Jadawalin cibiyar sadarwar kwamfuta ta ARPA na Yuni 1967. Da'irar mara komai ita ce kwamfuta tare da hanyar shiga, da'irar da ke da layi tasha ce ga mai amfani ɗaya.
Sauran labarai a cikin jerin:
- Tarihin relay
- Tarihin kwamfutocin lantarki
- Tarihin transistor
- Tarihin Intanet
Zuwa karshen 1966 tare da kuɗin ARPA, ya ƙaddamar da wani aiki don haɗa kwamfutoci da yawa zuwa tsarin guda ɗaya, wanda aka yi wahayi zuwa ga ra'ayin "» .
Taylor ya mika alhakin aiwatar da aikin zuwa hannaye masu iya aiki . A cikin shekarar da ta biyo baya, Roberts ya yanke shawarwari masu mahimmanci da yawa waɗanda za su sake bayyana a cikin gine-ginen fasaha da al'adun ARPANET da magadansa, a wasu lokuta shekaru masu zuwa. Shawarar farko mai mahimmanci, ko da yake ba a lissafin lokaci ba, ita ce ƙayyadaddun tsarin tafiyar da saƙonni daga wannan kwamfuta zuwa waccan.
matsala
Idan kwamfuta A tana son aika sako zuwa kwamfutar B, ta yaya wannan sakon zai sami hanyarsa daga wannan zuwa wancan? A ka'ida, zaku iya ƙyale kowane kumburi a cikin hanyar sadarwar sadarwa don sadarwa tare da kowane kumburi ta haɗa kowane kumburi zuwa kowane kumburi tare da igiyoyi na zahiri. Don sadarwa tare da B, kwamfuta A kawai za ta aika sako tare da kebul mai fita da ke haɗa shi zuwa B. Irin wannan hanyar sadarwa ana kiranta mesh network. Koyaya, ga kowane girman cibiyar sadarwa mai mahimmanci, wannan hanyar da sauri zata zama mara amfani yayin da adadin haɗin ke ƙaruwa yayin da murabba'in adadin nodes (kamar (n2 - n)/2 ya zama daidai).
Don haka, ana buƙatar wasu hanyoyin gina hanyar saƙo, wanda, da isar saƙon a kulli na tsaka-tsaki, zai ƙara tura shi zuwa ga abin da ake nufi. A farkon shekarun 1960, akwai hanyoyi guda biyu na asali don magance wannan matsala. Na farko shine hanyar adana-da-gaba na sauya saƙo. An yi amfani da wannan hanyar ta hanyar tsarin telegraph. Lokacin da saƙo ya isa kulli na tsaka-tsaki, an adana shi na ɗan lokaci a wurin (yawanci a cikin nau'in tef ɗin takarda) har sai an iya isar da shi gaba zuwa ga abin da aka yi niyya, ko kuma zuwa wata tsakiyar tsakiyar da ke kusa da abin da aka nufa.
Daga nan sai wayar ta zo kuma ana buƙatar sabuwar hanya. Jinkiri na mintuna da yawa bayan kowace magana da aka yi ta wayar, wanda dole ne a cire shi kuma a watsa shi zuwa wurin da zai nufa, zai ba da jin zance da mai shiga tsakani a duniyar Mars. Madadin haka, wayar ta yi amfani da juyawa. Mai kiran ya fara kowane kira ta hanyar aika sako na musamman da ke nuna wanda yake so ya kira. Da farko sun yi hakan ne ta hanyar yin magana da ma’aikacin, sannan suka buga lamba, wanda aka sarrafa ta da kayan aiki na atomatik a kan na’urar sauyawa. Mai aiki ko kayan aiki sun kafa keɓancewar haɗin lantarki tsakanin mai kira da wanda ake kira. A cikin yanayin kira mai nisa, wannan na iya buƙatar maimaitawa da yawa waɗanda ke haɗa kiran ta hanyar maɓalli da yawa. Da zarar an kafa haɗin, za a iya fara tattaunawar da kanta, kuma haɗin ya kasance har sai daya daga cikin bangarorin ya katse shi ta hanyar katsewa.
Sadarwar dijital, wanda aka yanke shawarar amfani da shi a cikin ARPANET don haɗa kwamfutoci masu aiki bisa ga tsarin , an yi amfani da fasali na duka telegraph da tarho. A gefe guda, an watsa saƙonnin bayanai a cikin fakiti daban-daban, kamar a kan telegraph, maimakon a ci gaba da tattaunawa ta wayar tarho. Koyaya, waɗannan saƙonnin na iya zama masu girma dabam dabam don dalilai daban-daban, daga umarnin wasan bidiyo na haruffa da yawa a tsayi, zuwa manyan fayilolin da aka canjawa wuri daga kwamfuta zuwa waccan. Idan an jinkirta fayiloli a hanyar wucewa, babu wanda ya koka game da shi. Amma mu'amala mai nisa yana buƙatar amsa mai sauri, kamar kiran waya.
Wani muhimmin bambanci tsakanin hanyoyin sadarwa na bayanai na kwamfuta a daya bangaren, da kuma wayar tarho da telegraph a daya bangaren, ita ce fahimtar kurakurai a cikin bayanan da injina ke sarrafa su. Canji ko asara yayin watsa harafi ɗaya a cikin wayar tarho, ko ɓacewar sashe na kalma a cikin tattaunawar wayar da kyar ba zai iya dagula sadarwar mutane biyu ba. Amma idan hayaniyar kan layi ta sauya sau ɗaya daga 0 zuwa 1 a cikin umarnin da aka aika zuwa kwamfuta mai nisa, zai iya canza ma'anar umarnin gaba ɗaya. Don haka, dole ne a bincika kowane saƙo don kurakurai kuma a yi fushi idan an sami wani. Irin wannan sake kunnawa zai yi tsada da yawa ga manyan saƙonni kuma suna iya haifar da kurakurai saboda sun ɗauki tsawon lokaci don aikawa.
Maganin wannan matsala ya fito ne daga abubuwa biyu masu zaman kansu da suka faru a cikin 1960, amma wanda ya zo daga baya ya fara lura da Larry Roberts da ARPA.
Ganawa
A cikin faɗuwar shekara ta 1967, Roberts ya isa Gatlinburg, Tennessee, daga ƙetaren gandun daji na Babban Dutsen Smoky, don ba da daftarin aiki da ke bayyana tsare-tsaren hanyar sadarwa na ARPA. Ya shafe kusan shekara guda yana aiki a Ofishin Fasahar Sadarwar Watsa Labarai (IPTO), amma da yawa daga cikin bayanan aikin sadarwar har yanzu ba su da tabbas, gami da magance matsalar ta hanyar sadarwa. Baya ga nassoshi marasa tushe game da tubalan da girmansu, kawai magana game da shi a cikin aikin Roberts shine taƙaitaccen bayani mai banƙyama a ƙarshensa: “Da alama ya zama dole a kula da layin sadarwa na lokaci-lokaci don samun martani a cikin kashi ɗaya bisa goma zuwa ɗaya. lokaci na biyu da ake buƙata don aiki tare. Wannan yana da tsada sosai dangane da albarkatun cibiyar sadarwa, kuma sai dai idan ba za mu iya yin kira cikin sauri ba, sauya saƙo da maida hankali za su zama mahimmanci ga mahalarta cibiyar sadarwa." Babu shakka, a lokacin, har yanzu Roberts bai yanke shawarar yin watsi da tsarin da ya yi amfani da shi da Tom Marrill a 1965 ba, wato, haɗa kwamfutoci ta hanyar sadarwar tarho da aka canza ta amfani da autodial.
Ba zato ba tsammani, wani mutum ya kasance a wurin taron tattaunawa guda tare da mafi kyawun ra'ayi don magance matsala ta hanyar sadarwa a cikin hanyoyin sadarwar bayanai. Roger Scantlebury ya tsallaka Tekun Atlantika, ya iso daga dakin gwaje-gwaje na Jiki na Biritaniya (NPL) tare da rahoto. Scantlebury ya ɗauki Roberts gefe bayan rahotonsa ya gaya masa game da ra'ayinsa. . Wannan fasaha ya samo asali ne daga maigidansa a NPL, Donald Davis. A Amurka, nasarorin Davis da tarihin ba a san su ba, kodayake a cikin faɗuwar 1967 ƙungiyar Davis a NPL ta kasance aƙalla shekara guda a gaban ARPA tare da ra'ayoyinta.
Davis, kamar yawancin majagaba na farko na lissafin lantarki, masanin kimiyya ne ta horo. Ya sauke karatu daga Imperial College London a 1943 yana da shekaru 19 kuma nan da nan aka yarda da shi cikin shirin sirrin makamin nukiliya mai suna. . A can ne ya kula da ƙungiyar masu lissafin ɗan adam waɗanda suka yi amfani da na'urori masu ƙididdigewa na inji da na lantarki don samar da hanyoyin lambobi da sauri ga matsalolin da suka shafi haɗakar makaman nukiliya (mai kula da shi shine. , Bajamushe masanin kimiyyar lissafi wanda a wancan lokacin ya riga ya fara tura asirin makaman nukiliya zuwa USSR). Bayan yakin, ya ji ta bakin masanin lissafi John Womersley game da wani aiki da yake jagoranta a NPL - shi ne ƙirƙirar na'ura mai kwakwalwa wanda ya kamata ya yi ƙididdiga iri ɗaya cikin sauri. mai suna ACE, "injin sarrafa kwamfuta ta atomatik".
Davis yayi tsalle akan ra'ayin kuma ya sanya hannu tare da NPL da sauri kamar yadda zai iya. Bayan da ya ba da gudummawa ga cikakken ƙira da gina kwamfutar ACE, ya kasance mai zurfi a cikin fannin lissafi a matsayin jagoran bincike a NPL. A cikin 1965 ya kasance a Amurka don wani taron ƙwararru mai alaƙa da aikinsa kuma ya yi amfani da damar don ziyartar manyan wuraren kwamfutoci masu yawa don ganin abin da ke tattare da hayaniya. A cikin yanayin kwamfuta na Biritaniya, raba lokaci a ma'anar musayar hulɗar kwamfuta ta masu amfani da yawa na Amurka ba a sani ba. Maimakon haka, raba lokaci yana nufin rarraba nauyin aikin kwamfuta a tsakanin shirye-shiryen sarrafa batch da yawa (ta yadda, misali, wani shirin zai yi aiki yayin da wani ya shagala da karatun tef). Sannan wannan zabin za a kira shi multiprogramming.
Yawo da Davis ya kai shi zuwa Project MAC a MIT, da JOSS Project a RAND Corporation a California, da Dartmouth Time Sharing System a New Hampshire. A kan hanyar komawa gida, ɗaya daga cikin abokan aikinsa ya ba da shawarar yin taron bita kan rabawa don ilimantar da al'ummar Biritaniya game da sabbin fasahohin da suka koya game da su a Amurka. Davis ya yarda, kuma ya karbi bakuncin da yawa daga cikin manyan mutane a fagen lissafin Amurka, ciki har da (wanda ya kirkiro "Tsarin Rarraba Lokaci Mai Ma'amala" a MIT) da Larry Roberts da kansa.
A yayin taron karawa juna sani (ko watakila nan da nan bayan haka), Davis ya buge da ra'ayin cewa ana iya amfani da falsafar raba lokaci akan layukan sadarwa na kwamfuta, ba kawai ga kwamfutocin kansu ba. Kwamfutoci masu raba lokaci suna ba kowane mai amfani da ɗan lokaci kaɗan na CPU sannan su canza zuwa wani, yana ba kowane mai amfani da tunanin samun kwamfutar da ke hulɗa da su. Hakazalika, ta hanyar yanke kowane saƙo zuwa ƙayyadaddun ma'auni, wanda Davis ya kira "packets," ana iya raba tashar sadarwa guda ɗaya tsakanin yawancin kwamfutoci ko masu amfani da kwamfuta guda ɗaya. Haka kuma, zai magance duk wani nau'in watsa bayanai wanda wayoyin tarho da telegraph ba su dace da su ba. Mai amfani da ke aiki da tashar sadarwa mai aika gajerun umarni da karɓar gajerun amsoshi ba za a toshe shi ta babban canja wurin fayil ba saboda za a raba canja wuri zuwa fakiti da yawa. Duk wani cin hanci da rashawa a cikin irin waɗannan manyan saƙonnin zai shafi fakiti ɗaya, wanda za'a iya sake aikawa cikin sauƙi don kammala saƙon.
Davis ya bayyana ra'ayoyinsa a cikin takarda na 1966 da ba a buga ba, "Shawarwari don Cibiyar Sadarwar Sadarwar Dijital." A wancan lokacin, cibiyoyin sadarwar tarho mafi ci gaba sun kasance a kan hanyar yin amfani da na'ura mai kwakwalwa ta kwamfuta, kuma Davis ya ba da shawarar shigar da fakitin sauya sheka zuwa cibiyar sadarwar tarho na gaba, samar da hanyar sadarwa ta hanyar sadarwa guda ɗaya mai iya biyan buƙatu iri-iri, daga kiran waya mai sauƙi zuwa nesa. damar yin amfani da kwamfutoci. A lokacin, an ƙara Davis zuwa manajan NPL kuma ya kafa ƙungiyar sadarwar dijital a ƙarƙashin Scantlebury don aiwatar da aikinsa da ƙirƙirar demo mai aiki.
A cikin shekarar da ta kai ga taron Gatlinburg, ƙungiyar Scantlebury ta yi aiki da duk cikakkun bayanai na ƙirƙirar hanyar sadarwa ta fakiti. Za a iya tsira da gazawar kumburi guda ɗaya ta hanyar daidaitawa wanda zai iya ɗaukar hanyoyi da yawa zuwa wurin da aka nufa, kuma ana iya magance gazawar fakiti ɗaya ta hanyar sake tura shi. Kwaikwayo da bincike sun ce mafi kyawun girman fakitin zai zama 1000 bytes - idan kun sanya shi ya fi ƙanƙanta, to, yawan amfani da bandwidth na layin don metadata a cikin taken zai yi yawa, da yawa - kuma lokacin amsawa ga masu amfani da mu'amala zai karu. sau da yawa saboda manyan saƙonni .
Ayyukan Scantlebury sun haɗa da cikakkun bayanai kamar tsarin fakitin...
...da kuma nazarin tasirin girman fakiti akan latency na cibiyar sadarwa.
A halin yanzu, binciken Davis da Scantlebury ya kai ga gano cikakkun takaddun bincike da wani Ba'amurke ya yi wanda ya zo da irin wannan ra'ayi shekaru da yawa kafin su. Amma a lokaci guda , injiniyan lantarki a Kamfanin RAND, bai yi tunani ko kadan ba game da bukatun masu amfani da kwamfuta na raba lokaci. RAND wata ma'aikatar tsaro ce da ke samar da kuɗin tunani a Santa Monica, California, wanda aka ƙirƙira bayan yakin duniya na biyu don samar da tsari na dogon lokaci da nazarin matsalolin dabarun soja. Burin Baran shine jinkirta yakin nukiliya ta hanyar samar da ingantaccen hanyar sadarwa ta soja wacce zata iya tsira ko da wani babban harin nukiliya. Irin wannan hanyar sadarwa za ta sanya yajin aikin da USSR ke yi ba ta da kyau, tunda zai yi matukar wahala a lalata ikon Amurka na buga maki da yawa don amsawa. Don yin wannan, Baran ya ba da shawarar tsarin da ya karya saƙonni zuwa cikin abin da ya kira tubalan saƙo waɗanda za a iya watsa su kai tsaye a kan hanyar sadarwa na nodes ɗin da ba su da yawa sannan kuma a haɗa su a ƙarshen.
ARPA sun sami damar yin amfani da manyan rahotannin Baran na RAND, amma tunda ba su da alaƙa da kwamfutoci masu mu'amala da su, mahimmancin su ga ARPANET bai fito fili ba. Roberts da Taylor, a fili, ba su taba lura da su ba. Madadin haka, sakamakon haduwar damammaki daya, Scantlebury ya mika komai ga Roberts a kan farantin azurfa: ingantaccen tsarin sauyawa, dacewa ga matsalar ƙirƙirar hanyoyin sadarwa na kwamfuta, kayan tunani daga RAND, har ma da sunan “kunshin.” Ayyukan NPL kuma sun gamsar da Roberts cewa za a buƙaci ƙarin gudu don samar da iya aiki mai kyau, don haka ya inganta shirinsa zuwa 50 Kbps links. Don ƙirƙirar ARPANET, an warware babban ɓangaren matsala ta hanya.
Gaskiya ne, akwai wani sigar asalin ra'ayin canza fakiti. Daga baya Roberts ya yi iƙirarin cewa ya riga ya sami irin wannan tunani a cikin kansa, godiya ga aikin abokin aikinsa, Len Kleinrock, wanda ake zargin ya bayyana manufar a cikin 1962, a cikin karatun digiri na digiri a kan hanyoyin sadarwa. Duk da haka, yana da matukar wahala a cire irin wannan ra'ayi daga wannan aikin, ban da haka, ban sami wata shaida ga wannan sigar ba.
Hanyoyin sadarwar da ba su wanzu ba
Kamar yadda muke iya gani, ƙungiyoyi biyu sun kasance a gaban ARPA wajen haɓaka fakitin sauya sheka, fasahar da ta tabbatar da inganci wanda a yanzu tana ƙarƙashin kusan dukkanin hanyoyin sadarwa. Me yasa ARPANET ta kasance cibiyar sadarwa ta farko da ta yi amfani da ita?
Yana da duk game da ƙungiyoyin subtleties. ARPA ba ta da izini a hukumance don ƙirƙirar hanyar sadarwar sadarwa, amma akwai ɗimbin cibiyoyin bincike da ke da kwamfutoci nasu, al'adar ɗabi'a na “yanci” waɗanda a zahiri ba a kula da su, da tudun kuɗi. Ainihin buƙatar Taylor na 1966 na neman kuɗi don ƙirƙirar ARPANET ya yi kira ga dala miliyan 1, kuma Roberts ya ci gaba da kashewa a kowace shekara daga 1969 zuwa gaba don haɓaka hanyar sadarwa. A lokaci guda kuma, ga ARPA, irin wannan kuɗin ya kasance ƙananan canji, don haka babu wani daga cikin shugabanninsa da ya damu da abin da Roberts ke yi da shi, idan dai za a iya danganta shi da bukatun tsaron kasa.
Baran a RAND bashi da iko ko ikon yin komai. Ayyukansa na bincike ne kawai da nazari, kuma ana iya amfani da shi don tsaro idan an so. A cikin 1965, RAND ya ba da shawarar tsarinsa ga Rundunar Sojan Sama, wanda ya yarda cewa aikin ya kasance mai yiwuwa. Amma aiwatar da shi ya fada kan kafadu na Hukumar Sadarwar Tsaro, kuma ba su fahimci hanyoyin sadarwa na dijital ba. Baran ya shawo kan manyansa a RAND cewa zai fi kyau a janye wannan shawara maimakon a bar a aiwatar da ita ko ta yaya kuma a lalata sunan sadarwar dijital da aka rarraba.
Davis, a matsayin shugaban NPL, yana da iko fiye da Baran, amma kasafin kuɗi fiye da ARPA, kuma ba shi da hanyar sadarwar zamantakewa da fasaha na kwamfutocin bincike. Ya yi nasarar ƙirƙirar hanyar sadarwar fakiti na gida (akwai kumburi ɗaya kawai amma tashoshi da yawa) a NPL a ƙarshen 1960s, tare da ƙaramin kasafin kuɗi na £ 120 sama da shekaru uku. ARPANET ya kashe kusan rabin wannan adadin kowace shekara kan ayyuka da kiyayewa akan kowane kuɗaɗen cibiyar sadarwa, ban da saka hannun jari na farko a cikin kayan masarufi da software. Kungiyar da ke da ikon samar da babbar hanyar musayar fakiti ta Burtaniya ita ce Ofishin gidan waya ta Burtaniya, wacce ke kula da hanyoyin sadarwar sadarwa a cikin kasar, sai dai na gidan waya da kanta. Davis ya gudanar da sha'awar jami'ai masu tasiri da yawa tare da ra'ayoyinsa don haɗin kai na hanyar sadarwa na dijital a kan sikelin kasa, amma ya kasa canza alkiblar irin wannan babbar tsarin.
Licklider, ta hanyar haɗin sa'a da tsare-tsare, ya sami cikakkiyar greenhouse inda cibiyar sadarwa ta intergalactic zata iya bunƙasa. A lokaci guda, ba za a iya cewa komai ba sai dai canza fakiti ya sauko zuwa kuɗi. Har ila yau, aiwatar da ra'ayin ya taka rawa. Haka kuma, wasu mahimman shawarwarin ƙira da yawa sun tsara ruhun ARPANET. Don haka, a gaba za mu duba yadda aka raba alhaki tsakanin kwamfutocin da suka aika da sakonni, da kuma hanyar sadarwar da suka aika wadannan sakonni.
Me kuma za a karanta
- Janet Abbate, Ƙirƙirar Intanet (1999)
- Katie Hafner da Matthew Lyon, Inda Wizards suka tsaya Late (1996)
- Leonard Kleinrock, "Tarihin Farko na Intanet," Mujallar Sadarwar IEEE (Agusta 2010)
- Arthur Norberg da Julie O'Neill, Canza Fasahar Kwamfuta: Gudanar da Bayani don Pentagon, 1962-1986 (1996)
- M. Mitchell Waldrop, Injin Mafarki: JCR Licklider da Juyin Juya Halin da Ya Yi Kwamfuta Na Musamman (2001)
source: www.habr.com