,490 --> 00:15:36,140 Utakuta pia kwamba tuko kufikia aina ya Plateau 339 00:15:36,140 --> 00:15:38,150 ambapo kila kitu ni Hakika bado kisasa 340 00:15:38,150 --> 00:15:40,170 na changamoto na kubuni, lakini wewe si 341 00:15:40,170 --> 00:15:42,590 kwenda kujisikia kama sisi ni daima kwenda juu ya kilima huu. 342 00:15:42,590 --> 00:15:44,390 Hivyo kuchukua baadhi ya faraja katika jambo hilo. 343 00:15:44,390 --> 00:15:47,409 >> Hivyo bila wasiwasi zaidi, hebu kuanza kufanya hii mpito soko 344 00:15:47,409 --> 00:15:49,950 katika muhula katika ulimwengu wa mtandao, na kwa kweli dunia 345 00:15:49,950 --> 00:15:51,420 na ambayo sisi sote ni zaidi ya ukoo. 346 00:15:51,420 --> 00:15:53,753 Sisi tumepewa vifaa biashara katika mifuko yetu, juu ya madawati yetu, 347 00:15:53,753 --> 00:15:55,127 katika Backpacks wetu, na kadhalika. 348 00:15:55,127 --> 00:15:56,210 Ni kwa jinsi gani wote wa kazi hii? 349 00:15:56,210 --> 00:15:59,077 Na tunawezaje kuanza kuandika kificho kwamba siyo super arcane 350 00:15:59,077 --> 00:16:01,910 na katika baadhi blinking maandishi haraka kuwa hakuna wa rafiki yako au familia 351 00:16:01,910 --> 00:16:04,659 ni milele kwenda kutaka kuingiliana pamoja, lakini kitu unaweza kuweka 352 00:16:04,659 --> 00:16:06,660 kwenye simu zao, au juu ya mtandao browsers zao, 353 00:16:06,660 --> 00:16:09,010 au juu ya vifaa yoyote na ambao wao kuingiliana. 354 00:16:09,010 --> 00:16:10,430 >> Hivyo hapa ni nyumba ya mtu. 355 00:16:10,430 --> 00:16:14,040 Na ndani ya nyumba hii ni ya wanandoa wa Laptops, wanandoa wa umri wa desktop shule 356 00:16:14,040 --> 00:16:17,470 kompyuta, kitu kinachoitwa router au kitovu katikati, 357 00:16:17,470 --> 00:16:20,310 na kisha baadhi ya aina ya Modem cable au DSL Modem. 358 00:16:20,310 --> 00:16:24,560 Na kisha kuna biashara, kwa ujumla inayotolewa kama kuna wingu juu angani. 359 00:16:24,560 --> 00:16:29,230 >> Hivyo picha hii, ingawa aina kidogo ya tarehe, 360 00:16:29,230 --> 00:16:32,604 hakika Ukamataji nini zaidi ya pengine katika nyumba yako, 361 00:16:32,604 --> 00:16:35,520 au kwa ufanisi kile nyote na katika vyumba Dorm wako, au vyumba, 362 00:16:35,520 --> 00:16:36,480 au kama. 363 00:16:36,480 --> 00:16:40,010 >> Kwa hiyo kile ni kweli kinachoendelea wakati kujaribu kutumia biashara leo? 364 00:16:40,010 --> 00:16:42,010 Hivyo kila kompyuta katika biashara, ni zamu nje, 365 00:16:42,010 --> 00:16:46,860 anahitaji kuwa na anwani ya kipekee, kiasi kama sisi katika ulimwengu halisi haja 366 00:16:46,860 --> 00:16:52,050 anwani ya posta, kama 51 matarajio Mitaani, New Haven, Connecticut, au 33 367 00:16:52,050 --> 00:16:54,170 Oxford Street, Cambridge, Massachusetts. 368 00:16:54,170 --> 00:16:58,520 Hivyo kufanya kompyuta kwenye mtandao haja njia ya kipekee ya kushughulikia wenyewe. 369 00:16:58,520 --> 00:17:01,180 >> Hiyo ni hivyo kwamba wakati kompyuta moja anataka kuzungumza na mwingine, 370 00:17:01,180 --> 00:17:04,525 inaweza kutuma ujumbe na kuwajulisha mpokeaji ambaye 371 00:17:04,525 --> 00:17:05,900 ni lazima kutuma majibu nyuma. 372 00:17:05,900 --> 00:17:07,900 Hivyo ni tu hufanya aina ya maana Intuitive labda 373 00:17:07,900 --> 00:17:09,980 kwamba kila kitu na pepe ya aina fulani. 374 00:17:09,980 --> 00:17:11,240 >> Lakini jinsi gani unaweza kupata anwani? 375 00:17:11,240 --> 00:17:13,589 Naam, kama wewe kupata hapa chuo, au unaweza kwenda nyumbani 376 00:17:13,589 --> 00:17:15,760 na kurejea kwenye yako mbali au kompyuta desktop, 377 00:17:15,760 --> 00:17:17,770 na ama kuziba katika au kuungana na Wi-Fi, 378 00:17:17,770 --> 00:17:19,569 zinageuka kuwa kuna server maalum 379 00:17:19,569 --> 00:17:22,089 kwenye mitandao wengi aitwaye DHCP server. 380 00:17:22,089 --> 00:17:23,880 Kweli haina jambo nini hii anasimama kwa, 381 00:17:23,880 --> 00:17:26,660 lakini ni nguvu jeshi Configuration itifaki, ambayo ni tu 382 00:17:26,660 --> 00:17:29,760 njia dhana ya kusema, hii ni kompyuta kuwa ama Yale ina, 383 00:17:29,760 --> 00:17:32,600 au Harvard ina, au Comcast ina, au Verizon ina, 384 00:17:32,600 --> 00:17:35,100 au kampuni yako ina, ambao lengo katika maisha, 385 00:17:35,100 --> 00:17:38,810 wakati kusikia mtu wapya aliongeza na mtandao, ni kusema hapa, 386 00:17:38,810 --> 00:17:40,010 kutumia anwani hii. 387 00:17:40,010 --> 00:17:42,790 >> Hivyo sisi wanadamu hawana kwa kificho kwa bidii katika kompyuta yetu 388 00:17:42,790 --> 00:17:44,040 nini anwani yetu ya kipekee ni. 389 00:17:44,040 --> 00:17:47,070 Sisi tu kugeuka juu, kufungua mfuniko, na kwa namna fulani seva hii 390 00:17:47,070 --> 00:17:52,210 kwenye mtandao wa ndani tu ananiambia kwamba anwani yangu ni 51 Prospect Street, au 33 391 00:17:52,210 --> 00:17:53,940 Oxford Street, au kama. 392 00:17:53,940 --> 00:17:56,000 >> Sasa ni si kwenda kuwa hivyo verbose kama hiyo. 393 00:17:56,000 --> 00:18:00,210 Badala nini mimi kwenda kupata ni numeric anuani aitwaye IP. 394 00:18:00,210 --> 00:18:01,960 IP maana internet itifaki. 395 00:18:01,960 --> 00:18:06,025 Na ni tabia mbaya kwa wakati huu katika maisha yako, pengine kusikia au kuona neno IP, 396 00:18:06,025 --> 00:18:08,140 au kwa ujumla kutupwa ni kuzunguka labda. 397 00:18:08,140 --> 00:18:10,720 Lakini kwa kweli, ni pretty sawa mbele kitu. 398 00:18:10,720 --> 00:18:13,610 >> IP ni dotted alisema idadi, 399 00:18:13,610 --> 00:18:17,150 ambayo ina maana ni kitu nukta kitu dot dot kitu fulani. 400 00:18:17,150 --> 00:18:21,980 Na kila moja ya somethings wale hutokea kuwa idadi kati ya 0 na 255. 401 00:18:21,980 --> 00:18:26,710 >> Hivyo kulingana na muda wa wiki tano pamoja ya CS50, ikiwa nambari hizi kila aina 0-255, 402 00:18:26,710 --> 00:18:28,713 jinsi wengi bits ni kila ya ishara hizo namba? 403 00:18:28,713 --> 00:18:29,420 >> Watazamaji: Nane. 404 00:18:29,420 --> 00:18:30,100 >> DAVID J. Malan: Ni got kuwa nane. 405 00:18:30,100 --> 00:18:31,933 Hivyo kwa jumla, ni wangapi bits ni anwani ya IP? 406 00:18:31,933 --> 00:18:32,710 Watazamaji: 32. 407 00:18:32,710 --> 00:18:33,820 >> DAVID J. Malan: Hivyo 32. 408 00:18:33,820 --> 00:18:35,830 8 pamoja na 8 pamoja na 8 pamoja na 8 ni 32. 409 00:18:35,830 --> 00:18:38,767 Jinsi anwani jumla IP wengi iwepo katika ulimwengu? 410 00:18:38,767 --> 00:18:39,600 Watazamaji: bilioni 4. 411 00:18:39,600 --> 00:18:42,410 DAVID J. Malan: Hivyo takribani nne bilioni kwa sababu hiyo ni 2 32 madarakani. 412 00:18:42,410 --> 00:18:44,410 Na kama huwezi aina ya grok kuwa katika akili yako, 413 00:18:44,410 --> 00:18:47,470 tu kujua kwamba 32-bit maadili inaweza kuwa kubwa kama bilioni 4 414 00:18:47,470 --> 00:18:49,140 ikiwa ni maadili yote mazuri. 415 00:18:49,140 --> 00:18:52,500 Hivyo kwamba maana kuna bilioni 4 Inawezekana IP duniani. 416 00:18:52,500 --> 00:18:55,090 >> Na funny hadithi, tuko aina ya mbio nje ya yao. 417 00:18:55,090 --> 00:18:59,720 Na kwa kweli ni tatizo kubwa kwa kuwa dunia pia aliona tatizo hili ijayo, 418 00:18:59,720 --> 00:19:03,639 lakini si lazima waliitikia hivyo kwa njia haraka zaidi iwezekanavyo. 419 00:19:03,639 --> 00:19:05,680 Na hakika, mara moja umefanya kumaliza CS50 na kuanza 420 00:19:05,680 --> 00:19:06,950 kulipa kipaumbele katika dunia tech, utasikia 421 00:19:06,950 --> 00:19:08,520 kuona hii ni sana kawaida ufadhili. 422 00:19:08,520 --> 00:19:12,260 >> Kwa mfano, kama sisi kwenda kweli umri wa shule siku hizi, Y2K. 423 00:19:12,260 --> 00:19:13,570 Hiyo ilikuwa ni kweli si mshangao. 424 00:19:13,570 --> 00:19:15,700 Kama kila mtu alijua kwa Miaka 1,000 kwamba kwamba 425 00:19:15,700 --> 00:19:20,250 was-- zaidi ya elfu years-- kwamba kwamba alikuwa hatimaye kwenda kutokea. 426 00:19:20,250 --> 00:19:23,295 Na bado, sisi waliitikia ni sana katika dakika ya mwisho. 427 00:19:23,295 --> 00:19:24,420 Na yale yanayotokea tena. 428 00:19:24,420 --> 00:19:26,740 Hivyo leo tutaweza majadiliano juu ya IP toleo la 4. 429 00:19:26,740 --> 00:19:29,250 Lakini tunajua kwamba dunia ni hatimaye kupata 430 00:19:29,250 --> 00:19:31,590 karibu na kuwaendeleza na kitu kinachoitwa IPv6, 431 00:19:31,590 --> 00:19:34,540 ambayo badala ya 32-bit anwani, uses-- mtu yeyote 432 00:19:34,540 --> 00:19:36,443 wanataka kuchukua nadhani, ni wangapi bits? 433 00:19:36,443 --> 00:19:37,310 >> Watazamaji: 64? 434 00:19:37,310 --> 00:19:38,380 >> DAVID J. Malan: nadhani nzuri, lakini hakuna. 435 00:19:38,380 --> 00:19:39,975 Sisi ni hatimaye kujaribu kupata mbele ya Curve. 436 00:19:39,975 --> 00:19:40,558 >> Watazamaji: 128. 437 00:19:40,558 --> 00:19:43,490 DAVID J. Malan: 128, ambayo ni freaking idadi kubwa 438 00:19:43,490 --> 00:19:46,250 ya IP, kwa sababu hiyo ni kama mara 2, mara 2, 439 00:19:46,250 --> 00:19:49,620 mara 2, mara nyingi wawili-wawili kutoka bilioni 4. 440 00:19:49,620 --> 00:19:50,530 >> Hivyo kama wadadisi. 441 00:19:50,530 --> 00:19:54,110 Ni zamu nje na mimi tu googled hii kupata hii out-- Yale kompyuta, 442 00:19:54,110 --> 00:19:58,910 hapa katika Yale, huwa na kuanza na hizi numbers-- 130.132 nukta kitu, 443 00:19:58,910 --> 00:20:00,669 na 128.36 dot kitu. 444 00:20:00,669 --> 00:20:02,710 Lakini kuna shaka isipokuwa katika bodi 445 00:20:02,710 --> 00:20:05,334 kulingana na idara ya mambo na jengo na chuo uko juu. 446 00:20:05,334 --> 00:20:09,310 Harvard inaelekea kuwa 140.247, au 128.103. 447 00:20:09,310 --> 00:20:11,530 Na kwa ujumla hii ni Maelezo haina maana, 448 00:20:11,530 --> 00:20:13,260 lakini ni kitu unaweza taarifa sasa. 449 00:20:13,260 --> 00:20:15,593 Baada ya kuanza poking kuzunguka mazingira kwenye kompyuta yako, 450 00:20:15,593 --> 00:20:18,540 unaweza kuanza kwa taarifa hizi aina ya mifumo kabla ya muda mrefu. 451 00:20:18,540 --> 00:20:23,470 >> Lakini wakati uko nyumbani na kuwa na Apple Uwanja wa Ndege, au kifaa Linksys, 452 00:20:23,470 --> 00:20:26,560 au D-Link, au chochote ni wazazi wako au ndugu imewekwa 453 00:20:26,560 --> 00:20:28,890 katika nyumba yako, vizuri nini pengine 454 00:20:28,890 --> 00:20:30,800 ni kile kinachoitwa IP binafsi. 455 00:20:30,800 --> 00:20:34,850 Na hawa ndio kweli nzuri, muda ufumbuzi 456 00:20:34,850 --> 00:20:38,050 na tatizo la kuendesha mfupi juu ya anwani ya IP. 457 00:20:38,050 --> 00:20:40,382 >> Na nini unaweza kufanya na mitandao nyumbani, typically-- 458 00:20:40,382 --> 00:20:42,340 na kusema ukweli, hata Yale na Harvard ni mapya 459 00:20:42,340 --> 00:20:46,840 kufanya hivyo katika areas-- tofauti ni wewe inaweza kutoa kundi zima la kompyuta 460 00:20:46,840 --> 00:20:50,360 moja IP muda mrefu kama wewe kuweka kifaa maalum mbele yao, 461 00:20:50,360 --> 00:20:52,410 kitu kinachoitwa ruta, au inaweza kuitwa 462 00:20:52,410 --> 00:20:54,060 wakala au idadi yoyote ya mambo mengine. 463 00:20:54,060 --> 00:20:56,710 Lakini kifaa hakika kwamba ina kuwa hotuba mmoja IP. 464 00:20:56,710 --> 00:20:59,450 Na kisha nyuma kwamba kifaa, ndani ya jengo, 465 00:20:59,450 --> 00:21:03,030 ndani ya nyumba au ghorofa, inaweza kuwa idadi yoyote ya kompyuta, ambayo yote 466 00:21:03,030 --> 00:21:06,460 na IP kwamba kuanza na mmoja wa haya tarakimu hapa. 467 00:21:06,460 --> 00:21:08,590 Na hivyo muda mrefu kama kompyuta hiyo anajua jinsi ya kubadilisha 468 00:21:08,590 --> 00:21:10,900 umma anwani kwa anuani binafsi, 469 00:21:10,900 --> 00:21:13,340 kila kitu unaweza aina ya kazi kama ilivyotarajiwa. 470 00:21:13,340 --> 00:21:17,290 >> Lakini kinyume cha hili ni kwamba kama uko nyumbani na una ndugu, 471 00:21:17,290 --> 00:21:19,650 na nyote wawili ni kutembelea baadhi ya tovuti, 472 00:21:19,650 --> 00:21:23,520 tovuti hiyo haina kujua kama ni wewe au ndugu yako kutembelea tovuti, 473 00:21:23,520 --> 00:21:26,780 kwa sababu wewe kuonekana kuwa sawa mtu kwa sababu yote ya takwimu yako 474 00:21:26,780 --> 00:21:30,050 ni kwenda kwa kuwa ruta au hatua hiyo ya kati. 475 00:21:30,050 --> 00:21:32,220 >> Lakini kutosha juu ya haya maelezo ngazi ya chini. 476 00:21:32,220 --> 00:21:37,770 Hebu tuangalie jinsi IP anwani wakati mwingine kuja labda katika vyombo vya habari 477 00:21:37,770 --> 00:21:41,370 na jinsi gani tunaweza sasa kuanza uharibifu, kusema ukweli, inaonyesha hata zaidi kwa ajili yenu. 478 00:21:41,370 --> 00:21:45,010 Kama tunaweza dim taa kwa sekunde chache. 479 00:21:45,010 --> 00:21:46,550 >> [VIDEO avspelning] 480 00:21:46,550 --> 00:21:49,310 >> -Ni 32-bit juu ya IPP 4 ya mahali. 481 00:21:49,310 --> 00:21:50,650 >> -IP ES internet-- 482 00:21:50,650 --> 00:21:52,800 >> -Private Mtandao, Tamia binafsi mtandao. 483 00:21:52,800 --> 00:22:05,670 484 00:22:05,670 --> 00:22:08,145 Yeye ni hivyo ajabu. 485 00:22:08,145 --> 00:22:09,630 -Come Juu ya Charlie. 486 00:22:09,630 --> 00:22:11,750 DAVID J. Malan: Ni anuani kioo IP. 487 00:22:11,750 --> 00:22:15,093 Yeye ni kuruhusu sisi kuangalia ambayo yeye anafanya kwa muda muafaka. 488 00:22:15,093 --> 00:22:16,285 >> [Mwisho avspelning] 489 00:22:16,285 --> 00:22:17,130 >> DAVID J. Malan: Sawa. 490 00:22:17,130 --> 00:22:18,480 Matatizo wachache na hili. 491 00:22:18,480 --> 00:22:22,740 Hivyo moja, nini sisi ni kuangalia katika hapa kwenye screen 492 00:22:22,740 --> 00:22:25,290 ni sheria iliyoandikwa katika lugha inayoitwa Lengo-C, 493 00:22:25,290 --> 00:22:28,020 ambayo ni aina ya mrithi wa C lugha kwamba sisi ni kufanya. 494 00:22:28,020 --> 00:22:30,150 Hii ina kitu kabisa cha kufanya na programu. 495 00:22:30,150 --> 00:22:32,399 Kwa kweli, kama bora naweza kukuambia, hii ni kuchora mpango 496 00:22:32,399 --> 00:22:38,360 kwamba mtu kupakuliwa kutoka biashara kwa namna fulani kuwashirikisha crayons. 497 00:22:38,360 --> 00:22:43,660 >> Labda kidogo egregious ni kwamba anwani hii ya IP, halali au batili? 498 00:22:43,660 --> 00:22:44,520 >> Watazamaji: batili. 499 00:22:44,520 --> 00:22:48,479 >> DAVID J. Malan: batili, kwa sababu 275 Ni, bila shaka, si kati ya 0 na 255. 500 00:22:48,479 --> 00:22:51,770 Hiyo pia pengine ni sawa ingawa, kwa sababu wewe hawataki kundi la watu mambo 501 00:22:51,770 --> 00:22:54,790 ambao ni kama pausing TV juu yao TiVos na kisha kutembelea IP kuona 502 00:22:54,790 --> 00:22:56,290 kama kweli kuna kitu huko. 503 00:22:56,290 --> 00:22:58,200 Ili mtu ni kidogo kidogo egregious. 504 00:22:58,200 --> 00:23:00,990 Lakini kutambua kwamba pia ni aina ya karibu nasi. 505 00:23:00,990 --> 00:23:04,980 >> Hivyo bila shaka, hakuna hata mmoja wetu milele kweli aina anwani ya numeric 506 00:23:04,980 --> 00:23:06,410 ndani ya browsers wetu. 507 00:23:06,410 --> 00:23:09,580 Itakuwa aina ya kitu mbaya kama Google, kutembelea Google, 508 00:23:09,580 --> 00:23:15,060 wewe alikuwa na kwenda 123.46.57.89. 509 00:23:15,060 --> 00:23:17,007 Na dunia nzima alikuwa kukumbuka tu. 510 00:23:17,007 --> 00:23:19,090 Na kusema ukweli, tumekuwa aina ya kuonekana suala hili kabla. 511 00:23:19,090 --> 00:23:24,130 Nyuma katika siku wakati watu hawana na simu za kiganjani na orodha ya kuwasiliana, 512 00:23:24,130 --> 00:23:27,640 na makampuni kweli still-- kweli, Nadhani makampuni bado wana 800 513 00:23:27,640 --> 00:23:30,600 idadi na like-- lakini wewe ujumla kuona idadi kutangazwa 514 00:23:30,600 --> 00:23:36,480 kama 1-800-KUKUSANYA, C-O-L-L-E-C-T. Kwa sababu hakuna mtu anayeweza kweli kumbuka, 515 00:23:36,480 --> 00:23:39,754 wakati kuona matangazo kwenye basi au Billboard, nini mtu idadi ni, 516 00:23:39,754 --> 00:23:42,420 lakini wanaweza pengine, na juu uwezekano, kumbuka neno. 517 00:23:42,420 --> 00:23:44,530 >> Hivyo sisi iliyopitishwa sawa aina ya mfumo katika ulimwengu 518 00:23:44,530 --> 00:23:48,290 ya biashara ambapo kuna mfumo jina la uwanja ili tuweze binadamu Unaweza 519 00:23:48,290 --> 00:23:52,340 aina google.com, facebook.com, yale.edu, harvard.edu, 520 00:23:52,340 --> 00:23:56,140 na basi kompyuta takwimu nini IP sambamba 521 00:23:56,140 --> 00:23:58,480 anuani ni kwa jina aliyopewa. 522 00:23:58,480 --> 00:24:01,620 >> Na njia ya kufanya hivyo katika dunia halisi ni kwamba kwa $ 10 kwa mwaka, 523 00:24:01,620 --> 00:24:05,900 labda $ 50 kwa mwaka, unaweza kununua uwanja jina, au kweli kodi jina la uwanja. 524 00:24:05,900 --> 00:24:09,860 Na kisha kila mtu wewe ni kulipa kodi kwamba jina la uwanja, 525 00:24:09,860 --> 00:24:14,069 wewe kuwaambia ambao katika ulimwengu anajua nini anwani yako ya IP ni. 526 00:24:14,069 --> 00:24:16,360 Na sisi si kwenda katika hizo maelezo, lakini wengi wenu 527 00:24:16,360 --> 00:24:18,750 kutaka, kwa fainali miradi, kwa kweli ishara ya juu 528 00:24:18,750 --> 00:24:22,120 kwa ajili ya mtandao yako mwenyewe mwenyeji kampuni hiyo, ama kwa ajili ya bure 529 00:24:22,120 --> 00:24:23,500 au kwa dola chache kwa mwezi. 530 00:24:23,500 --> 00:24:26,100 Baadhi ya unaweza kutaka kununua, kwa dola chache, yako mwenyewe jina la uwanja, 531 00:24:26,100 --> 00:24:28,900 kwa ajili ya kujifurahisha au kuanzisha biashara au tovuti binafsi au kama. 532 00:24:28,900 --> 00:24:30,880 >> Na kutambua kwamba wote ya kwamba mapenzi hatimaye 533 00:24:30,880 --> 00:24:35,260 jipu chini kwa wewe kuwaambia dunia nini server yako IP ni. 534 00:24:35,260 --> 00:24:37,740 Na kisha DNS hizi watumishi kweli utunzaji 535 00:24:37,740 --> 00:24:39,910 ya kuhabarisha wengine wa dunia. 536 00:24:39,910 --> 00:24:41,830 Basi wote DNS server ina, katika muda mfupi, ndani ya 537 00:24:41,830 --> 00:24:44,780 ya kumbukumbu yake ni kama sawa na spreadsheet Google 538 00:24:44,780 --> 00:24:49,420 au Excel spreadsheet na angalau nguzo mbili, moja ambayo ina majina, 539 00:24:49,420 --> 00:24:52,100 kama harvard.edu, na yale.edu, na google.com. 540 00:24:52,100 --> 00:24:55,870 Na safu nyingine ina sambamba IP au IP 541 00:24:55,870 --> 00:24:56,382 anwani. 542 00:24:56,382 --> 00:24:57,590 Na tunaweza kweli kuona hii. 543 00:24:57,590 --> 00:24:59,881 Kadhalika Mac-- yangu na unaweza kufanya hivyo juu ya Windows kompyuta 544 00:24:59,881 --> 00:25:04,330 kama well-- kama mimi kufungua dirisha terminal hapa, kabisa kama moja katika CD50 IDE, 545 00:25:04,330 --> 00:25:08,190 kompyuta nyingi na amri inayoitwa nslookup, jina server kuangalia juu. 546 00:25:08,190 --> 00:25:12,380 Na kama mimi aina kitu katika kama yale.edu na hit Enter, nini 547 00:25:12,380 --> 00:25:19,250 Mimi lazima kuona kama mtandao wangu inashirikiana kama ilivyokuwa kwa vipimo mbalimbali kabla ya darasa 548 00:25:19,250 --> 00:25:24,584 began-- hebu jaribu google.com. 549 00:25:24,584 --> 00:25:26,390 Bila shaka sasa hakuna kitu kazi. 550 00:25:26,390 --> 00:25:27,190 Hiyo ni kubwa. 551 00:25:27,190 --> 00:25:30,660 Sawa, kusimama kwa ajili ya wakati mmoja. 552 00:25:30,660 --> 00:25:32,100 nslookup google.com. 553 00:25:32,100 --> 00:25:35,570 554 00:25:35,570 --> 00:25:38,660 >> Naam, hebu angalia kama halisi internet-- hakuna. 555 00:25:38,660 --> 00:25:39,700 Hiyo ni nini kilichotokea. 556 00:25:39,700 --> 00:25:43,090 Oh mungu wangu, sawa. 557 00:25:43,090 --> 00:25:45,490 Wi-Fi kukatika. 558 00:25:45,490 --> 00:25:47,410 >> Hey, unataka kujua nini anwani yangu ya IP ni? 559 00:25:47,410 --> 00:25:49,722 Sawa. 560 00:25:49,722 --> 00:25:50,820 YaleSecure. 561 00:25:50,820 --> 00:25:53,330 Hii ni jinsi gani troubleshoot mambo kama kompyuta mwanasayansi. 562 00:25:53,330 --> 00:25:54,617 Sisi kugeuka Wi-Fi mbali. 563 00:25:54,617 --> 00:25:57,480 564 00:25:57,480 --> 00:25:59,450 SAWA. 565 00:25:59,450 --> 00:26:02,610 >> Na kwa kweli, Scaz, je, wewe akili magogo yetu katika moja salama? 566 00:26:02,610 --> 00:26:06,246 Vinginevyo vipimo zaidi are-- sawa, kumshukuru wewe Yale-- au ni kuhusu kuvunja. 567 00:26:06,246 --> 00:26:07,370 Nataka kwenda kwenye YaleSecure. 568 00:26:07,370 --> 00:26:09,880 569 00:26:09,880 --> 00:26:11,870 Oh, na labda tutaweza kuwa sawa. 570 00:26:11,870 --> 00:26:12,686 Labda tuko nyuma. 571 00:26:12,686 --> 00:26:16,810 572 00:26:16,810 --> 00:26:19,733 Na kwamba ni jinsi, kama kompyuta Mwanasayansi kurekebisha kompyuta. 573 00:26:19,733 --> 00:26:22,000 [Makofi] 574 00:26:22,000 --> 00:26:23,220 Sawa. 575 00:26:23,220 --> 00:26:27,160 Hivyo ambapo mimi nilikuwa ndani ya hii kinachojulikana terminal dirisha, 576 00:26:27,160 --> 00:26:32,270 na kama mimi nslookup yale.edu, kuna sisi kwenda. 577 00:26:32,270 --> 00:26:38,350 Hivyo mimi kupata nyuma kwanza IP ya DNS server kwamba mbali yangu ni kutumia. 578 00:26:38,350 --> 00:26:41,610 Hivyo kwa kuongeza DHCP server kwamba kuongelea wakati iliyopita kuwaambia 579 00:26:41,610 --> 00:26:44,720 mbali yangu kile IP yangu anuani ni kwamba DHCP server 580 00:26:44,720 --> 00:26:46,860 Pia anasema mimi nini DNS server kutumia. 581 00:26:46,860 --> 00:26:48,860 Vinginevyo mimi ingekuwa aina manually katika hili. 582 00:26:48,860 --> 00:26:50,359 >> Lakini si kwamba wote kwamba kuvutia. 583 00:26:50,359 --> 00:26:54,310 Nini mimi huduma ya juu ni kwamba hii ni IP ya tovuti Yale ya inaonekana. 584 00:26:54,310 --> 00:26:55,470 Hivyo kwa kweli, hebu jaribu hii. 585 00:26:55,470 --> 00:27:02,710 Hebu kwenda juu katika browser na kwenda http: //, na kisha kwamba anwani ya IP, 586 00:27:02,710 --> 00:27:04,220 na hit Enter. 587 00:27:04,220 --> 00:27:06,700 Na tuone. 588 00:27:06,700 --> 00:27:09,587 Hiyo ni jinsi mwingine unaweza kutembelea tovuti Yale ya. 589 00:27:09,587 --> 00:27:10,920 Sasa ni si wote kwamba kukumbukwa. 590 00:27:10,920 --> 00:27:12,220 Kama, kabla ya Frosh pengine si kwenda 591 00:27:12,220 --> 00:27:15,310 kukumbuka anwani hii hasa kama aliiambia kutembelea huko baada ya kutembelea. 592 00:27:15,310 --> 00:27:16,580 Lakini haina wanaonekana kazi. 593 00:27:16,580 --> 00:27:21,179 Na hivyo DNS kweli tu inaruhusu sisi na mengi zaidi anwani ya kirafiki binadamu. 594 00:27:21,179 --> 00:27:23,220 Lakini wao si lazima tu mavuno jibu moja. 595 00:27:23,220 --> 00:27:25,640 >> Kwa kweli, wakati uko kweli kubwa tech, 596 00:27:25,640 --> 00:27:27,620 pengine unataka kuwa na kura ya watumishi. 597 00:27:27,620 --> 00:27:29,027 Na hata hii ni kupotosha. 598 00:27:29,027 --> 00:27:31,110 Hivyo Yale pengine hana kuwa moja tu mtandao wa kompyuta. 599 00:27:31,110 --> 00:27:34,150 Google pengine hana mtandao 10 tu au hivyo watumishi. 600 00:27:34,150 --> 00:27:36,960 Google hasa pengine ina maelfu ya servrar mtandao 601 00:27:36,960 --> 00:27:40,030 duniani kote kwamba anaweza kujibu maombi kutoka kwa watu kama sisi. 602 00:27:40,030 --> 00:27:43,870 >> Lakini pia kutumia teknolojia iitwayo mzigo kusawazisha, ambayo hadithi muda mfupi, 603 00:27:43,870 --> 00:27:48,810 ina tu ya vifaa chache katika dunia kueneza mzigo katika seva zaidi. 604 00:27:48,810 --> 00:27:52,320 Hivyo ni aina ya kama buibui mtandao kama utakuwa kupeleka maombi. 605 00:27:52,320 --> 00:27:54,380 Lakini kwa sasa, yote hiyo ni kuvutia kwa leo 606 00:27:54,380 --> 00:27:56,870 ni kwamba jina la uwanja kama google.com hata Unaweza 607 00:27:56,870 --> 00:28:00,100 na anwani nyingi IP kama hiyo. 608 00:28:00,100 --> 00:28:04,610 >> Lakini jinsi gani yote ya takwimu zetu kweli kupata na kurudi kisha katika mwisho? 609 00:28:04,610 --> 00:28:08,320 Naam, zinageuka kuwa kuna hizi mambo kuitwa ruta kwenye mtandao. 610 00:28:08,320 --> 00:28:10,980 Na ni nini router kwa kiasi kwamba unajua tayari? 611 00:28:10,980 --> 00:28:13,730 Na nimekuwa alitumia neno wanandoa mara katika mazingira ya nyumbani, 612 00:28:13,730 --> 00:28:17,155 lakini kwa maneno rahisi, je ruta nini? 613 00:28:17,155 --> 00:28:18,780 Nipe tu nadhani kulingana na jina lake? 614 00:28:18,780 --> 00:28:20,082 >> Watazamaji: Hivyo barabara au njia? 615 00:28:20,082 --> 00:28:21,790 DAVID J. Malan: Hivyo ni barabara au njia. 616 00:28:21,790 --> 00:28:23,980 Hivyo njia ni barabara au njia, kabisa. 617 00:28:23,980 --> 00:28:27,000 Na router, hivyo kifaa kwamba kweli njia ya habari, 618 00:28:27,000 --> 00:28:29,690 ingekuwa hoja data kati ya pointi na B. 619 00:28:29,690 --> 00:28:31,920 >> Na hivyo katika fact-- na hii ni labda wakati 620 00:28:31,920 --> 00:28:34,510 wewe Google depictions ya ruta juu ya dunia, wote kupata 621 00:28:34,510 --> 00:28:35,900 ni cheesy masoko vielelezo. 622 00:28:35,900 --> 00:28:38,550 Na hivyo hii ni aina ya zaidi mwakilishi mmoja mimi naweza kupata 623 00:28:38,550 --> 00:28:39,841 kwamba inaonekana upole kuvutia. 624 00:28:39,841 --> 00:28:44,170 Kila moja ya nukta hizi au glimmers ya matumaini duniani kote inawakilisha ruta. 625 00:28:44,170 --> 00:28:47,210 Na kila mmoja wao ana mstari kati ya baadhi ruta mengine. 626 00:28:47,210 --> 00:28:49,090 >> Kwa sababu kwa hakika, kuna maelfu, pengine 627 00:28:49,090 --> 00:28:52,560 mamilioni ya ruta karibu dunia, ambayo baadhi ni katika nyumba zetu 628 00:28:52,560 --> 00:28:56,070 na juu ya vyuo vikuu wetu, lakini mengi ya ambayo ni inayomilikiwa na makampuni makubwa 629 00:28:56,070 --> 00:29:00,250 na ni unahusiana ili kwamba kama mimi unataka kutuma baadhi takwimu kutoka hapa katika Yale 630 00:29:00,250 --> 00:29:04,430 kurudi nyumbani kwa Cambridge, Yale pengine hana cable moja, hakika, 631 00:29:04,430 --> 00:29:05,650 kwenda moja kwa moja Harvard. 632 00:29:05,650 --> 00:29:07,399 Na Yale hana cable moja kwenda 633 00:29:07,399 --> 00:29:10,010 kwa MIT, au kwa Stanford, au kwa Berkeley, au kwa Google, 634 00:29:10,010 --> 00:29:11,820 au idadi yoyote ya kivutio. 635 00:29:11,820 --> 00:29:14,760 >> Badala yake, Yale, na Harvard, na kila mtu mwingine kwenye mtandao 636 00:29:14,760 --> 00:29:17,610 gani kuwa ruta moja au zaidi kushikamana na hayo, labda 637 00:29:17,610 --> 00:29:18,810 juu ya pembezoni ya chuo. 638 00:29:18,810 --> 00:29:21,690 Hivyo kwamba wakati data wangu anataka kuondoka chuo cha Yale wa, 639 00:29:21,690 --> 00:29:24,770 unaendelea na kwamba router karibu zaidi, kama taswira na mmoja wa nukta hizi. 640 00:29:24,770 --> 00:29:27,940 Na kisha kwamba router takwimu nje kama kutuma kwa njia hii, au kwa njia hii, 641 00:29:27,940 --> 00:29:33,440 au kwa njia hii, au kwa njia hii kwa kuzingatia juu ya meza nyingine katika kumbukumbu zake, 642 00:29:33,440 --> 00:29:36,870 faili mwingine Excel au Google spreadsheet kwamba katika safu moja 643 00:29:36,870 --> 00:29:41,315 anasema, kama anwani yako ya IP kuanza na namba moja, kwenda njia hii. 644 00:29:41,315 --> 00:29:43,690 Kama anwani yako ya IP huanza na namba mbili, kwenda kwa njia hiyo. 645 00:29:43,690 --> 00:29:47,040 Na hivyo unaweza kuvunja chini numerically kuwa na router kutuma 646 00:29:47,040 --> 00:29:49,040 data kila njia ambayo. 647 00:29:49,040 --> 00:29:51,419 >> Na tunaweza aina ya kuona hii kama vile. 648 00:29:51,419 --> 00:29:54,210 Hebu kwenda mbele katika terminal huu dirisha tena, na basi mimi kwenda mbele 649 00:29:54,210 --> 00:30:00,700 na kuwaeleza njia ya, hebu sema, www.mit.edu, 650 00:30:00,700 --> 00:30:02,970 ambayo ni mia kadhaa maili. 651 00:30:02,970 --> 00:30:04,500 Hiyo ilikuwa ni kweli damn haraka. 652 00:30:04,500 --> 00:30:06,290 >> Kwa hiyo kile tu kilichotokea? 653 00:30:06,290 --> 00:30:10,360 Hivyo katika hatua saba tu, na katika milliseconds nne tu, 654 00:30:10,360 --> 00:30:14,660 Mimi alimtuma data juu ya mtandao kutoka hapa katika Yale kwa MIT. 655 00:30:14,660 --> 00:30:18,240 Kila moja ya safu hizi, unaweza labda nadhani sasa inawakilisha nini? 656 00:30:18,240 --> 00:30:19,060 >> Watazamaji: router. 657 00:30:19,060 --> 00:30:20,101 >> DAVID J. Malan: router. 658 00:30:20,101 --> 00:30:24,090 Hivyo kweli, inaonekana kama kuna miaka saba au hivyo ruta, 659 00:30:24,090 --> 00:30:29,350 au ruta sita katika kati ya mimi kimwili katika shule ya sheria Yale ya hapa 660 00:30:29,350 --> 00:30:31,612 na tovuti MIT zaidi ya hapo. 661 00:30:31,612 --> 00:30:34,570 Na nini tunaweza kubariki kutoka hii ni kama follows-- na napenda safi it up. 662 00:30:34,570 --> 00:30:38,180 Mimi nina kwenda rerun yake na amri mstari hoja ya -q 1 kwa kusema tu, 663 00:30:38,180 --> 00:30:39,300 nipe tu swala moja. 664 00:30:39,300 --> 00:30:40,800 By default, kuwaeleza njia gani tatu. 665 00:30:40,800 --> 00:30:42,350 Na hii ndiyo maana tuliona mashada ya namba. 666 00:30:42,350 --> 00:30:44,850 Nataka kuona idadi wachache tu kuweka pato safi. 667 00:30:44,850 --> 00:30:46,280 Na hebu angalia nini kinatokea. 668 00:30:46,280 --> 00:30:49,220 >> Hivyo kwa sababu yoyote, mtu katika Yale mawazo 669 00:30:49,220 --> 00:30:54,130 itakuwa funny kuiita yako chaguo-msingi router arubacentral, ambayo 670 00:30:54,130 --> 00:30:57,920 ni juu ya VLAN au virtual LAN, virtual wa eneo 671 00:30:57,920 --> 00:30:59,810 mtandao 30-- hivyo pengine kuwa na angalau 672 00:30:59,810 --> 00:31:03,050 29 others-- router.net.yale.internal. 673 00:31:03,050 --> 00:31:06,660 Na .internal hapa ni aina ya bandia ngazi ya juu ya uwanja maana ya kutumika tu 674 00:31:06,660 --> 00:31:07,210 juu ya chuo. 675 00:31:07,210 --> 00:31:10,335 Na taarifa IP sambamba ya kwamba router, popote ni hapa 676 00:31:10,335 --> 00:31:13,920 juu ya chuo, ni 172.28.204.129. 677 00:31:13,920 --> 00:31:17,470 Na ilichukua 36 milliseconds kwenda kutoka hapa hadi pale. 678 00:31:17,470 --> 00:31:18,050 >> Mapenzi hadithi. 679 00:31:18,050 --> 00:31:19,716 Tutaweza kupata nyuma na kwamba katika muda tu. 680 00:31:19,716 --> 00:31:22,920 Lakini sasa pili router-- kwa ambayo inaonekana arubacentral 681 00:31:22,920 --> 00:31:25,790 ina aina fulani ya kimwili uhusiano zaidi likely-- 682 00:31:25,790 --> 00:31:27,249 binadamu haikujali kumtaja yake. 683 00:31:27,249 --> 00:31:30,373 Binadamu Yale haikujali kumtaja ni kwa sababu ni ndani ya mtandao wako 684 00:31:30,373 --> 00:31:30,940 Inaonekana. 685 00:31:30,940 --> 00:31:32,520 Na hivyo tu ana IP. 686 00:31:32,520 --> 00:31:34,660 >> Lakini basi ruta tatu hapa kwenye mtandao Yale ya 687 00:31:34,660 --> 00:31:36,700 kwamba pengine kidogo mbali mbali bado 688 00:31:36,700 --> 00:31:41,330 inaitwa cen10g chochote kuwa ni asr.net.yale.internal. 689 00:31:41,330 --> 00:31:43,040 Na pia ina anwani ya IP. 690 00:31:43,040 --> 00:31:44,990 >> Sasa kwa nini ni namba hizi aina ya kushuka? 691 00:31:44,990 --> 00:31:47,890 2.9, 1.4, 36? 692 00:31:47,890 --> 00:31:48,840 Ruta kupata busy. 693 00:31:48,840 --> 00:31:50,420 Na wao kupata msongamano na yanayoambatana. 694 00:31:50,420 --> 00:31:53,200 Kuna maelfu ya watu juu ya hii chuo kwa kutumia mtandao kwa sasa. 695 00:31:53,200 --> 00:31:56,050 Kuna mia watu katika hii chumba kwa kutumia mtandao kwa sasa. 696 00:31:56,050 --> 00:31:59,030 >> Na hivyo nini kinatokea ni kwamba ruta ili kupata msongamano. 697 00:31:59,030 --> 00:32:01,350 Na hivyo nyakati hizo nguvu fluctuate kidogo. 698 00:32:01,350 --> 00:32:04,620 Hivyo ndiyo sababu wao si lazima kuongeza straightforwardly. 699 00:32:04,620 --> 00:32:07,510 >> Lakini mambo kupata aina ya kuvutia katika hatua nne. 700 00:32:07,510 --> 00:32:13,040 Inavyoonekana kati ya Yale na hatua nne ni hop mwingine. 701 00:32:13,040 --> 00:32:16,480 Na ambapo ni router katika hatua nne pengine? 702 00:32:16,480 --> 00:32:17,410 >> Watazamaji: [inaudible] 703 00:32:17,410 --> 00:32:19,410 >> DAVID J. Malan: JFK labda, labda katika uwanja wa ndege. 704 00:32:19,410 --> 00:32:21,950 Lakini kwa sababu yoyote, mfumo wa watawala, ili 705 00:32:21,950 --> 00:32:24,140 geeks kwamba kukimbia watumishi kwa Miaka yapanga ruta 706 00:32:24,140 --> 00:32:25,600 baada ya karibu na uwanja wa ndege kificho. 707 00:32:25,600 --> 00:32:27,420 Hivyo JFK pengine maana yake ni ni tu mahali fulani 708 00:32:27,420 --> 00:32:29,970 mjini New York, labda katika Manhattan au mmoja wa mabasi. 709 00:32:29,970 --> 00:32:34,460 nyc2 inaashiria, labda, mwingine ruta hiyo ni mahali fulani katika New York. 710 00:32:34,460 --> 00:32:37,140 >> Sijui kabisa kujua wapi mstari sita ni hapa, ruta idadi sita. 711 00:32:37,140 --> 00:32:40,110 quest.net ISP kubwa, mtoa huduma ya internet, 712 00:32:40,110 --> 00:32:43,240 ambayo hutoa kuunganishwa mtandao kwa maeneo makubwa kama Yale na wengine. 713 00:32:43,240 --> 00:32:47,110 Na kisha hii moja iliyopita, ni Inaonekana kama kwamba MIT haina hata 714 00:32:47,110 --> 00:32:50,180 kuwa na tovuti zao wenyewe Cambridge lazima, 715 00:32:50,180 --> 00:32:52,090 bali wameweza outsourced tovuti yao, 716 00:32:52,090 --> 00:32:55,150 au angalau watumishi wa kimwili, kwa kampuni inayoitwa Akamai. 717 00:32:55,150 --> 00:32:57,940 Na Akamai kweli ni haki ya chini barabara kutoka MIT katika Cambridge 718 00:32:57,940 --> 00:32:58,790 ni zamu nje. 719 00:32:58,790 --> 00:33:02,360 >> Lakini kutambua pia kwamba hata mawazo wewe ni kwenda www.mit.edu, 720 00:33:02,360 --> 00:33:05,200 sisi inaweza kweli kutumwa mahali popote duniani. 721 00:33:05,200 --> 00:33:06,960 >> Na hebu angalia mahali fulani popote duniani. 722 00:33:06,960 --> 00:33:09,240 Hebu kwenda mbele na wazi screen hii na badala yake 723 00:33:09,240 --> 00:33:15,240 kuwaeleza njia, mara moja tu, hivyo swala moja, kwa www.cnn.co.jp, 724 00:33:15,240 --> 00:33:18,390 ukurasa Japan nyumbani kwa CNN, habari tovuti. 725 00:33:18,390 --> 00:33:20,660 Na kama mimi hit Enter sasa, hebu angalia nini kinatokea. 726 00:33:20,660 --> 00:33:23,610 Sisi ni tena kuanzia saa arubacentral. 727 00:33:23,610 --> 00:33:26,510 Sisi ni kisha kwenda Nameless ruta, chache zaidi. 728 00:33:26,510 --> 00:33:29,527 Hivyo alichukua humle 12 kwa kupata Japan wakati huu. 729 00:33:29,527 --> 00:33:30,860 Na hebu angalia nini tunaweza kubariki. 730 00:33:30,860 --> 00:33:32,450 >> Hop hivyo huo, hop huo. 731 00:33:32,450 --> 00:33:35,170 Tofauti kidogo sasa. 732 00:33:35,170 --> 00:33:36,380 Hii moja ya kuvutia. 733 00:33:36,380 --> 00:33:40,870 Hivyo mimi nina kubahatisha hapa, stamford1 ni miji chache tu katika Connecticut pia. 734 00:33:40,870 --> 00:33:43,810 Hizi ruta mfululizo sita na saba hawana majina. 735 00:33:43,810 --> 00:33:46,370 Lakini hii ni aina ya ajabu. 736 00:33:46,370 --> 00:33:53,310 >> Kwa hiyo kile inaonekana kuwa kati ya ruta katika hatua saba na nane? 737 00:33:53,310 --> 00:33:54,760 Na kwa nini kusema kama kiasi? 738 00:33:54,760 --> 00:33:55,260 Yeah? 739 00:33:55,260 --> 00:33:56,060 >> Watazamaji: Ocean. 740 00:33:56,060 --> 00:33:57,640 >> DAVID J. Malan: Pengine bahari. 741 00:33:57,640 --> 00:34:01,366 Tunajua kwamba kweli kama, shirikishi, sawa? 742 00:34:01,366 --> 00:34:04,790 Lakini tunaweza kuthibitisha aina kama kiasi ya aina ya empirically kwa nini? 743 00:34:04,790 --> 00:34:06,860 Nini kimebadilika kati ya safu saba na nane? 744 00:34:06,860 --> 00:34:09,429 745 00:34:09,429 --> 00:34:14,739 >> Ilichukua muda mwingi zaidi wa kwenda chochote hii router Nameless saba ni, 746 00:34:14,739 --> 00:34:18,670 pengine mahali fulani katika Marekani bara, hatua nane, 747 00:34:18,670 --> 00:34:22,639 ambayo pengine ni mahali fulani katika Japan kulingana na jina la uwanja wa .jp huko. 748 00:34:22,639 --> 00:34:25,719 Na hivyo wale ziada mia kitu milliseconds 749 00:34:25,719 --> 00:34:28,960 au 90 au hivyo milliseconds ni Kutokana na takwimu zetu kwenda 750 00:34:28,960 --> 00:34:31,100 juu ya mwili mzuri kikubwa cha maji. 751 00:34:31,100 --> 00:34:34,570 >> Sasa ajabu, inaonekana kwamba labda kwamba cable huenda hela Marekani nzima. 752 00:34:34,570 --> 00:34:37,070 Kama sisi ni kweli kwenda juu ya West Coast kupata Japan, 753 00:34:37,070 --> 00:34:39,111 ni aina ya njia ya muda mrefu kama sisi kwenda njia nyingine. 754 00:34:39,111 --> 00:34:41,400 Hivyo ni si wazi kabisa nini kinaendelea kimwili. 755 00:34:41,400 --> 00:34:43,830 Lakini ukweli kwamba kila hop ya ziada hakika 756 00:34:43,830 --> 00:34:46,020 alichukua walikotoka tena kuliko kila mengine, ni 757 00:34:46,020 --> 00:34:50,440 nzuri uthibitisho kwamba CNN Japan mtandao wa kompyuta pengine ni kweli 758 00:34:50,440 --> 00:34:51,310 nchini Japan. 759 00:34:51,310 --> 00:34:54,089 Na ni hakika mbali mbali zaidi kuliko MIT imekuwa. 760 00:34:54,089 --> 00:34:56,380 Na ni thamani kubainisha pia, data zako ni si lazima 761 00:34:56,380 --> 00:34:58,794 kwenda kusafiri mfupi iwezekanavyo umbali. 762 00:34:58,794 --> 00:35:00,960 Kwa kweli, kama wewe kucheza karibu kwa kuwaeleza njia nyumbani 763 00:35:00,960 --> 00:35:04,170 tu kuokota tovuti random, wewe kupata kwamba tu kutuma barua pepe 764 00:35:04,170 --> 00:35:06,490 au kutembelea tovuti hiyo ni hapa katika New Haven, 765 00:35:06,490 --> 00:35:09,200 wakati mwingine data yako wapate kwanza kuchukua detour, kwenda chini kwa DC, 766 00:35:09,200 --> 00:35:10,450 na kisha kuja nyuma juu. 767 00:35:10,450 --> 00:35:12,860 Na hiyo ndiyo sababu tu ya maamuzi routing nguvu 768 00:35:12,860 --> 00:35:14,650 kwamba kompyuta hizi ni maamuzi. 769 00:35:14,650 --> 00:35:18,930 >> Sasa kwa ajili ya kujifurahisha, timu ya uzalishaji trimmed moja ya video hizo kwa ajili yetu 770 00:35:18,930 --> 00:35:20,807 tu kuwa kidogo zaidi succinct. 771 00:35:20,807 --> 00:35:23,640 Lakini kutupa hisia ya haraka here-- na tunaweza kuondoka taa on-- 772 00:35:23,640 --> 00:35:32,363 kama tu jinsi gani ni cabling kweli kufanya yote ya takwimu zetu. 773 00:35:32,363 --> 00:35:33,029 [VIDEO avspelning] 774 00:35:33,029 --> 00:35:36,023 [Music kucheza] 775 00:35:36,023 --> 00:36:31,911 776 00:36:31,911 --> 00:36:32,777 [Mwisho avspelning] 777 00:36:32,777 --> 00:36:35,860 DAVID J. Malan: Video zote mitandao na sounding muziki baridi inaonekana. 778 00:36:35,860 --> 00:36:38,084 Hivyo hiyo ni kupata tu hisia ya ni kiasi gani na 779 00:36:38,084 --> 00:36:39,500 wamekuwa kinachoendelea chini ya Hood. 780 00:36:39,500 --> 00:36:41,355 >> Lakini hebu tuangalie kiwango cha chini kidogo sasa 781 00:36:41,355 --> 00:36:44,150 nini data ni kweli apitaye wale mistari, 782 00:36:44,150 --> 00:36:46,720 na hata kwenda wirelessly katika chumba kama hii. 783 00:36:46,720 --> 00:36:49,580 >> Hivyo ni zamu nje wakati ombi ukurasa wa mtandao, au kutuma barua pepe, 784 00:36:49,580 --> 00:36:53,670 au kupokea ukurasa wa mtandao, au barua pepe, au Ujumbe Gchat, au ujumbe Facebook, 785 00:36:53,670 --> 00:36:57,800 au kama, kwamba si moja tu chunk kubwa ya vipande inapita wirelessly 786 00:36:57,800 --> 00:37:00,600 njia ya hewa au umeme kwenye waya. 787 00:37:00,600 --> 00:37:03,680 Badala yake, ombi hilo au majibu kwa ujumla 788 00:37:03,680 --> 00:37:05,810 chunked juu katika vipande tofauti. 789 00:37:05,810 --> 00:37:08,880 >> Hivyo kwa maneno mengine, wakati una kuomba kufanya ya kompyuta nyingine, 790 00:37:08,880 --> 00:37:10,980 au kupata nyuma majibu kutoka computer-- nyingine 791 00:37:10,980 --> 00:37:15,800 kama tuseme, kwa mfano, kama unfamiliar-- kama watu wengi mno 792 00:37:15,800 --> 00:37:18,400 kuonekana kuwa days-- hizi kama usio wa kawaida na Haya 793 00:37:18,400 --> 00:37:20,200 si hii fellow-- huyu. 794 00:37:20,200 --> 00:37:23,950 Hivyo tuseme hii ni ujumbe kwamba Nataka kupeleka kwa mtu katika nyuma. 795 00:37:23,950 --> 00:37:28,930 Ambao katika sana nyuma wangependa kupokea picha ya Rick Astley leo? 796 00:37:28,930 --> 00:37:29,805 OK, nini jina lako? 797 00:37:29,805 --> 00:37:30,590 >> Watazamaji: Cole. 798 00:37:30,590 --> 00:37:31,306 >> DAVID J. Malan: Ni kitu gani? 799 00:37:31,306 --> 00:37:31,672 >> Watazamaji: Cole. 800 00:37:31,672 --> 00:37:32,040 >> DAVID J. Malan: Holt? 801 00:37:32,040 --> 00:37:32,540 H-O? 802 00:37:32,540 --> 00:37:33,711 Watazamaji: C-O-L-E. 803 00:37:33,711 --> 00:37:34,960 DAVID J. Malan: C-O-L-E, Cole. 804 00:37:34,960 --> 00:37:35,520 Pole. 805 00:37:35,520 --> 00:37:36,430 C-O-L-E. 806 00:37:36,430 --> 00:37:36,930 Sawa. 807 00:37:36,930 --> 00:37:40,990 Hivyo kama nataka kutuma Cole hii picha hapa, unajua hii 808 00:37:40,990 --> 00:37:42,410 ni aina ya picha kubwa, sawa? 809 00:37:42,410 --> 00:37:44,472 Hii inaweza kuwa chache kilobytes, megabytes chache, 810 00:37:44,472 --> 00:37:45,930 hasa kama ni azimio juu. 811 00:37:45,930 --> 00:37:48,660 Na mimi si kweli unataka kuacha kila mtu mwingine kutoka kutumia mtandao 812 00:37:48,660 --> 00:37:50,680 tu wakati mimi kutuma kweli hii kubwa, ubora wa juu picha 813 00:37:50,680 --> 00:37:52,138 ya Rick Astley katika chumba. 814 00:37:52,138 --> 00:37:55,310 Ningependa data yako ya kuendelea traverse mtandao na Wi-Fi 815 00:37:55,310 --> 00:37:56,100 vilevile. 816 00:37:56,100 --> 00:38:00,100 >> Na hivyo inafanya sense-- na hii ni recoverable umeme, 817 00:38:00,100 --> 00:38:01,780 si sana katika ulimwengu wa kweli. 818 00:38:01,780 --> 00:38:04,904 Kwa kweli, hii ni kwenda na nyingi Maana kama wewe kuchukua redio yangu nje. 819 00:38:04,904 --> 00:38:08,360 Hivyo kama mimi machozi huu katika nusu kama hii hapa, 820 00:38:08,360 --> 00:38:11,912 huu sasa wanaweza kusafiri biashara kwa ufanisi zaidi, 821 00:38:11,912 --> 00:38:13,120 kwa sababu ni kipande ndogo. 822 00:38:13,120 --> 00:38:16,780 Hivyo, pamoja na uwezekano wa chini ni kwenda collide na trafiki mtu mwingine 823 00:38:16,780 --> 00:38:17,650 kwenye mtandao. 824 00:38:17,650 --> 00:38:21,240 >> Na hivyo kile kompyuta yako kweli anafanya wakati unataka kutuma ujumbe kwa Cole 825 00:38:21,240 --> 00:38:24,917 je, ni bonge up ujumbe kama huu katika vipande vidogo vidogo, vipande hivyo kusema. 826 00:38:24,917 --> 00:38:28,000 Na kisha unaweka yao ndani ya kile tutaweza wito aina ya bahasha virtual. 827 00:38:28,000 --> 00:38:29,620 >> Hivyo nina bahasha karatasi nne hapa. 828 00:38:29,620 --> 00:38:32,690 Na nimekuwa kabla ya kuhesabiwa kwao, moja, mbili, tatu, na nne. 829 00:38:32,690 --> 00:38:35,800 Na kile Mimi naenda kufanya juu ya mbele ya hii, tu kama barua ya kawaida, 830 00:38:35,800 --> 00:38:38,000 ni mimi nina kwenda kuweka jina Cole huko. 831 00:38:38,000 --> 00:38:41,270 Na kisha juu, mimi nina kwenda kuweka jina langu huko, 832 00:38:41,270 --> 00:38:44,995 Daudi, ili kwanza pakiti kama Mimi kutuma nje huko kwenye mtandao 833 00:38:44,995 --> 00:38:47,620 inaonekana kitu kidogo kama huu, sifa salient 834 00:38:47,620 --> 00:38:50,830 ambao ni kwamba ina kushughulikia, a kutoka mitaani, 835 00:38:50,830 --> 00:38:52,670 na pia idadi, hivyo kuwa kwamba hopefully 836 00:38:52,670 --> 00:38:55,680 ni taarifa za kutosha kwa Cole upya ujumbe huu. 837 00:38:55,680 --> 00:38:58,820 >> Hivyo basi mimi kufanya hivyo hapa, sawa hapa, na huo hapa, 838 00:38:58,820 --> 00:39:01,310 kuandika jina lake katika Karibu na shamba juu yao wote. 839 00:39:01,310 --> 00:39:04,240 Na kisha hebu kwenda mbele na kuweka picha hizi ndani. 840 00:39:04,240 --> 00:39:06,540 >> Hivyo hapa ni pakiti moja hiyo ni tayari kwenda. 841 00:39:06,540 --> 00:39:09,780 Hapa ni pakiti nyingine hiyo ni tayari kwenda. 842 00:39:09,780 --> 00:39:14,100 Hapa ni pakiti tatu hiyo ni tayari kwenda. 843 00:39:14,100 --> 00:39:16,870 Na hapa ni nne pakiti hiyo ni tayari kwenda. 844 00:39:16,870 --> 00:39:19,849 >> Na sasa nini kuvutia kuhusu jinsi biashara katika matendo ukweli 845 00:39:19,849 --> 00:39:22,140 ni kwamba hata kama mimi nimepata pakiti nne, ambayo yote 846 00:39:22,140 --> 00:39:24,730 ni zinazopelekwa kwa moja eneo, wao siyo lazima 847 00:39:24,730 --> 00:39:26,870 kwenda traverse njia hiyo hiyo. 848 00:39:26,870 --> 00:39:32,070 Na hivyo hata kama mimi ili mkono hizi pakiti mbali na router karibu zaidi ya 849 00:39:32,070 --> 00:39:36,660 hebu sema, ikiwa ungependa kuwatuma kwa kila namna, hebu angalia 850 00:39:36,660 --> 00:39:40,706 nini hasa kinatokea, lengo la ambayo ni kupata yao hatimaye Cole. 851 00:39:40,706 --> 00:39:44,850 852 00:39:44,850 --> 00:39:48,770 Na hakika, wao uko tayari si lazima kuchukua mwelekeo huo. 853 00:39:48,770 --> 00:39:50,510 Na hiyo ni nzuri. 854 00:39:50,510 --> 00:39:52,480 Hii ni kidogo Awkward na Oprah style leo. 855 00:39:52,480 --> 00:39:56,540 >> Na sasa napenda makusudi kuchukua kwamba moja nyuma. 856 00:39:56,540 --> 00:40:00,196 Na sasa Cole, kama Ningependa kwa kuiunganisha kama bora unaweza. 857 00:40:00,196 --> 00:40:06,610 858 00:40:06,610 --> 00:40:10,180 Bila shaka, sisi wote nadhani nini hitimisho hapa ni kwenda kuwa. 859 00:40:10,180 --> 00:40:12,600 Wewe ni kwenda na 3/4 ya Rick Astley katika muda tu. 860 00:40:12,600 --> 00:40:15,920 861 00:40:15,920 --> 00:40:19,291 Na nini ingawa ni maana ya kwamba? 862 00:40:19,291 --> 00:40:20,540 Unataka kujaribu kushikilia it up? 863 00:40:20,540 --> 00:40:23,540 Hatuwezi kuwa na kamera moja alisema katika wewe kama Ningependa 864 00:40:23,540 --> 00:40:26,226 pose kwa Rick Astley zaidi ya hapa. 865 00:40:26,226 --> 00:40:28,610 866 00:40:28,610 --> 00:40:29,510 Kuna sisi kwenda. 867 00:40:29,510 --> 00:40:30,410 Nzuri. 868 00:40:30,410 --> 00:40:33,230 >> Lakini wewe wanaonekana kuwa kukosa kipande cha Rick Astley. 869 00:40:33,230 --> 00:40:37,015 Hivyo zinageuka kuwa biashara Kwa ujumla inaendeshwa na si tu IP, 870 00:40:37,015 --> 00:40:39,890 lakini kwa kweli tumesikia katika sana mwanzo wa hotuba katika kwamba video-- 871 00:40:39,890 --> 00:40:42,473 na ve pengine kuona hii kifupi zaidi often-- nini kweli 872 00:40:42,473 --> 00:40:44,360 ni itifaki wewe huwa na kusikia habari zake? 873 00:40:44,360 --> 00:40:45,120 >> Watazamaji: TCP / IP. 874 00:40:45,120 --> 00:40:48,090 >> DAVID J. Malan: TCP / IP, ambayo ni haki mchanganyiko 875 00:40:48,090 --> 00:40:49,940 ya itifaki mbili, moja inaitwa IP. 876 00:40:49,940 --> 00:40:52,640 Ambayo tena, ni tu kuweka ya mikataba kupitia ambayo sisi 877 00:40:52,640 --> 00:40:54,740 kushughulikia kila kompyuta katika mtandao. 878 00:40:54,740 --> 00:40:56,930 Na kisha TCP, ambayo mtumishi lengo jingine. 879 00:40:56,930 --> 00:41:00,110 >> TCP ni itifaki ambayo wewe kawaida kutumia kwa kushirikiana 880 00:41:00,110 --> 00:41:04,410 na IP, kwamba miongoni mwa mengine mambo, utoaji dhamana. 881 00:41:04,410 --> 00:41:08,860 Kwa kweli, TCP itifaki ambayo ni atagundua kuwa moja ya pakiti 882 00:41:08,860 --> 00:41:10,930 inaonekana hakuwa na kupata Cole, kwa sababu yeye inaonekana 883 00:41:10,930 --> 00:41:12,830 kuwa kukosa idadi wanne kati ya nne. 884 00:41:12,830 --> 00:41:16,530 Na hivyo kile TCP, itifaki hivyo, je, ni anaelezea Cole, 885 00:41:16,530 --> 00:41:19,850 hey Cole, kama wewe kupokea tu watatu kati ya pakiti nne, 886 00:41:19,850 --> 00:41:22,600 kuniambia ambayo moja wewe hawajulikani walipo, kimsingi, 887 00:41:22,600 --> 00:41:25,570 na kisha kusudi langu katika maisha lazima retransmit hiyo. 888 00:41:25,570 --> 00:41:28,580 >> Na hivyo kama mimi pia, mtumaji, ni kutumia TCP, 889 00:41:28,580 --> 00:41:31,810 Mimi lazima kisha kuunda packet-- mpya huyu si wrinkled here-- moja 890 00:41:31,810 --> 00:41:35,980 retransmit tu kipande cha hivyo, ili hatimaye Cole ina 891 00:41:35,980 --> 00:41:38,280 souvenir kamili, kama kitu kingine. 892 00:41:38,280 --> 00:41:43,000 Lakini ili hatimaye data kweli anapata wake marudio sahihi. 893 00:41:43,000 --> 00:41:48,020 >> Lakini kwa bahati mbaya, kuandika jina Cole mbele hautoshi, per se. 894 00:41:48,020 --> 00:41:50,270 Na kwa kweli, sipendi kufanya hivyo Jina Cole, lakini pengine 895 00:41:50,270 --> 00:41:51,655 hotuba yake IP juu ya bahasha. 896 00:41:51,655 --> 00:41:52,780 Na sipendi kufanya hivyo Daudi. 897 00:41:52,780 --> 00:41:56,550 Ningependa kuandika anwani yangu ya IP juu ya bahasha ili kompyuta Unaweza kweli 898 00:41:56,550 --> 00:41:57,999 kuwasiliana na kurudi. 899 00:41:57,999 --> 00:42:00,540 Lakini zinageuka kuwa kompyuta anaweza kufanya njia zaidi ya kumtumikia up 900 00:42:00,540 --> 00:42:01,900 picha za Rick Astley. 901 00:42:01,900 --> 00:42:05,340 Wanaweza pia kutuma upya na kupokea barua pepe, ujumbe wa gumzo. 902 00:42:05,340 --> 00:42:09,780 Wanaweza kufanya mambo kama uhamishaji wa faili, na idadi yoyote ya zana nyingine 903 00:42:09,780 --> 00:42:12,330 matumizi kwenye mtandao, watumishi wanaweza kufanya siku hizi. 904 00:42:12,330 --> 00:42:15,300 >> Na kwa sababu tu kampuni hiyo, au shule, au mtu 905 00:42:15,300 --> 00:42:19,420 anataka kuwa na mtandao wa kompyuta, na email server, na mazungumzo server, 906 00:42:19,420 --> 00:42:21,420 haina maana unahitaji kompyuta tatu. 907 00:42:21,420 --> 00:42:26,200 Unaweza kuwa moja tu kompyuta mbio huduma mbalimbali, hivyo kusema. 908 00:42:26,200 --> 00:42:29,190 >> Na hivyo wakati Cole anapata Ujumbe kama hicho, jinsi 909 00:42:29,190 --> 00:42:32,940 haina kompyuta yake kujua kama kuonyesha picha kwamba katika browser yake, 910 00:42:32,940 --> 00:42:37,730 au katika Gchat, au katika Facebook Mtume, au katika idadi yoyote ya zana nyingine? 911 00:42:37,730 --> 00:42:40,430 >> Hivyo ni zamu nje pia juu ya kwamba kama bahasha ni kipande ziada 912 00:42:40,430 --> 00:42:43,070 wa habari inajulikana kama idadi ya bandari. 913 00:42:43,070 --> 00:42:45,240 Na idadi bandari ni idadi tu kwa kweli, 914 00:42:45,240 --> 00:42:48,342 lakini kipekee kubainisha si kompyuta, lakini huduma. 915 00:42:48,342 --> 00:42:49,550 Na kuna mashada ya haya. 916 00:42:49,550 --> 00:42:51,258 Hivyo zinageuka kuwa katika dunia, binadamu 917 00:42:51,258 --> 00:42:57,095 kuamua juu kama chache makongamano, baadhi yake ni haya. 918 00:42:57,095 --> 00:42:59,220 Hivyo kuna kitu kinachoitwa Faili Transfer Itifaki. 919 00:42:59,220 --> 00:42:59,870 Ni pretty tarehe. 920 00:42:59,870 --> 00:43:00,970 Ni salama kabisa. 921 00:43:00,970 --> 00:43:02,320 Mengi ya watu bado matumizi yake. 922 00:43:02,320 --> 00:43:04,240 Na inatumia bandari namba 21. 923 00:43:04,240 --> 00:43:07,250 Kwa maneno mengine, kama kutuma file kupitia FTP, 924 00:43:07,250 --> 00:43:10,570 bahasha ingekuwa si tu msemaji na mpokeaji IP, 925 00:43:10,570 --> 00:43:14,020 ingekuwa pia kuwa na idadi 21 ili kompyuta kupokea anajua loo, hii 926 00:43:14,020 --> 00:43:17,280 ni faili, si barua pepe au ujumbe mazungumzo. 927 00:43:17,280 --> 00:43:19,016 >> 25 ni SMTP. 928 00:43:19,016 --> 00:43:20,516 Ni wangapi wenu wamewahi kutumia SMTP? 929 00:43:20,516 --> 00:43:22,850 930 00:43:22,850 --> 00:43:23,380 Vibaya. 931 00:43:23,380 --> 00:43:24,490 Karibu wote wa wewe. 932 00:43:24,490 --> 00:43:28,730 Kama wameweza milele kutumika email, umetumia SMTP, rahisi barua pepe uhamisho itifaki, 933 00:43:28,730 --> 00:43:32,300 ambayo ni njia tu ya dhana ya kusema, hii ni aina ya kompyuta au huduma 934 00:43:32,300 --> 00:43:34,600 anaye barua pepe utlandet yako. 935 00:43:34,600 --> 00:43:38,780 >> Na kama wameweza milele kuonekana kama Vifupisho POP, au IMAP, na kuna wengine wachache, 936 00:43:38,780 --> 00:43:40,670 wale ni kwa ajili ya kupokea barua pepe, kawaida. 937 00:43:40,670 --> 00:43:42,650 Hiyo ina maana tu ni huduma mbalimbali. 938 00:43:42,650 --> 00:43:45,850 Ni programu ambayo mtu aliandika anaye kwenda au anasikiliza 939 00:43:45,850 --> 00:43:48,880 juu ya bandari maalum idadi hiyo kuwa haina kuwachanganya barua pepe 940 00:43:48,880 --> 00:43:50,360 pamoja na baadhi ya aina nyingine ya data. 941 00:43:50,360 --> 00:43:55,500 >> Sasa mtandao ni HTTP, ambayo ni idadi ya 80, na pia bandari 443. 942 00:43:55,500 --> 00:43:57,590 Na kwa kweli, hata kama sisi binadamu bahati nzuri 943 00:43:57,590 --> 00:43:59,610 Si lazima kufanya hivyo, wakati wowote wewe kutembelea 944 00:43:59,610 --> 00:44:05,810 tovuti kama http://www.yale.edu, browser 945 00:44:05,810 --> 00:44:07,790 ni tu kuwa aina ya kusaidia katika kwamba ni 946 00:44:07,790 --> 00:44:10,970 kuchukua kwamba unataka numeric bandari 80. 947 00:44:10,970 --> 00:44:15,710 Sisi tayari kujua kwamba DNS unaweza kufikiri nini anwani ya IP ni ya www.yale.edu. 948 00:44:15,710 --> 00:44:17,970 Lakini kompyuta ni tu kwenda kudai kuwa wewe 949 00:44:17,970 --> 00:44:21,560 wanataka bandari 80 kwa sababu unatumia Chrome, au IE, au baadhi browser nyingine. 950 00:44:21,560 --> 00:44:24,930 Lakini mimi naweza kitaalam kufanya matumbo 80. 951 00:44:24,930 --> 00:44:28,520 Na kisha siwezi kupanga kuwaambia browser yangu, kutuma pakiti au zaidi 952 00:44:28,520 --> 00:44:32,080 cha habari kwa www.yale.edu kuomba ukurasa wa nyumbani leo. 953 00:44:32,080 --> 00:44:36,070 Lakini hasa, anwani kwa Yale ya IP katika bandari 80 954 00:44:36,070 --> 00:44:39,190 ili niweze kweli kupata kuunga Yale ya mtandao wa kompyuta. 955 00:44:39,190 --> 00:44:42,229 >> Sasa ni mara moja kutoweka kwa sababu browsers tu 956 00:44:42,229 --> 00:44:44,020 kuamua kwamba hatufanyi haja kwa kuwachanganya binadamu 957 00:44:44,020 --> 00:44:46,810 kwa kuwa bado zaidi arcane habari kama koloni 80. 958 00:44:46,810 --> 00:44:50,640 Na kusema ukweli, browsers kama Chrome hawana hata 959 00:44:50,640 --> 00:44:55,464 kuonyesha http tena, au matumbo, au kufyeka kufyeka, au trailing kufyeka, 960 00:44:55,464 --> 00:44:58,380 katika baadhi ya hisia kwa sababu wao ni kujaribu kufanya mambo rahisi kwa watumiaji. 961 00:44:58,380 --> 00:45:01,080 Kwa maana nyingine, ni tu aina uzoefu wa mtumiaji thing-- 962 00:45:01,080 --> 00:45:02,720 hebu kujikwamua baadhi ya clutter. 963 00:45:02,720 --> 00:45:05,405 Lakini ni mafichoni baadhi ya hizi maelezo ya msingi. 964 00:45:05,405 --> 00:45:09,360 >> Na kwa kweli, hakuna hata mmoja wetu pengine milele aina http tena. 965 00:45:09,360 --> 00:45:12,060 Wewe tu aina katika kitu kama www.harvard.edu. 966 00:45:12,060 --> 00:45:15,310 Na tena, infers Chrome kwamba unataka HTTP. 967 00:45:15,310 --> 00:45:18,970 Lakini kuna itifaki nyingine kwamba tunaweza shaka kuwa kutumia. 968 00:45:18,970 --> 00:45:24,480 >> Hivyo kutokana na yote haya, kama wewe sasa aina ya kuvaa kinachojulikana uhandisi kofia, 969 00:45:24,480 --> 00:45:27,417 jinsi gani mambo kuitwa firewalls kazi? 970 00:45:27,417 --> 00:45:29,750 Hivyo wewe pengine kwa ujumla ukoo na firewall, 971 00:45:29,750 --> 00:45:30,990 si sana katika hali ya kimwili. 972 00:45:30,990 --> 00:45:32,470 Hivyo nyuma katika siku, na bado hadi leo hii, 973 00:45:32,470 --> 00:45:35,430 kama nimepata kama ukanda makubwa kwa mfano kwamba wana mengi ya maduka, 974 00:45:35,430 --> 00:45:38,500 ujumla kuta katika kati ya Maduka ya mtu binafsi au maduka 975 00:45:38,500 --> 00:45:43,180 ni mpenyo kwa maana kwamba wana insulation maalum 976 00:45:43,180 --> 00:45:45,310 ili kwamba kama moto mapumziko nje katika duka moja, 977 00:45:45,310 --> 00:45:48,210 hana lazima kuenea kwa duka karibu. 978 00:45:48,210 --> 00:45:51,710 >> Ulimwengu wa kompyuta pia ina firewalls kuwa kufanya kitu tofauti. 979 00:45:51,710 --> 00:45:52,798 Je fireball nini? 980 00:45:52,798 --> 00:45:53,298 Yeah? 981 00:45:53,298 --> 00:45:55,290 >> Watazamaji: Kimsingi wao kukatwa uhusiano 982 00:45:55,290 --> 00:45:59,493 kama wakutane kitu kama, kwa mfano, 983 00:45:59,493 --> 00:46:01,361 wana idadi ya kauli id. 984 00:46:01,361 --> 00:46:04,340 Na kama kitu kinachotokea, wao kukata uhusiano. 985 00:46:04,340 --> 00:46:07,570 Kama ikiwa shambulio hilo kwa makusudi [Inaudible] kompyuta yako, or-- 986 00:46:07,570 --> 00:46:08,630 >> DAVID J. Malan: Sawa nzuri. 987 00:46:08,630 --> 00:46:11,220 Naam, na kwa kweli uko hata kwenda mbele kidogo 988 00:46:11,220 --> 00:46:14,590 katika kuelezea kitu ambacho inaweza kuwa aitwaye kuingilia kugundua mfumo, 989 00:46:14,590 --> 00:46:18,305 au IDS kwa muda mfupi, ambapo wewe kweli kuwa sheria inavyoelezwa. 990 00:46:18,305 --> 00:46:22,140 Na kama huna kuanza kuona tuhuma tabia, wewe kujaribu kukomesha yake. 991 00:46:22,140 --> 00:46:24,250 >> Na firewall, kusema ukweli, katika ngazi ya mitandao, 992 00:46:24,250 --> 00:46:26,821 ni hata dumber na rahisi zaidi ya kwamba, kwa ujumla. 993 00:46:26,821 --> 00:46:29,070 Na kuna aina mbalimbali ya mpenyo duniani. 994 00:46:29,070 --> 00:46:31,569 Lakini wale ambao kazi katika kiwango cha tunazungumzia today-- 995 00:46:31,569 --> 00:46:35,330 IP na TCP-- kazi hata straightforwardly zaidi. 996 00:46:35,330 --> 00:46:39,180 >> Kwa mfano, kama ungekuwa Yale mfumo watawala, au mfumo wa Harvard 997 00:46:39,180 --> 00:46:42,020 watawala, au baadhi Big Ndugu katika baadhi ya kampuni, 998 00:46:42,020 --> 00:46:45,040 na alitaka kuzuia wote wa yako wanafunzi au yote ya wafanyakazi wako 999 00:46:45,040 --> 00:46:47,619 wasiende facebook.com, wote una kufanya 1000 00:46:47,619 --> 00:46:50,160 ni kuhakikisha kwamba wote wa zao mtandao wa trafiki, kwanza ya yote, 1001 00:46:50,160 --> 00:46:51,850 huenda kwa njia ya kifaa maalum. 1002 00:46:51,850 --> 00:46:53,030 Hebu simu yake firewall. 1003 00:46:53,030 --> 00:46:54,910 >> Na hiyo ni nzuri, kwa sababu unaweza kufanya router yako 1004 00:46:54,910 --> 00:46:57,618 kitu kimoja kama firewall kama kuweka aina hiyo ya programu 1005 00:46:57,618 --> 00:46:58,940 kwenye mashine hiyo. 1006 00:46:58,940 --> 00:47:01,780 Hivyo kama wote wanafunzi yako au wafanyakazi trafiki 1007 00:47:01,780 --> 00:47:04,450 ni kwenda kwa hii firewall kati, jinsi 1008 00:47:04,450 --> 00:47:08,540 ingekuwa sisi kuzuia watu wasiende kwa facebook.com, kwa mfano? 1009 00:47:08,540 --> 00:47:10,780 Ingekuwa mfumo gani msimamizi kufanya? 1010 00:47:10,780 --> 00:47:11,370 Mtu mwingine? 1011 00:47:11,370 --> 00:47:12,911 Hebu jaribu kwenda kote. 1012 00:47:12,911 --> 00:47:15,074 >> Watazamaji: [inaudible] 1013 00:47:15,074 --> 00:47:16,365 DAVID J. Malan: Sema kwamba tena? 1014 00:47:16,365 --> 00:47:19,215 Watazamaji: Ni lazima tu kupata hawakupata juu ndani ya mfumo. 1015 00:47:19,215 --> 00:47:22,487 Hivyo tu ya kuweka Picha katika 127.0.0-- 1016 00:47:22,487 --> 00:47:23,820 DAVID J. Malan: Ah, ya kuvutia. 1017 00:47:23,820 --> 00:47:27,290 Hivyo unaweza kweli basi hack DNS mfumo wako. 1018 00:47:27,290 --> 00:47:31,180 Hii ni kweli njia unaweza kufanya hivyo ambapo wakati wowote Yale mwanafunzi pulls 1019 00:47:31,180 --> 00:47:34,670 up www.facebook.com, kila mmoja wetu hapa leo juu ya chuo 1020 00:47:34,670 --> 00:47:38,590 wanatumia DNS server Yale wa, kwa sababu Yale ya DHCP server alitupa 1021 00:47:38,590 --> 00:47:39,580 kwamba mahali. 1022 00:47:39,580 --> 00:47:42,490 Hivyo yeah, wewe naweza aina ya kuvunja vitu au mapumziko mkataba 1023 00:47:42,490 --> 00:47:49,190 na kusema tu, ndio, facebook.com ya anwani ni feki, 1024 00:47:49,190 --> 00:47:52,530 ni 1.2.3.4, ambayo ni si kweli halali. 1025 00:47:52,530 --> 00:47:53,930 Au labda ni 278. 1026 00:47:53,930 --> 00:47:57,460 chochote kilichokuwa katika TV show a wakati iliyopita ili hakuna hata mmoja wetu 1027 00:47:57,460 --> 00:47:59,176 kweli anaweza kutembelea facebook.com. 1028 00:47:59,176 --> 00:48:00,590 >> Hivyo tuseme Yale alifanya hivyo. 1029 00:48:00,590 --> 00:48:03,336 Tuseme Yale alitaka kuweka wewe nje ya facebook.com. 1030 00:48:03,336 --> 00:48:05,700 Na kwa hiyo, wao iliyopita vipimo vya DNS 1031 00:48:05,700 --> 00:48:08,812 kukupa bogus IP kushughulikia kwa facebook.com. 1032 00:48:08,812 --> 00:48:10,616 Jinsi gani unaweza kuitikia? 1033 00:48:10,616 --> 00:48:12,990 Kitaalam, not-- loo, sasa kila mtu anataka kushiriki. 1034 00:48:12,990 --> 00:48:13,490 OK, yeah. 1035 00:48:13,490 --> 00:48:16,190 Watazamaji: Wewe tu aina katika anwani halisi ya IP ya Facebook. 1036 00:48:16,190 --> 00:48:16,710 >> DAVID J. Malan: Sawa, nzuri. 1037 00:48:16,710 --> 00:48:19,350 Hivyo tunaweza tu aina katika anwani halisi ya IP ya Facebook, 1038 00:48:19,350 --> 00:48:21,090 kiasi kama mimi na tovuti Yale ya. 1039 00:48:21,090 --> 00:48:24,636 Na kama server Picha kimeundwa kuunga mkono kwamba, ni lazima kweli kazi. 1040 00:48:24,636 --> 00:48:26,510 Ni maumivu madogo katika shingo, kwa sababu sasa sisi 1041 00:48:26,510 --> 00:48:30,220 una kukumbuka baadhi random Thamani ya 32-bit, lakini hiyo inaweza kufanya kazi. 1042 00:48:30,220 --> 00:48:31,622 Nini kingine unaweza kufanya nini? 1043 00:48:31,622 --> 00:48:32,121 Naam. 1044 00:48:32,121 --> 00:48:35,117 >> Watazamaji: Unaweza kubadilisha mazingira hayo [inaudible]. 1045 00:48:35,117 --> 00:48:37,700 DAVID J. Malan: Yeah, wewe naweza hata kubadilisha mipangilio yako DNS. 1046 00:48:37,700 --> 00:48:40,480 Hivyo kwa kweli hii ni kweli pretty muhimu, kusema ukweli, 1047 00:48:40,480 --> 00:48:45,590 kama wewe ni katika uwanja wa ndege, au kama uko katika cafe, au kitu ambacho 1048 00:48:45,590 --> 00:48:48,834 ina hafifu biashara ambapo wakati mwingine DNS server tu ataacha kazi. 1049 00:48:48,834 --> 00:48:51,000 Hivyo hata mimi mara kwa mara kufanya hivyo, si kwa makusudi, mimi 1050 00:48:51,000 --> 00:48:52,750 wanataka kutumia Facebook madhumuni, lakini kwa kweli 1051 00:48:52,750 --> 00:48:56,344 kwa sababu mimi wanaonekana kuwa na mtandao uhusiano, lakini hakuna ni kazi. 1052 00:48:56,344 --> 00:48:58,260 Na hivyo moja ya kwanza mambo mimi try-- na wewe 1053 00:48:58,260 --> 00:49:01,710 Unaweza kufanya hivyo juu ya Windows too-- lakini juu ya Mac yangu, kama mimi kwenda Network. 1054 00:49:01,710 --> 00:49:03,330 Na mimi kuchagua wangu uhusiano Wi-Fi. 1055 00:49:03,330 --> 00:49:04,750 Na mimi kwenda juu. 1056 00:49:04,750 --> 00:49:06,080 Na mimi kwenda DNS. 1057 00:49:06,080 --> 00:49:08,260 Hizi ni tatu IP kwamba Yale 1058 00:49:08,260 --> 00:49:10,290 ni kunipa kwa ajili ya tatu servrar DNS. 1059 00:49:10,290 --> 00:49:14,110 Madhumuni kisha ni kwa ajili yangu na kujaribu yoyote mmoja wa haya kutatua anwani. 1060 00:49:14,110 --> 00:49:15,946 >> Lakini siwezi kupuuza hizi kwa kufanya pamoja. 1061 00:49:15,946 --> 00:49:18,333 Na mtu yeyote wanataka kupendekeza DNS server? 1062 00:49:18,333 --> 00:49:19,120 >> Watazamaji: 8.8.8.8? 1063 00:49:19,120 --> 00:49:20,578 >> DAVID J. Malan: Oh, wewe ni ajabu. 1064 00:49:20,578 --> 00:49:21,650 Ndiyo, 8.8.8.8. 1065 00:49:21,650 --> 00:49:26,170 Hivyo Google, kubariki mioyo yao, kununua IP 8.8.8.8, 1066 00:49:26,170 --> 00:49:29,560 kwa sababu ni aina ya inaonekana kama Gs pengine, na ni rahisi kukumbuka. 1067 00:49:29,560 --> 00:49:34,820 Lakini kwa kweli, sasa mimi uliyoisanidi yangu kompyuta kwa kutumia DNS server Google. 1068 00:49:34,820 --> 00:49:38,050 >> Hivyo sasa kama mimi kwenda yale.edu, ni bado kwenda kufanya kazi. 1069 00:49:38,050 --> 00:49:40,100 Lakini mimi si kutumia Yale ya DNS server tena. 1070 00:49:40,100 --> 00:49:44,430 Na nikienda na facebook.com, wote wa wale kuangalia heka 1071 00:49:44,430 --> 00:49:45,960 ni kwenda kwa njia ya Google. 1072 00:49:45,960 --> 00:49:49,120 >> Hivyo kwa upande mmoja, nimekuwa kwa uwazi circumvented mfumo wa ndani 1073 00:49:49,120 --> 00:49:51,810 watendaji tu kwa kuelewa jinsi mitandao matendo. 1074 00:49:51,810 --> 00:49:53,360 Lakini mimi nina kulipa bei. 1075 00:49:53,360 --> 00:49:54,740 Hakuna kitu ya bure. 1076 00:49:54,740 --> 00:49:56,096 Nina nini tu wamekata? 1077 00:49:56,096 --> 00:50:00,180 1078 00:50:00,180 --> 00:50:02,250 Nina nini tu wamekata? 1079 00:50:02,250 --> 00:50:06,090 Nyote watu wajanja ambao wana wamekuwa wakitumia 8.8.8.8, kwa sababu ni baridi 1080 00:50:06,090 --> 00:50:10,440 au kutatua matatizo, nini na wamekuwa wakifanya muda wote huu? 1081 00:50:10,440 --> 00:50:11,910 >> Watazamaji: Traveling mbali? 1082 00:50:11,910 --> 00:50:15,201 >> DAVID J. Malan: Labda kusafiri mbali zaidi, kwa sababu Google pengine sio kabisa kama 1083 00:50:15,201 --> 00:50:16,770 karibu kama kompyuta chini ya mitaani. 1084 00:50:16,770 --> 00:50:18,420 Lakini zaidi worrisomely. 1085 00:50:18,420 --> 00:50:18,920 Yeah? 1086 00:50:18,920 --> 00:50:20,940 >> Watazamaji: Hivyo sasa Google anajua wapi utaenda. 1087 00:50:20,940 --> 00:50:23,856 >> DAVID J. Malan: Google anajua halisi kila tovuti wewe ni kutembelea, 1088 00:50:23,856 --> 00:50:26,080 kwa sababu wewe ni literally kuwauliza, hey Google, 1089 00:50:26,080 --> 00:50:28,360 Unaweza kutafsiri yale.edu kwa ajili yangu? 1090 00:50:28,360 --> 00:50:32,430 Au hey Google, unaweza kutafsiri hii nyingine anwani ya tovuti kwa ajili yangu 1091 00:50:32,430 --> 00:50:33,334 ndani ya IP. 1092 00:50:33,334 --> 00:50:35,750 Na hivyo they're-- Sina sijui nini wewe kuzungumza juu. 1093 00:50:35,750 --> 00:50:38,080 Na ili waweze kujua kila kitu kuhusu wewe. 1094 00:50:38,080 --> 00:50:42,180 Hivyo kutambua kwamba hii ni huduma ya bure kwa lengo kutokana na mtazamo wao 1095 00:50:42,180 --> 00:50:42,680 vilevile. 1096 00:50:42,680 --> 00:50:44,420 Lakini inaweza hakika kupata nje ya kumfunga. 1097 00:50:44,420 --> 00:50:46,380 >> Sasa tu kushughulikia mtu mwingine suala ambalo mara nyingi anakuja juu 1098 00:50:46,380 --> 00:50:48,640 miongoni mwa wanafunzi, hasa wakati wa kusafiri kimataifa 1099 00:50:48,640 --> 00:50:50,765 katika baadhi ya nchi kama China, pale ambapo kwa hakika 1100 00:50:50,765 --> 00:50:54,559 ni Firewall Mkuu wa China ambapo Serikali huko vitalu kabisa 1101 00:50:54,559 --> 00:50:56,100 kidogo ya trafiki katika ngazi mbalimbali. 1102 00:50:56,100 --> 00:50:58,141 Huwezi kuwa tu kuzuia trafiki katika ngazi 1103 00:50:58,141 --> 00:51:01,240 tunazungumzia hapa, DNS au vinginevyo, unaweza kuzuia katika ngazi nyingine. 1104 00:51:01,240 --> 00:51:04,030 >> Na kwa kweli, tu Kuwa wazi, firewall 1105 00:51:04,030 --> 00:51:08,400 wanaweza kufanya kazi hata tu zaidi ya kuwa mfumo wa watawala mabadiliko 1106 00:51:08,400 --> 00:51:09,500 DNS mazingira. 1107 00:51:09,500 --> 00:51:12,920 Firewall, kifaa katika kati ya sisi na maeneo mengine ya dunia, 1108 00:51:12,920 --> 00:51:16,850 inaweza tu kuzuia anayemaliza muda wake yoyote maombi ya IP 1109 00:51:16,850 --> 00:51:21,240 kwa Facebook juu ya bandari 80, au IP kwa harvard.edu, 1110 00:51:21,240 --> 00:51:22,580 au anwani ya IP ya kitu chochote. 1111 00:51:22,580 --> 00:51:26,280 Hivyo firewall unaweza kuangalia yako bahasha 'IP na hata bandari 1112 00:51:26,280 --> 00:51:29,384 idadi, na kama Yale alitaka, inaweza kuacha tu sisi sote 1113 00:51:29,384 --> 00:51:32,550 kutoka hata kwa kutumia FTP tena, ambayo ingekuwa pengine ni jambo zuri kwa sababu 1114 00:51:32,550 --> 00:51:34,320 ni kweli itifaki salama. 1115 00:51:34,320 --> 00:51:37,620 Yale ingeweza hata kutuzuia kutembelea ukamilifu wa mtandao 1116 00:51:37,620 --> 00:51:42,632 tu kwa ku zote bandari trafiki juu ya idadi 80 pia. 1117 00:51:42,632 --> 00:51:43,840 Hivyo hiyo inaweza kuwa ni njia nyingine. 1118 00:51:43,840 --> 00:51:45,740 Na kuna njia hata fancier pia. 1119 00:51:45,740 --> 00:51:47,770 >> Lakini wakati wewe ni kusafiri nje ya nchi kwa mfano, 1120 00:51:47,770 --> 00:51:50,740 au kama wewe ni katika mgahawa biashara, au kama wewe ni mahali popote ambapo kuna 1121 00:51:50,740 --> 00:51:53,179 blockages au vitisho, unaweza kufanya nini? 1122 00:51:53,179 --> 00:51:56,220 Naam, kama wewe kwenda chini ya mitaani kwa Starbucks au kusafiri katika uwanja wa ndege, 1123 00:51:56,220 --> 00:51:58,780 ujumla unaweza tu hop juu ya Wi-Fi kwa kuchagua 1124 00:51:58,780 --> 00:52:04,631 kama, JFK Wi-Fi la LaGuardia Wi-Fi, au Logan Airport nini si Wi-Fi, au. 1125 00:52:04,631 --> 00:52:05,880 Na si encrypted, sawa? 1126 00:52:05,880 --> 00:52:06,949 Hakuna icon kufuli. 1127 00:52:06,949 --> 00:52:09,490 Na pengine wewe si ilisababisha kwa jina la mtumiaji na neno la siri. 1128 00:52:09,490 --> 00:52:11,240 Wewe ni tu ilisababisha pamoja na baadhi ya aina kijinga 1129 00:52:11,240 --> 00:52:15,260 kusema kama, nakubaliana kutumia hii tu kwa dakika 30, au kitu kama hicho. 1130 00:52:15,260 --> 00:52:18,761 >> Lakini hakuna kuficha kati ya wewe na upatikanaji Starbucks Wi-Fi 1131 00:52:18,761 --> 00:52:20,760 uhakika, mambo kwa Antena juu ya ukuta. 1132 00:52:20,760 --> 00:52:24,840 Hakuna encryption kati ya wewe na uwanja wa ndege wa Wi-Fi ishara. 1133 00:52:24,840 --> 00:52:29,060 >> Na hivyo kitaalam, mtu huyo creepy ameketi viti chache chini kutoka kwenu 1134 00:52:29,060 --> 00:52:31,970 katika Starbucks au katika uwanja wa ndege inaweza kuwa, na programu sahihi, 1135 00:52:31,970 --> 00:52:35,164 kuangalia yote ya wireless yako trafiki juu ya mbali yake. 1136 00:52:35,164 --> 00:52:37,080 Siyo kwamba ni vigumu kuweka mbali katika nini 1137 00:52:37,080 --> 00:52:39,880 aitwaye hali ya wapenzi wengi, ambayo kama jina la kupendekeza, 1138 00:52:39,880 --> 00:52:41,760 ina maana wewe ni aina ya huru na sheria. 1139 00:52:41,760 --> 00:52:44,740 Na ni haki anasikiliza si tu kwa trafiki maana kwa ajili yake, 1140 00:52:44,740 --> 00:52:47,700 lakini pia kwa kila mtu mwingine ni trafiki ndani mbalimbali. 1141 00:52:47,700 --> 00:52:50,550 >> Na kwa mantiki hiyo, ni unaweza kuona wote wa pakiti wa habari 1142 00:52:50,550 --> 00:52:51,360 wewe ni kupokea. 1143 00:52:51,360 --> 00:52:53,510 Na kama pakiti wale si encrypted, wewe 1144 00:52:53,510 --> 00:52:56,680 ni kuweka mwenyewe katika hatari ya barua pepe yako, au ujumbe wako, 1145 00:52:56,680 --> 00:52:58,620 au kitu kingine chochote kupata wazi. 1146 00:52:58,620 --> 00:53:01,220 >> Hivyo hata kama wewe si nje ya nchi lakini wewe tu katika Starbucks, 1147 00:53:01,220 --> 00:53:03,800 au uko juu baadhi random mtu Wi-Fi kwamba si encrypted, 1148 00:53:03,800 --> 00:53:05,410 VPN ni jambo zuri. 1149 00:53:05,410 --> 00:53:07,410 VPN ni virtual mtandao binafsi. 1150 00:53:07,410 --> 00:53:09,480 Na ni teknolojia kwamba utapata kuwa na 1151 00:53:09,480 --> 00:53:14,560 encrypted, connection-- scrambled fancier kuliko Kaisari, au la Vigenere-- 1152 00:53:14,560 --> 00:53:17,420 kati ya Laptop yako, au simu yako, au desktop yako, 1153 00:53:17,420 --> 00:53:22,460 na server mahali pengine, kama server juu ya chuo Kikuu cha Yale ya. 1154 00:53:22,460 --> 00:53:25,840 >> Na kama wewe ni kusafiri abroad-- na kwa kweli, unakuta hii katika hoteli 1155 00:53:25,840 --> 00:53:26,560 muda wote. 1156 00:53:26,560 --> 00:53:28,580 Na hasa kama anayetaka wanasayansi wa kompyuta 1157 00:53:28,580 --> 00:53:32,090 ambapo nyie ili, kama geeks, wanataka kutumia bandari nyingine ya 80, 1158 00:53:32,090 --> 00:53:35,770 na bandari nyingine ya 443-- na kwa kweli kwa kuweka tatizo sita, 1159 00:53:35,770 --> 00:53:39,280 sisi ni kwenda kucheza na nyingi TCP bandari tu kwa choice-- mengi 1160 00:53:39,280 --> 00:53:42,940 wa hoteli, na maduka, na mitandao kuzuia tu kwamba aina ya mambo 1161 00:53:42,940 --> 00:53:45,970 kwa sababu wao kiasi fulani naively, au kwa ujinga, fikiria tu 1162 00:53:45,970 --> 00:53:48,010 kwamba hakuna mtu anahitaji bandari hizo nyingine. 1163 00:53:48,010 --> 00:53:51,150 >> Na hivyo kwa kutumia VPN Unaweza wewe kukwepa aina wale wa vikwazo, 1164 00:53:51,150 --> 00:53:54,050 kwa sababu gani VPN gani ni utapata katika Starbucks, 1165 00:53:54,050 --> 00:53:58,630 au uwanja wa ndege, au mahali popote duniani kuungana encryptedly kwa yale.edu, 1166 00:53:58,630 --> 00:54:02,950 kwa baadhi server hapa juu ya chuo, na kisha handaki, hivyo kusema, 1167 00:54:02,950 --> 00:54:06,570 wote wa trafiki yako kutoka popote wewe ni kupitia Yale, ambapo kiwango 1168 00:54:06,570 --> 00:54:08,720 basi huenda na marudio yake ya mwisho. 1169 00:54:08,720 --> 00:54:11,150 >> Lakini kwa encrypting yake, kuepuka yoyote ya aina hii 1170 00:54:11,150 --> 00:54:15,380 ya filters au kuwekewa kwamba baadhi ya mtandao wa ndani imeweka. 1171 00:54:15,380 --> 00:54:17,980 Na pamoja, una ulinzi zaidi imara 1172 00:54:17,980 --> 00:54:19,730 dhidi ya watu creepy karibu na wewe ambao huenda 1173 00:54:19,730 --> 00:54:21,300 kuwa akijaribu kusikiliza katika juu ya trafiki yako. 1174 00:54:21,300 --> 00:54:24,591 Bado kuna inaweza kuwa watu creepy hapa kurudi nyumbani katika Yale kuangalia trafiki yako 1175 00:54:24,591 --> 00:54:28,440 kama anakuja nje ya VPN, lakini angalau umefanya kusukuma tishio mbali mbali. 1176 00:54:28,440 --> 00:54:30,490 Na ni hapa pia, biashara mbali. 1177 00:54:30,490 --> 00:54:33,645 >> Sasa bila shaka, kama wewe ni katika China au hata katika mgahawa, 1178 00:54:33,645 --> 00:54:35,770 na wewe ni tunnel zote trafiki yako kwa njia Yale, 1179 00:54:35,770 --> 00:54:37,590 nini bei ni sisi kulipa labda? 1180 00:54:37,590 --> 00:54:38,272 >> Watazamaji: Kasi. 1181 00:54:38,272 --> 00:54:39,480 DAVID J. Malan: Kasi, sawa? 1182 00:54:39,480 --> 00:54:41,430 Kuna got kuwa baadhi math au baadhi fanciness kushiriki 1183 00:54:41,430 --> 00:54:42,574 katika encryption halisi. 1184 00:54:42,574 --> 00:54:44,990 Kuna inaweza kuwa maelfu ya maili ya umbali au maelfu 1185 00:54:44,990 --> 00:54:47,250 ya maili ya nyaya kati ya wewe na Yale. 1186 00:54:47,250 --> 00:54:49,800 Na ni mbaya kweli kama wewe ni nchini China, kwa mfano, 1187 00:54:49,800 --> 00:54:51,650 na unataka kutembelea tovuti nchini China. 1188 00:54:51,650 --> 00:54:54,230 Na hivyo data zako ni kwenda Marekani, na kisha kurejea China 1189 00:54:54,230 --> 00:54:56,620 tu kwa sababu wewe ni encrypting ni njia ya handaki hii. 1190 00:54:56,620 --> 00:54:59,960 >> Lakini kutatua kiufundi na kazi matatizo sawa. 1191 00:54:59,960 --> 00:55:02,050 Lakini yote majipu chini hizi rahisi sana mawazo. 1192 00:55:02,050 --> 00:55:06,530 Na Harvard, kwa wale curious, ina moja hapa pia, katika vpn.harvard.edu, 1193 00:55:06,530 --> 00:55:09,150 ambayo inafanya kazi hii tu kama Yale ya. 1194 00:55:09,150 --> 00:55:12,580 >> Hivyo, pamoja na yote ambayo alisema, kwa nini ni mtandao huu zima muhimu? 1195 00:55:12,580 --> 00:55:14,080 Na tunaweza kuanza kufanya na hayo? 1196 00:55:14,080 --> 00:55:15,630 Naam, hebu kufanya hili sasa zaidi ya kweli. 1197 00:55:15,630 --> 00:55:17,610 Hii ni kifupi na ambayo wengi wetu 1198 00:55:17,610 --> 00:55:22,140 pengine super familiar-- HTTP-- ambayo inasimamia kwa mfumuko Nakala uhamisho 1199 00:55:22,140 --> 00:55:22,950 itifaki. 1200 00:55:22,950 --> 00:55:26,460 Na hii ina maana tu hii ni lugha, itifaki 1201 00:55:26,460 --> 00:55:29,140 kwamba browsers mtandao na mtandao wa kompyuta kusema. 1202 00:55:29,140 --> 00:55:31,437 >> P katika HTTP ni kweli itifaki. 1203 00:55:31,437 --> 00:55:33,270 Na itifaki ni seti ya mikataba. 1204 00:55:33,270 --> 00:55:36,690 Tumeona IP-- biashara protocol-- TCP-- kudhibiti maambukizi 1205 00:55:36,690 --> 00:55:38,290 protocol-- na HTTP. 1206 00:55:38,290 --> 00:55:40,570 Lakini ni nini hii kijinga Jambo la itifaki? 1207 00:55:40,570 --> 00:55:41,930 Ni tu seti ya mikataba. 1208 00:55:41,930 --> 00:55:43,760 >> Hivyo kama mimi aina ya shuka hapa, na mimi nataka wanawasalimuni. 1209 00:55:43,760 --> 00:55:44,930 Napenda kusema hi, jina langu ni David. 1210 00:55:44,930 --> 00:55:45,600 >> Watazamaji: Luis. 1211 00:55:45,600 --> 00:55:46,475 >> DAVID J. Malan: Luis. 1212 00:55:46,475 --> 00:55:49,360 Tuna binadamu hayo ya kijinga mkataba wa kupeana mikono hapa. 1213 00:55:49,360 --> 00:55:50,570 Lakini hiyo ni itifaki, sawa? 1214 00:55:50,570 --> 00:55:51,470 Mimi kupanuliwa mkono wangu. 1215 00:55:51,470 --> 00:55:52,530 Luis kupanuliwa mkono wake. 1216 00:55:52,530 --> 00:55:53,070 Sisi alifanya hivyo. 1217 00:55:53,070 --> 00:55:54,790 Na kisha kamili, kosa. 1218 00:55:54,790 --> 00:55:58,100 >> Na hiyo ndiyo sawa roho ya itifaki ya kompyuta 1219 00:55:58,100 --> 00:56:02,770 ambapo kama katika HTTP, kile kinachotokea ni hii. 1220 00:56:02,770 --> 00:56:05,520 Kama wewe ni kompyuta juu ya kushoto hapa, na kuna baadhi ya tovuti 1221 00:56:05,520 --> 00:56:07,230 server huko juu ya haki. 1222 00:56:07,230 --> 00:56:11,130 Na kompyuta upande wa kushoto anataka kuomba habari kutoka kuwa server. 1223 00:56:11,130 --> 00:56:13,140 Ni aina ya operesheni pande mbili utawezesha. 1224 00:56:13,140 --> 00:56:15,800 Kisakuzi upande wa kushoto anauliza kwa baadhi ukurasa wa mtandao. 1225 00:56:15,800 --> 00:56:18,404 Server juu ya haki anajibu kwa baadhi ukurasa wa mtandao. 1226 00:56:18,404 --> 00:56:20,570 Na tutaweza kuona nini aina wale kuchukua katika muda tu. 1227 00:56:20,570 --> 00:56:24,311 >> Na zinageuka kuwa wale computers-- kwamba browser na server, au mteja 1228 00:56:24,311 --> 00:56:25,310 na server, hivyo kusema. 1229 00:56:25,310 --> 00:56:28,120 Kiasi kama mgahawa ambapo mteja ni kuuliza kwa kitu, 1230 00:56:28,120 --> 00:56:31,670 na server ni kuleta kwake something-- kupata 1231 00:56:31,670 --> 00:56:33,170 ni aina ya neno operative. 1232 00:56:33,170 --> 00:56:38,560 Literally ndani ya bahasha kwamba browser yangu inapeleka kutoka hapa mtandao 1233 00:56:38,560 --> 00:56:40,880 server ni neno get. 1234 00:56:40,880 --> 00:56:42,700 Kama nataka kupata habari leo. 1235 00:56:42,700 --> 00:56:45,370 Nataka kupata yangu Picha kulisha habari, au mimi 1236 00:56:45,370 --> 00:56:47,330 wanataka kupata ukurasa baadhi kutoka server. 1237 00:56:47,330 --> 00:56:50,760 >> Hasa, hii ni nini kinachoendelea ndani ya kwamba bahasha. 1238 00:56:50,760 --> 00:56:53,810 Hivyo mimi, kwa Cole, kimsingi alimtuma Cole majibu. 1239 00:56:53,810 --> 00:56:56,750 Kama unafikiri kwamba Cole kweli alitaka picha ya Rick Astley, 1240 00:56:56,750 --> 00:57:00,700 apate ulinituma ombi sawa katika roho kwa hili. 1241 00:57:00,700 --> 00:57:04,670 Ndani ya bahasha yake kwangu, ambapo Mimi sasa kucheza nafasi ya Google, 1242 00:57:04,670 --> 00:57:08,270 itakuwa ombi kwamba literally anasema, kupata, na kisha slash-- mbele 1243 00:57:08,270 --> 00:57:10,636 na ve pengine kuona mbele mikwaju katika URLs kabla. 1244 00:57:10,636 --> 00:57:13,260 Ina maana tu nipe chaguo-msingi ukurasa, chaguo-msingi Rick Astley 1245 00:57:13,260 --> 00:57:14,560 picha katika kesi hii. 1246 00:57:14,560 --> 00:57:20,100 >> Na kwa njia, Cole anaongea lugha HTTP toleo 1.1, au itifaki 1.1. 1247 00:57:20,100 --> 00:57:22,090 Na zinageuka kuna ya toleo la wazee 1.0. 1248 00:57:22,090 --> 00:57:23,910 Lakini kompyuta huwa na kutumia 1.1. 1249 00:57:23,910 --> 00:57:27,840 >> Mstari wa pili ni jambo muhimu kwamba watarejea labda kabla ya muda mrefu. 1250 00:57:27,840 --> 00:57:31,900 Lakini ni tu vipimo kwangu, mpokeaji, kwamba jambo nataka 1251 00:57:31,900 --> 00:57:33,586 ni www.google.com. 1252 00:57:33,586 --> 00:57:36,340 Kwa sababu ni rahisi sana siku hizi kwa ajili ya kadhaa, 1253 00:57:36,340 --> 00:57:39,510 mamia ya Nje na majina tofauti uwanja kwa wote 1254 00:57:39,510 --> 00:57:40,735 kuishi kwenye kompyuta moja. 1255 00:57:40,735 --> 00:57:42,860 Ni si kwenda kuwa kweli sana katika kesi ya Google. 1256 00:57:42,860 --> 00:57:45,261 Lakini katika kampuni ndogo ya kesi, inaweza kabisa kuwa. 1257 00:57:45,261 --> 00:57:47,260 Hivyo Cole ni aina tu ya kuweka katika bahasha, 1258 00:57:47,260 --> 00:57:50,840 kwa njia, wakati huu unafikia anwani yako ya IP juu ya bandari 80, 1259 00:57:50,840 --> 00:57:54,450 tu kuwa na uhakika kwamba unajua Nataka www.google.com, si 1260 00:57:54,450 --> 00:57:56,740 baadhi ya wengine tovuti random kwenye kompyuta moja. 1261 00:57:56,740 --> 00:58:00,360 >> What I kisha kujibu Cole na, mwisho wa siku, ni picha. 1262 00:58:00,360 --> 00:58:02,920 Lakini atop picha kwamba ndani ya bahasha 1263 00:58:02,920 --> 00:58:05,600 ni kweli baadhi ya maandishi, ambapo nasema, sawa. 1264 00:58:05,600 --> 00:58:07,970 Mimi nasema HTTP toleo 1.1 pia. 1265 00:58:07,970 --> 00:58:09,200 200. 1266 00:58:09,200 --> 00:58:11,730 Ambayo ni hali ya kificho kwamba wengi wetu pengine 1267 00:58:11,730 --> 00:58:14,185 kamwe kuona, kwa sababu ina maana sawa. 1268 00:58:14,185 --> 00:58:16,810 Na hii ni nzuri, kwa sababu ina maana mimi ni kukabiliana kwa mafanikio 1269 00:58:16,810 --> 00:58:18,040 ombi Cole. 1270 00:58:18,040 --> 00:58:21,930 >> Nini idadi kuwa pengine kuonekana kwenye mtandao kwamba si sawa? 1271 00:58:21,930 --> 00:58:22,780 >> Watazamaji: 404. 1272 00:58:22,780 --> 00:58:24,830 >> DAVID J. Malan: 404-- faili haikupatikana. 1273 00:58:24,830 --> 00:58:27,520 Hivyo kweli, wakati wowote wameweza kuona mmoja wa wale faili annoying si 1274 00:58:27,520 --> 00:58:31,010 makosa ya kupatikana, kwa sababu ukurasa wa mtandao amekufa, 1275 00:58:31,010 --> 00:58:34,190 au kwa sababu wewe mistyped URL, hiyo ina maana tu 1276 00:58:34,190 --> 00:58:37,600 kwamba bahasha kidogo kuwa wako kompyuta kupokea kutoka server 1277 00:58:37,600 --> 00:58:42,670 zilizomo ujumbe HTTP 1.1, 404-- haikupatikana. 1278 00:58:42,670 --> 00:58:44,930 Kwamba faili au ombi hilo Je, umefanya haupatikani. 1279 00:58:44,930 --> 00:58:48,660 >> Aidha, ndani ya bahasha kawaida ni mstari huu, aina ya maudhui. 1280 00:58:48,660 --> 00:58:51,080 Wakati mwingine ni HTML, kitu tutaweza hivi karibuni kuona. 1281 00:58:51,080 --> 00:58:52,225 Wakati mwingine ni JPEG. 1282 00:58:52,225 --> 00:58:53,100 Wakati mwingine ni GIF. 1283 00:58:53,100 --> 00:58:56,060 Wakati mwingine ni movie faili, faili la sauti, idadi yoyote ya mambo. 1284 00:58:56,060 --> 00:59:00,059 Hivyo ndani ya bahasha ni ladha kidogo kama yale Mimi kupokea. 1285 00:59:00,059 --> 00:59:03,100 Kuna namba nyingine hadhi mno, baadhi ambayo tutaweza kuchunguza katika P kuweka sita, 1286 00:59:03,100 --> 00:59:05,890 na wewe utakuwa mashaka katika P kuweka saba na / au nane. 1287 00:59:05,890 --> 00:59:08,580 Lakini baadhi hapa, kama 404 tumeona. 1288 00:59:08,580 --> 00:59:11,700 Haramu, 403, ina maana kama ruhusa ni makosa, 1289 00:59:11,700 --> 00:59:14,740 kama una si aina ya kimeundwa kwa usahihi. 1290 00:59:14,740 --> 00:59:17,830 301 na 302, sisi mara chache kuona kuibua. 1291 00:59:17,830 --> 00:59:19,150 Lakini wao maana kuelekeza. 1292 00:59:19,150 --> 00:59:21,650 Wakati wowote wewe tumeenda kwa moja URL na tumekuwa magically 1293 00:59:21,650 --> 00:59:24,410 alimtuma mahali pengine, hiyo ni kwa sababu kisakuzi ametuma nyuma 1294 00:59:24,410 --> 00:59:27,210 bahasha zenye idadi 301 au 302, 1295 00:59:27,210 --> 00:59:30,790 na URL kwamba anataka kisakuzi chako kwenda badala yake. 1296 00:59:30,790 --> 00:59:32,010 >> 500 ni ya kutisha. 1297 00:59:32,010 --> 00:59:34,842 Utaona ni kabla ya muda mrefu, pengine P kuweka sita au P kuweka saba. 1298 00:59:34,842 --> 00:59:37,050 Na kwa ujumla maana yake ni kuna baadhi ya mdudu katika kanuni yako, 1299 00:59:37,050 --> 00:59:40,000 kwa sababu kwa hakika tutaweza kuandika kificho kwamba anajibu maombi ya mtandao. 1300 00:59:40,000 --> 00:59:42,110 Na umefanya tu got baadhi kosa katika mantiki au syntax, 1301 00:59:42,110 --> 00:59:43,820 na server hawezi kushughulikia hilo. 1302 00:59:43,820 --> 00:59:47,460 >> Basi hebu angalia jinsi gani tunaweza sasa kujiinua na kuelewa maombi hayo kama ifuatavyo. 1303 00:59:47,460 --> 00:59:50,716 Kama mimi kwenda, hebu sema, google.com. 1304 00:59:50,716 --> 00:59:55,240 Hebu kwenda kwa www.google.com. 1305 00:59:55,240 --> 01:00:01,220 Na kwa ajili ya maandamano ya, hebu kuona, mimi haja ya kwenda kwa vipimo hapa. 1306 01:00:01,220 --> 01:00:03,180 Mimi nina kwenda kwa Tafuta vipimo. 1307 01:00:03,180 --> 01:00:08,236 Na Google ina inazidi annoying makala, lakini makala muhimu. 1308 01:00:08,236 --> 01:00:11,110 Hivyo Google ina jambo hili kama papo matokeo ambapo kuanza kuandika, 1309 01:00:11,110 --> 01:00:12,889 na moja kwa moja mambo kuanza kuonekana. 1310 01:00:12,889 --> 01:00:14,680 Na kwamba wote faini na utaalamu muhimu, 1311 01:00:14,680 --> 01:00:16,420 na tutaweza kuelewa kabla ya muda mrefu jinsi hii matendo. 1312 01:00:16,420 --> 01:00:18,429 Lakini kwa sasa, mimi nina kugeuka mbali matokeo ya papo, 1313 01:00:18,429 --> 01:00:20,720 kwa sababu nataka browser yangu kwa aina ya kazi na umri wa shule hivyo 1314 01:00:20,720 --> 01:00:22,940 niweze kuona nini kinaendelea. 1315 01:00:22,940 --> 01:00:23,840 >> Hivyo sasa mimi nina nyuma hapa. 1316 01:00:23,840 --> 01:00:25,090 Na mimi nataka kutafuta paka. 1317 01:00:25,090 --> 01:00:30,351 Na taarifa mimi nina kuona baadhi ya mapendekezo, baadhi ya mapendekezo hafifu sana 1318 01:00:30,351 --> 01:00:30,850 nashiriki. 1319 01:00:30,850 --> 01:00:34,730 Na sasa kama mimi hit Enter, hebu angalia nini kinatokea. 1320 01:00:34,730 --> 01:00:35,850 >> Hivyo kuna baadhi ya paka. 1321 01:00:35,850 --> 01:00:37,540 Na kibao juu ni juu ya Wikipedia. 1322 01:00:37,540 --> 01:00:39,820 Lakini leo sisi huduma ya juu teknolojia hapa. 1323 01:00:39,820 --> 01:00:42,479 Hivyo URL ambayo nimekuwa wametumwa ni hii hapa. 1324 01:00:42,479 --> 01:00:44,520 Na kuna baadhi ya mambo mimi si kweli kuelewa. 1325 01:00:44,520 --> 01:00:47,430 >> Hivyo mimi nina kwenda mbele, kwa sababu Mimi aina ya kujua jinsi Google hufanya kazi, 1326 01:00:47,430 --> 01:00:50,700 na mimi nina kwenda kwa distill hii URL katika hali yake ya rahisi. 1327 01:00:50,700 --> 01:00:52,510 Na sasa mimi nina kwenda hit Enter tena. 1328 01:00:52,510 --> 01:00:53,360 Na bado kazi. 1329 01:00:53,360 --> 01:00:55,800 Nina ukurasa wa matokeo yote kuhusu paka. 1330 01:00:55,800 --> 01:00:58,460 >> Lakini taarifa unyenyekevu wa URL yangu. 1331 01:00:58,460 --> 01:01:00,820 Ni zinageuka hii ni jinsi sehemu kubwa ya mtandao matendo. 1332 01:01:00,820 --> 01:01:03,500 Mtandao ni tu nzima rundo la kompyuta 1333 01:01:03,500 --> 01:01:05,320 kuendesha programu kwamba kuchukua pembejeo. 1334 01:01:05,320 --> 01:01:07,480 Siyo kupata kamba style pembejeo. 1335 01:01:07,480 --> 01:01:09,670 Siyo mstari amri hoja kama sisi ni kutumika. 1336 01:01:09,670 --> 01:01:13,449 Wao kuchukua pembejeo, watumishi hawa mtandao, kwa njia ya URL mara nyingi kabisa. 1337 01:01:13,449 --> 01:01:15,240 Na wakati wowote wameweza searched kwa kitu, 1338 01:01:15,240 --> 01:01:17,448 wakati wowote umefanya watumiaji katika Facebook, wakati wowote wameweza 1339 01:01:17,448 --> 01:01:20,090 jambo lolote shirikishi na ukurasa wa mtandao, nini unafanya 1340 01:01:20,090 --> 01:01:24,340 ni ufanisi kuwasilisha fomu, hivyo kwa speak-- masanduku Nakala, masanduku ya kuangalia, 1341 01:01:24,340 --> 01:01:27,880 duru kidogo, na mengineyo kwamba kutuma taarifa kutoka wewe kwa kompyuta. 1342 01:01:27,880 --> 01:01:31,960 >> Na zinageuka kuwa mtandao server anajua kuangalia kwamba URL 1343 01:01:31,960 --> 01:01:36,040 na Hazrat yake, kama kuangalia ni tabia na tabia kuangalia kwa kitu chochote 1344 01:01:36,040 --> 01:01:38,000 kuvutia baada ya swali alama. 1345 01:01:38,000 --> 01:01:40,910 Kwa sababu baada ya swali alama, ni zamu nje, atakuja 1346 01:01:40,910 --> 01:01:42,730 rundo la thamani jozi ufunguo. 1347 01:01:42,730 --> 01:01:44,570 I mean ufunguo = thamani. 1348 01:01:44,570 --> 01:01:48,130 Na kisha kama kuna multiple-- labda ampersand, baadhi nyingine muhimu = thamani, 1349 01:01:48,130 --> 01:01:50,200 ampersand, ufunguo = thamani. 1350 01:01:50,200 --> 01:01:54,560 >> Hivyo tumekuwa aina ya kuonekana wazo hili kabla ambapo kitu ina thamani. 1351 01:01:54,560 --> 01:01:55,880 Ni tu muundo mpya hapa. 1352 01:01:55,880 --> 01:01:59,040 Na mimi tu kujua, na mkataba huo, Google anatumia q kwa ajili ya swala. 1353 01:01:59,040 --> 01:02:02,670 Na kisha kama nataka kutafuta kwa ajili ya mbwa, mimi Unaweza manually kutafuta mbwa kama hicho. 1354 01:02:02,670 --> 01:02:06,360 Na kisha mimi nina inaonekana kupata matokeo baadhi la kuwashirikisha mbwa. 1355 01:02:06,360 --> 01:02:07,727 >> Hivyo kwamba inaonekana kuwa ya kuvutia. 1356 01:02:07,727 --> 01:02:10,060 Na hakika, nini kinaendelea chini ya Hood ni hii. 1357 01:02:10,060 --> 01:02:11,460 Napenda kufanya hivyo. 1358 01:02:11,460 --> 01:02:13,620 Hii ni a-- hebu angalia. 1359 01:02:13,620 --> 01:02:16,320 Hebu kwenda nyuma zaidi hapa kwa muda tu. 1360 01:02:16,320 --> 01:02:19,810 >> Tutaweza kuona kwamba kuna wengine njia za kuwasilisha taarifa. 1361 01:02:19,810 --> 01:02:25,340 Hivyo kama mimi nina magogo katika Facebook, au Gmail, au nyingine yoyote tovuti maarufu, 1362 01:02:25,340 --> 01:02:30,720 inaonekana aina ya mbaya kama chochote mimi niliandika ndani ya boksi la mwisho juu katika URL yangu, 1363 01:02:30,720 --> 01:02:32,850 katika browser yangu ya anwani bar. 1364 01:02:32,850 --> 01:02:33,690 Kwa nini? 1365 01:02:33,690 --> 01:02:35,395 Kwa nini ni kwamba upole inatia mashaka? 1366 01:02:35,395 --> 01:02:39,567 1367 01:02:39,567 --> 01:02:40,067 Yeah? 1368 01:02:40,067 --> 01:02:41,380 Watazamaji: Aina katika neno la siri. 1369 01:02:41,380 --> 01:02:41,720 DAVID J. Malan: Yeah. 1370 01:02:41,720 --> 01:02:44,000 Basi nini kama kile nimekuwa typed katika ni neno langu la siri? 1371 01:02:44,000 --> 01:02:47,881 Mimi aina ya hawataki hivyo ni wazi inayoonekana katika browser yangu ya anwani bar. 1372 01:02:47,881 --> 01:02:50,630 Moja, kwa sababu rafiki yangu annoying inaelekea kuangalia juu ya bega langu, 1373 01:02:50,630 --> 01:02:53,980 na anaweza sasa kuona, hata kama ilikuwa risasi wakati mimi nina kuandika katika, 1374 01:02:53,980 --> 01:02:54,810 kidogo duru. 1375 01:02:54,810 --> 01:02:56,010 Sasa ni katika bar anwani yangu. 1376 01:02:56,010 --> 01:02:59,270 >> Aidha, nini kweli kuhusu mambo wewe huwa na aina katika bar ya mahali. 1377 01:02:59,270 --> 01:03:00,230 >> Watazamaji: [inaudible] 1378 01:03:00,230 --> 01:03:01,505 >> DAVID J. Malan: Nini hiyo? 1379 01:03:01,505 --> 01:03:02,630 Watazamaji: Ni anapata alimtuma nje. 1380 01:03:02,630 --> 01:03:03,510 DAVID J. Malan: Ni anapata alimtuma nje. 1381 01:03:03,510 --> 01:03:05,102 Na pia, anapata kukumbukwa. 1382 01:03:05,102 --> 01:03:07,060 Kwa sababu wakati mwingine aina ya mambo huko, 1383 01:03:07,060 --> 01:03:10,440 mara nyingi ni autocompletes na anakumbuka nini umefanya typed kabla. 1384 01:03:10,440 --> 01:03:13,850 Na hivyo kuna historia hii veritable kwamba ndugu yako, au roommate yako, 1385 01:03:13,850 --> 01:03:16,830 au mtu anaweza kutembea kwa njia ya pretty much kuona kila tovuti 1386 01:03:16,830 --> 01:03:19,760 wewe alitembelea kwa sababu ni watumiaji katika bar kwamba mahali. 1387 01:03:19,760 --> 01:03:22,790 >> Aidha, tuseme unataka kupakia picha kwa Facebook. 1388 01:03:22,790 --> 01:03:26,520 Jinsi katika dunia ni wewe kwenda kuweka picha katika URL? 1389 01:03:26,520 --> 01:03:30,217 >> Naam ni zamu nje unaweza kufanya hivyo katika baadhi njia, lakini ni hakika si dhahiri. 1390 01:03:30,217 --> 01:03:33,050 Na hivyo kuna njia hii wengine wa kupeleka taarifa katika bahasha, 1391 01:03:33,050 --> 01:03:35,680 si kupitia GET, lakini kupitia kitu kinachoitwa POST. 1392 01:03:35,680 --> 01:03:38,060 Na katika nadharia, inaonekana pretty kiasi sawa. 1393 01:03:38,060 --> 01:03:41,270 Badala ya neno kupata, tunasema POST, na kisha moja aina ya format. 1394 01:03:41,270 --> 01:03:43,310 >> Kwa mfano, hii ni Je, ungependa wa nini 1395 01:03:43,310 --> 01:03:46,920 ili kuangalia kama kama mimi kujaribu magogo ndani ya Facebook, ambayo hutuma mimi faili 1396 01:03:46,920 --> 01:03:51,230 aitwaye login.php, ambayo ni kweli bado mpaka leo jina lake kama hizo. 1397 01:03:51,230 --> 01:03:53,910 Ni sawa filename Mark alitoa yake miaka mingi iliyopita. 1398 01:03:53,910 --> 01:03:58,520 Ni mpango aliandika katika PHP kupitia ambazo watumiaji wanaweza kujumuika kwa tovuti. 1399 01:03:58,520 --> 01:04:00,370 >> Lakini unahitaji kutuma baadhi ya pembejeo za ziada. 1400 01:04:00,370 --> 01:04:05,170 Na badala ya yake kwenda baada ya faili jina kama ilivyokuwa kabla na cats-- 1401 01:04:05,170 --> 01:04:09,720 q = cats-- inaweza kwenda chini katika ombi, zaidi ndani ya bahasha kama wewe 1402 01:04:09,720 --> 01:04:12,440 mapenzi ambapo hakuna mtu anayeweza kuona hivyo, na ambapo haina kuishia 1403 01:04:12,440 --> 01:04:15,670 katika browser mtumiaji bar, na kwa hiyo kukumbuka kwa watu kuchungulia 1404 01:04:15,670 --> 01:04:16,290 kote. 1405 01:04:16,290 --> 01:04:21,260 >> Na hivyo hapa anwani yangu ya barua pepe na nenosiri langu bandia kweli kwenda. 1406 01:04:21,260 --> 01:04:27,400 Na kama Facebook ni kutumia si HTTP, lakini HTTPS, 1407 01:04:27,400 --> 01:04:30,710 huu wote watakuwa encrypted, scrambled, ala Kaisari, au la Vigenere, 1408 01:04:30,710 --> 01:04:34,960 lakini zaidi fancily hivyo kwamba hakuna mtu unaweza kweli kuona ombi hili. 1409 01:04:34,960 --> 01:04:38,120 >> Na hivyo kweli kweli, wakati wowote una URL kwamba huanza na HTTPS, 1410 01:04:38,120 --> 01:04:39,560 ni njia tu ni ya siri. 1411 01:04:39,560 --> 01:04:42,710 Lakini mwisho wa siku, nini kweli ndani ya bahasha hizi? 1412 01:04:42,710 --> 01:04:44,070 Hii ilikuwa ni kiwango cha super chini. 1413 01:04:44,070 --> 01:04:46,240 Na kwa bahati nzuri, sisi siyo kwenda inge 1414 01:04:46,240 --> 01:04:49,310 kwenda ngazi hivyo chini kila wakati kwa kuanza kuandika programu ya kuvutia. 1415 01:04:49,310 --> 01:04:51,060 Tunaweza kuanza kuchukua mawazo ya wiki moja 1416 01:04:51,060 --> 01:04:54,020 kupitia tano, kudhani kwamba kuna sasa miundombinu hii kwamba 1417 01:04:54,020 --> 01:04:57,160 lets sisi kuandika programu kwamba kazi kwenye mtandao, 1418 01:04:57,160 --> 01:05:00,120 na ni kwenda kuruhusu sisi huu kuja wiki kuanza 1419 01:05:00,120 --> 01:05:01,840 kuangalia kitu kinachoitwa HTML. 1420 01:05:01,840 --> 01:05:04,750 Hii ni mambo ambayo hata zaidi ndani ya bahasha, 1421 01:05:04,750 --> 01:05:06,150 lakini ni mambo tuko kwenda kuanza kuandika. 1422 01:05:06,150 --> 01:05:08,020 Na ni mambo zaidi linalovutia, tuko 1423 01:05:08,020 --> 01:05:11,420 kwenda kuandika mipango ambayo kuanza kuzalisha moja kwa moja 1424 01:05:11,420 --> 01:05:15,410 ili tovuti yetu si ngumu coded, lakini kuchukua pembejeo na kuzalisha pato. 1425 01:05:15,410 --> 01:05:18,810 >> Pengine hii ni rahisi mtandao ukurasa unaweza kufanya katika dunia. 1426 01:05:18,810 --> 01:05:23,000 Siwezi kweli kufungua kitu kijinga kama TextEdit 1427 01:05:23,000 --> 01:05:26,160 juu ya Mac yangu, ambayo tu anitiaye dirisha rahisi Nakala kama hii. 1428 01:05:26,160 --> 01:05:29,510 Watumiaji PC na Notepad.ext, ambayo ni sawa katika roho. 1429 01:05:29,510 --> 01:05:33,212 >> Na siwezi literally aina nje Haya DOCTYPE HTML, 1430 01:05:33,212 --> 01:05:34,420 ambayo inaonekana kidogo cryptic. 1431 01:05:34,420 --> 01:05:35,850 Lakini tutaweza kuja nyuma na kwamba. 1432 01:05:35,850 --> 01:05:38,730 HTML, na haya weird mabano angled na mikwaju, 1433 01:05:38,730 --> 01:05:42,240 ndani ya ambayo sasa mimi nina kwenda kusema hiyo inakuja mkuu wa mtandao ukurasa wangu. 1434 01:05:42,240 --> 01:05:45,220 Ndani ya kwamba, mimi tu Unajua, na utasikia hivi karibuni kujua, 1435 01:05:45,220 --> 01:05:47,850 niweze kuweka jina la mtandao ukurasa wangu. 1436 01:05:47,850 --> 01:05:49,720 Na kisha chini mkuu wa ukurasa wa mtandao ni 1437 01:05:49,720 --> 01:05:51,972 kwenda kwenda kinachojulikana mwili wa ukurasa wa mtandao. 1438 01:05:51,972 --> 01:05:54,180 Na mimi nina tu indenting tu kama katika C na aina ya kuweka 1439 01:05:54,180 --> 01:05:57,620 mambo vizuri someka stylistically. 1440 01:05:57,620 --> 01:06:04,745 Na sasa mimi nina kwenda kuokoa hii kama faili kwenye eneo kazi, iitwayo hello.html yangu. 1441 01:06:04,745 --> 01:06:06,770 >> Na mimi nina kwenda kupeleka habari ndiyo, kutumia HTML. 1442 01:06:06,770 --> 01:06:09,690 Je, si mabadiliko hayo kwa Txt, hata ingawa yote haya ni faili maandishi, 1443 01:06:09,690 --> 01:06:12,130 kama C mpango Imeandikwa na mhariri wa maandishi. 1444 01:06:12,130 --> 01:06:15,080 Ingawa si katika CS50 IDE katika muda, tu hapa juu ya Mac yangu. 1445 01:06:15,080 --> 01:06:18,490 >> Na kama mimi sasa kwenda eneo kazi yangu, utaona hello.html. 1446 01:06:18,490 --> 01:06:20,720 Kama mimi bonyeza mara mbili hii, itafungua Chrome. 1447 01:06:20,720 --> 01:06:23,260 Na hata kama faili hili hutokea kuishi kwenye eneo kazi yangu, 1448 01:06:23,260 --> 01:06:26,550 kwamba labda ni rahisi ukurasa wa mtandao mimi naweza kufanya. 1449 01:06:26,550 --> 01:06:30,080 >> Taarifa kwamba jina la tab njia ya juu juu ni hujambo dunia. 1450 01:06:30,080 --> 01:06:32,470 Mwili wa ukurasa wa mtandao ni kweli hujambo dunia. 1451 01:06:32,470 --> 01:06:35,830 Na wote mimi tumefanya kupata hatua hii ni kutekeleza, 1452 01:06:35,830 --> 01:06:38,342 au ni kuandika lugha mpya, iitwayo HTML. 1453 01:06:38,342 --> 01:06:40,300 Siyo programu lugha kama C. Kuna 1454 01:06:40,300 --> 01:06:42,508 si kwenda kuwa hali, na tanzi, na kazi. 1455 01:06:42,508 --> 01:06:46,560 Ni lugha ghafi, ambapo kesi tu kuwaambia kupokea 1456 01:06:46,560 --> 01:06:48,410 Mpango nini unataka kufanya. 1457 01:06:48,410 --> 01:06:51,195 Hii ina maana hey browser, hiyo inakuja ukurasa HTML. 1458 01:06:51,195 --> 01:06:53,040 Hey browser, hiyo inakuja mkuu wa ukurasa wangu. 1459 01:06:53,040 --> 01:06:55,130 Hey browser, hiyo inakuja mwili wa ukurasa wangu. 1460 01:06:55,130 --> 01:06:57,100 Hey browser, hiyo ni kwa ajili ya mwili. 1461 01:06:57,100 --> 01:06:59,350 Hiyo ni kwa ajili ukurasa HTML. 1462 01:06:59,350 --> 01:07:03,560 >> Na kwa wale rahisi ufafanuzi peke yake, tutaweza hivi karibuni kuona kwamba moja, 1463 01:07:03,560 --> 01:07:05,122 tunaweza kuwakilisha huu kama mti. 1464 01:07:05,122 --> 01:07:06,080 Lakini zaidi juu ya baadaye. 1465 01:07:06,080 --> 01:07:08,788 Hivyo hii itakuwa zote kuunganisha kwa hivi karibuni data miundo yetu. 1466 01:07:08,788 --> 01:07:12,460 Mbili, tutaweza kuanzisha utani huu kijinga. 1467 01:07:12,460 --> 01:07:15,680 Hii ni tatoo halisi kwamba guy hii alikuwa kwenye shingo yake. 1468 01:07:15,680 --> 01:07:19,660 Pengine ni funny wiki ya kwanza au mbili, na baada ya hapo, labda sio sana. 1469 01:07:19,660 --> 01:07:22,960 >> Lakini HTML, na hata mtandao ukurasa mimi tu alifanya, super akili 1470 01:07:22,960 --> 01:07:25,670 numbingly disappointing-- kusema tu hujambo dunia 1471 01:07:25,670 --> 01:07:27,210 katika maandishi nyeusi kwenye background nyeupe. 1472 01:07:27,210 --> 01:07:28,680 Hakika tunaweza kufanya vizuri zaidi. 1473 01:07:28,680 --> 01:07:31,552 Na tutaweza kufanya hivyo kwa kuanzisha lugha mwingine aitwaye CSS. 1474 01:07:31,552 --> 01:07:34,760 Hii pia si Programu language-- hakuna tanzi, na masharti, au kwa tanzi, 1475 01:07:34,760 --> 01:07:38,470 lakini kwa kweli, tu syntax ambayo tunaweza kusema, kufanya Nakala hii kubwa. 1476 01:07:38,470 --> 01:07:39,415 Kufanya Nakala hii ndogo. 1477 01:07:39,415 --> 01:07:40,040 Haki align yake. 1478 01:07:40,040 --> 01:07:40,650 Kushoto align yake. 1479 01:07:40,650 --> 01:07:41,195 Matokeo yake ni nyekundu. 1480 01:07:41,195 --> 01:07:41,820 Matokeo yake ni rangi ya zambarau. 1481 01:07:41,820 --> 01:07:42,650 Matokeo yake ni bluu. 1482 01:07:42,650 --> 01:07:44,860 Au kufanya idadi yoyote ya Athari nyingine ya kuona. 1483 01:07:44,860 --> 01:07:48,590 Na hivyo tutaweza kuona jinsi ya kuanza stylizing kurasa za mtandao ili waweze kuangalia kwa namna 1484 01:07:48,590 --> 01:07:50,480 karibu na nini tunataka. 1485 01:07:50,480 --> 01:07:56,930 >> Na Mwisho, tuna hakika kuharibiwa labda sehemu kubwa ya TV na filamu kwa ajili yenu. 1486 01:07:56,930 --> 01:07:58,930 Nilidhani tunatarajia mwisho hapa na sekunde yetu ya mwisho 1487 01:07:58,930 --> 01:08:03,700 juu ya kipande cha mwisho ambayo inaonyesha jinsi kukatwakatwa juu ya matendo ya mtandao. 1488 01:08:03,700 --> 01:08:06,250 Kama tunaweza dim taa wakati mmoja mwisho. 1489 01:08:06,250 --> 01:08:07,250 >> [VIDEO avspelning] 1490 01:08:07,250 --> 01:08:09,520 >> -Hakuna njia. 1491 01:08:09,520 --> 01:08:10,650 Mimi nina kupata hacked. 1492 01:08:10,650 --> 01:08:11,770 >> -Okorsky? 1493 01:08:11,770 --> 01:08:14,230 >> -No-- Hakuna, hii ni kubwa. 1494 01:08:14,230 --> 01:08:17,074 Tayari wameweza kuchomwa moto kupitia NCIS umma firewall. 1495 01:08:17,074 --> 01:08:19,990 -Naam, Kujitenga nodi na dampo nao huko ng'ambo ya router. 1496 01:08:19,990 --> 01:08:20,990 -Ninajaribu. 1497 01:08:20,990 --> 01:08:23,990 Ni kusonga haraka sana. 1498 01:08:23,990 --> 01:08:25,179 >> -Oh, Hii ​​si nzuri. 1499 01:08:25,179 --> 01:08:27,470 Wao ni kutumia uhusiano wetu [Inaudible] Mbegu hii. 1500 01:08:27,470 --> 01:08:28,458 Kuzuia yake. 1501 01:08:28,458 --> 01:08:28,958 -I Hawawezi. 1502 01:08:28,958 --> 01:08:29,454 Ni shambulizi uhakika. 1503 01:08:29,454 --> 01:08:31,438 Yeye au yeye ni tu kwenda baada ya mashine yangu. 1504 01:08:31,438 --> 01:08:32,430 >> -Ni Haiwezekani. 1505 01:08:32,430 --> 01:08:33,847 Kuna DOD encryption cha mgodi. 1506 01:08:33,847 --> 01:08:35,055 Itachukua miezi kwa get-- 1507 01:08:35,055 --> 01:08:35,857 -Hey, Ni nini hiyo? 1508 01:08:35,857 --> 01:08:36,398 Mchezo video? 1509 01:08:36,398 --> 01:08:37,886 >> -Hakuna Tony, sisi ni kupata hacked. 1510 01:08:37,886 --> 01:08:40,795 >> -Kama Wao kupata katika kompyuta Abby ya, nzima NCIS mtandao ni ijayo. 1511 01:08:40,795 --> 01:08:42,050 >> -I Haiwezi kumzuia. 1512 01:08:42,050 --> 01:08:43,050 Kufanya kitu McGee. 1513 01:08:43,050 --> 01:08:44,550 >> I 've kamwe kuona kanuni kama hii. 1514 01:08:44,550 --> 01:08:47,432 1515 01:08:47,432 --> 01:08:48,571 -Oh. 1516 01:08:48,571 --> 01:08:49,196 -ambapo Ni kwenda? 1517 01:08:49,196 --> 01:08:50,604 Abby? 1518 01:08:50,604 --> 01:08:51,520 -I Hawajafanya jambo lolote. 1519 01:08:51,520 --> 01:08:53,020 Nilidhani wewe alivyofanya. 1520 01:08:53,020 --> 01:08:54,520 >> -Hakuna. 1521 01:08:54,520 --> 01:08:57,232 >> -I Alivyofanya. 1522 01:08:57,232 --> 01:08:58,307 >> [Mwisho avspelning] 1523 01:08:58,307 --> 01:09:00,390 DAVID J. Malan: bora sehemu ni watu wawili kuandika 1524 01:09:00,390 --> 01:09:02,170 kwenye keyboard wakati huo huo. 1525 01:09:02,170 --> 01:09:03,200 >> Hivyo kwamba ni kwa CS50. 1526 01:09:03,200 --> 01:09:04,700 Tutaweza fimbo karibu kwa masaa ya ofisi. 1527 01:09:04,700 --> 01:09:06,344 Na tutaweza kuona wewe wakati ujao. 1528 01:09:06,344 --> 01:09:07,760 [Music kucheza - "Seinfeld THEME"] 1529 01:09:07,760 --> 01:09:11,139 1530 01:09:11,139 --> 01:09:11,680 Hii ni CS50. 1531 01:09:11,680 --> 01:09:17,960 1532 01:09:17,960 --> 01:09:20,854 Sitaki kuwa maharamia. 1533 01:09:20,854 --> 01:09:21,770 SPIKA 2: Yarr Daudi. 1534 01:09:21,770 --> 01:09:23,700 Ni doublet faini wewe kuwa amevaa. 1535 01:09:23,700 --> 01:09:26,450 Mengi ya luff kwa kuwa puff. 1536 01:09:26,450 --> 01:09:29,327