Izinga le-ASCII lamukelwa ngo-1963, futhi manje akukho muntu osebenzisa umbhalo wekhodi onezinhlamvu zokuqala ezingu-128 ezihlukile ku-ASCII. Kodwa-ke, kuze kube sekupheleni kwekhulu leminyaka elidlule, i-EBCDIC yayisetshenziswa ngenkuthalo - ukubhala ngekhodi okujwayelekile kwe-IBM mainframes kanye namakhompyutha abo e-Soviet clones EC. I-EBCDIC isalokhu ingumbhalo wekhodi oyinhloko ku-z/OS, isistimu yokusebenza evamile yozimele abakhulu besimanje be-IBM Z.
Okubamba iso lakho ngokushesha uma ubheka i-EBCDIC ukuthi izinhlamvu azilandelani: phakathi I и J naphakathi R и S bekunezikhundla ezingasetshenzisiwe (kukhompuyutha ye-ES kulezi zikhathi Izinhlamvu zesiCyrillic). Ubani obengacabanga ukufaka izinhlamvu ezinezikhala ezingalingani phakathi kwezinhlamvu ezincikene?
Lona kanye igama elithi EBCDIC (“I-BCDIC Enwetshiwe”) lisikisela ukuthi lokhu kubhala ngekhodi - ngokungafani ne-ASCII - akuzange kudalwe kusukela ekuqaleni, kodwa kusekelwe ekubhaleni ngekhodi kwe-BCDIC enamabhithi ayisithupha, osekusetshenziswe kusukela ngaleso sikhathi. (1954):
Akukho ukuvumelana okubuyela emuva ngokushesha: isici esikahle se-BCDIC esalahleka ekushintsheleni ku-EBCDIC kwakuwukuthi izinombolo 0-9 ahambisana namakhodi 0-9. Nokho, kukhona izikhala amakhodi ayisikhombisa phakathi I и J kanye namakhodi ayisishiyagalombili phakathi R и S vele ngiye ku-BCDIC. Bavelaphi?
Umlando we-(E)BCDIC uqala kanyekanye nomlando we-IBM - kudala ngaphambi kwamakhompyutha kagesi. I-IBM yasungulwa ngenxa yokuhlanganiswa kwezinkampani ezine, okukhona kuzo ezithuthuke kakhulu kwezobuchwepheshe iTabulating Machine Company, eyasungulwa ngo-1896 nguHerman Hollerith, umsunguli. . Amathebula okuqala avele abala inani lamakhadi abhontshiwe ashaywa endaweni ethile; kodwa ngo-1905 uHollerith waqala ukukhiqiza idesimali ama-tabulators. Ikhadi ngalinye lethabulatha ledesimali lalihlanganisa izinkambu zobude obungalingani, futhi izinombolo ezibhalwe kulezi zindawo ngendlela yedesimali evamile zafingqwa phezu kwedekhi yonke. Ukuhlukaniswa kwemephu ibe izinkambu kwanqunywa ngokuxhuma izintambo kuphaneli yesichibi se-tabulator. Isibonelo, kuleli khadi le-punch ye-Hollerith, kuMtapo Wolwazi WeCongress, inombolo ethi 23456789012345678 igxivizwe ngokucacile, akwaziwa njengehlukaniswe izinkambu:
Abanake kakhulu kungenzeka ukuthi baye baqaphela ukuthi ebalazweni laseHollerith kunemigqa engu-12 yezimbobo, nakuba eziyishumi zanele izinombolo; futhi ku-BCDIC, ngevelu ngayinye yamabhithi amabili abaluleke kakhulu, amakhodi ayi-12 kuphela asetshenziswa kwayi-16 okungenzeka.
Yiqiniso, lokhu akukhona ukuqondana nje. Ekuqaleni, u-Hollerith wayehlose imigqa eyengeziwe “yamamaki akhethekile” ayengahlanganiswa, kodwa abalwe nje - njengakumathebula okuqala. (Namuhla sizobabiza ngokuthi “bit fields”.) Ngaphezu kwalokho, phakathi “kwamamaki akhethekile” kwakungenzeka ukusetha izinkomba zeqembu: uma ukuhlelwa kwethebula kungadingi izibalo zokugcina kuphela, kodwa futhi naphakathi, khona-ke i-tabulator izomisa lapho ithole ushintsho kunoma yiziphi izinkomba zeqembu , futhi u-opharetha kwadingeka abhale kabusha amanani amancane asuka kumabhodi edijithali ephepheni, asethe kabusha ibhodi, futhi aqalise kabusha ukufakwa kwethebula. Isibonelo, lapho kubalwa amabhalansi okubalwa kwezimali, iqoqo lamakhadi lingahambisana nedethi eyodwa noma elinye iqembu.
Ngo-1920, lapho u-Hollerith eseyekile kakade umhlalaphansi, kwaqala ukusetshenziswa “ama-tabulators okuthayipha,” ayexhunywe kuhlobo lwe-teletype futhi ayekwazi ukuzinyathelisa ngokwawo ama-subtotal ngaphandle kokudinga ukungenelela komsebenzisi. Ubunzima manje kwakuwukunquma ukuthi inombolo ngayinye enyathelisiwe yayibhekiselwa kuphi. Ngo-1931, i-IBM yanquma ukusebenzisa "amamaki akhethekile" ukukhombisa izinhlamvu: uphawu emgqeni we-12 lubonisa uhlamvu oluvela. A ukuze I, ngo-11 - kusukela J ukuze R, ngoziro - kusuka S ukuze Z. "I-tabulator yezinhlamvu" entsha ingaphrinta igama leqembu ngalinye lamakhadi kanye namathothali amancane; kulesi simo, ikholomu enganqamuki iphenduke yaba isikhala phakathi kwezinhlamvu. Sicela uqaphele lokho S iqokwa ngenhlanganisela yembobo engu-0+2, futhi inhlanganisela engu-0+1 ayizange isetshenziswe ekuqaleni ngenxa yokwesaba ukuthi izimbobo ezimbili eduze kwenye kukholamu efanayo zingabangela izinkinga zemishini kumfundi.
Manje ungabheka ithebula le-BCDIC nge-engeli ehluke kancane:
Ngaphandle kokuthi u-0 nesikhala kubuyiselwe emuva, izingcezu ezimbili ezibaluleke kakhulu zichaza "uphawu olukhethekile" olufakwe ekhadini le-punch lomlingiswa ohambisanayo kusukela ngo-1931; futhi izingcezu ezine ezingabalulekile zinquma idijithi ephonswe engxenyeni eyinhloko yekhadi. Ukusekelwa kwezimpawu & - / yengezwe kumathebula e-IBM ngeminyaka yawo-1930, futhi umbhalo we-BCDIC walezi zinhlamvu uhambisana nezinhlanganisela zembobo ezibethelwe zona. Lapho kudingeka ukusekelwa kwenani elikhulu nakakhulu lezinhlamvu, umugqa wesi-8 wawushaywa “njengophawu olukhethekile” olwengeziwe - ngaleyo ndlela, kungase kube nezimbobo ezifinyelela kwezithathu kukholamu eyodwa. Le fomethi yamakhadi ashaywayo yahlala ingashintshile kwaze kwaba sekupheleni kwekhulu leminyaka. E-USSR, bashiye umbhalo we-IBM wesiLatini kanye nezimpawu zokubhala, futhi ngezinhlamvu zesiCyrillic bashaya "amamaki akhethekile" amaningana ngesikhathi esisodwa emigqeni 12, 11, 0 - engagcini ngezimbobo ezintathu kukholamu eyodwa.
Lapho ikhompyutha ye-IBM 704 idalwa, abazange bacabange isikhathi eside mayelana nombhalo wekhodi wayo: bathatha umbhalo wekhodi owawuvele usetshenziswe emakhadini ashaywayo ngaleso sikhathi, futhi kuphela "wawubeka endaweni yawo." Ngo-0, ngesikhathi soguquko lusuka ku-BCDIC luye ku-EBCDIC, izingcezu ezine ezine-oda eliphansi zophawu ngalunye zashiywa zingashintshiwe, nakuba izingcezu ezisezingeni eliphezulu zashiyizwa kancane. Ngakho-ke, ifomethi yekhadi elihlatshiwe elikhethwe ngu-Hollerith ekuqaleni kwekhulu leminyaka elidlule libe nomthelela ekwakhiweni kwawo wonke amakhompyutha e-IBM, kuze kufike ku-IBM Z.
Source: www.habr.com