Linus Benedict Torvalds waa injineer software Finnish-Maraykan ah, oo caan ku ah bilaabista iyo ilaalinta horumarinta kernel Linux,
Maalmo ka hor Linus Torvalds waxa uu ka dhigay ra'yigiisa ku saabsan joojinta taageerada naqshadaha processor-ka i486 ee Linux kernel. Nashqadii hore ayaa maalmo ka hor looga hadlay dunta lagu eegayo sida kernelku uu u maarayn karo liisaska ugu yar ee dhowaan la isticmaalay (LRU), hab lagula socdo bogagga xusuusta.
Iyadoo Torvalds ayaa baadhay koodka Iskaashatada, waxaad mooddaa inay ka xumaatay baahida loo qabo in xal lagu daro ku filan CPU-yada da'da weyn. Sidaa darteed, wuxuu soo jeediyay in la joojiyo taageerada qalabkii hore, taas oo noqon karta hab sahlan oo lagu hagaajinayo arrimaha xusuusta.
"Waxaan ka takhalusnay taageerada i386 2012. Ma laga yaabaa in la joogo waqtigii la joojin lahaa taageerada i486 2022? Linus Torvalds ayaa yidhi
Waxaan horeyba u sameynay (la qiran yahay qalad: maaha SMP-ammaan, ie si fiican ayey u shaqeyn doontaa xitaa marka lala kulmo marin isku mar ah oo laga helo taxane badan oo fulin ah, laakiin mashiinnada SMP Class 486 waligood lama taageerin in kasta oo ay farsamo ahaan jireen)
Waa in la xasuustaa taas taxanaha i486 CPU waxaa la sii daayay 1989kii oo hadda aad u yar qaybinta Linux sida Gentoo, Slackware iyo KNOPPIX waxay sii wadaan inay taageeraan dhismahan.
Sida laga soo xigtay Torvalds, dhibaatooyinka ay keenaan taageeridda naqshadaha duugoobay ee ay dad yar isticmaalaan waxaa laga yaabaa inay u sahlanaato inay xalliyaan iyagoo meesha ka saaraya taageeradooda. Maareynta xusuusta LRU ee soo-saareyaashii hore waxay sidoo kale noqon doontaa kiiskan oo kale.
Daacadnimo, dhib kama qabo inaan u cusboonaysiiyo shuruudaha ugu yar ee loo baahan yahay ugu yaraan M586TSC, anigoo ka tagaya qaar ka mid ah kuwa hore ee "Pentium been-abuurka ah" sidoo kale. Sababtoo ah 'rdtsc' waxay u badan tahay inay tahay dhibaato ka sii daran CMPXCHG8B.
Waa sidaas Dhammaantood waxay hoos ugu dhacaan cmpxchg8b, tilmaame isbarbar dhigaya ka dibna isku beddelaya siddeed bytes (ama 64 bits) oo ah macluumaadka ku jira xusuusta kombiyuutarka. Xubin ka tirsan liiska boostada Peter Zijlstra ayaa soo jeediyay in Linux ay tahay inay taageerto kaliya soo-saareyaasha awooda inay tan sameeyaan, iyagoo ka tagaya 486-bit i32 gadaasha iyo macnaha in kernels Linux cusub ay ku shaqeyn doonaan qalabka fasalka P5 ama ka cusub.
Tilmaamaha cmpxchg8b waa dambiilaha khaladka 'F00F' laga bilaabo Pentium-kii asalka ahaa, kaas oo ay saamaysay CPU iyada oo aan la dhimin nidaamka qalliinka uu joojiyay shaqada ilaa dib loo bilaabo markii lagu dhiirigeliyo fulinta tilmaamaha.
Dhab ahaantii, ma fahmin gabi ahaanba sababta kernels hadda ay ugu shaqeeyaan i486, maadaama ay u egtahay ka bixista_user_mode_prepare -> arch_exit_to_user_mode_prepare, oo ay ku dhamaato in la haysto qoraal 'rdtsc' shuruud la'aan ah.
Waxaan u malaynayaa inaadan awood u siin.RANDOMIZE_KSTACK_OFFSET*? Si kale haddii loo dhigo, saxaafadeena aan Pentium ahayn hadda aad bay u cilladaysan tahay oo way u jajaban tahay.
Sida laga soo xigtay isaga, Waxaa shaki weyn laga qabaa in qalabka i486 uu weli ku habboon yahay. Shaki kuma jiro in ay wali dunida ku jiraan dad go’aan qaadasho leh, kuwaas oo aaminsan in dhibaatooyinka ka dhasha si fudud looga gudbi karo, laakiin laga soo bilaabo aragtida horumarinta kernel, booskani maaha mid dhab ah.
"Marka runtii uma maleynayo in qalabka i486-class uu mar dambe khuseeyo. Haa, waan hubaa inay jiraan (Maciej waa tusaale), laakiin dhanka horumarka kernel-ka, uma malaynayo inay runtii khuseeyaan. Mararka qaarkood, dadku waxay u haystaan inay yihiin qaybo madxaf. Waxay kaloo maamuli karaan xudunta u ah madxafyada.
Waa in la sheegaa in dhismaha i486 waxa la soo bandhigay 1989 waxana lagu badalay Pentium Intel 1993kii. Intel waxay ka takhalustay i486 sannadkii 2007-dii maantana caan ku ah xogta tafaasiisha alaabta Ark kuma jirto wax lagu sheego qoyska processor-ka.
Kuwa wali isticmaala aaladaha wakhti hore ka hor waxay iska casileen inay sidaas sameeyaan iyaga oo aan helin taageero, iyada oo aan suurtagal ahayn in ay helaan qalab cusub ama kuwa soo saara software-ka ayaa ka fikiray goobta.
Faahfaahin dheeraad ah, Intel 80486 (i486, 486) waa microprocessor qoyska x86, oo ay soo saartay Intel. Waxaa la sii daayay 1989. Marka la eego naqshadeynta processor-ka, 80486 wuxuu aad ugu eg yahay kii ka horreeyay, Intel 80386, oo lagu daray dhowr tilmaamood oo dheeri ah. Sidaa darteed, waa naqshad CISC ah.
Marka laga eego aragtida farshaxan-gacmeedka yar-yar, waxaa jiray horumar weyn wakhtigaas: waxbarid midaysan oo la isku daray iyo khasnado xogta, unugga habaynta barta Floating Point (FPU), iyo isdhexgalka baska oo la hagaajiyay.
Ugu dambayntii waxa uu xusay Isticmaalayaasha leh nidaamyada leh processor-rada i486 waxay awoodi doonaan inay isticmaalaan noocyada LTS ee kernel-kakaas oo socon doona sanado badan oo soo socda.
Taageerada moodooyinka qadiimka ah ee soo-saareyaasha iyo aaladaha waxaa laga yaabaa in laga saaro kernel Linux sababo kala duwan, sida fududaynta iyo tayaynta koodka, yaraynta kakanaanta kernel-ka iyo dayactirka, ama diiradda saaraya aalado badan oo casri ah oo caan ah. Tusaalooyinka qaar ka mid ah moodooyinka hore ee laga saari karo taageerada kernel Linux waxaa ka mid ah:
Soo-saareyaashii hore: sida Intel i386, i486, ama qaar ka mid ah processor-rada AMD ee da'da ah. Soo-saareyaashani aad bay u da'weyn yihiin mana taageeraan sifooyinkii ugu dambeeyay ee kernel-ka Linux.
Aaladaha durugsan ee qadiimiga ah: Sida cajalado, floppy drives, ama cod gaboobay ama kaarar muuqaal ah. Aaladan maanta aad uma badna, sidaas darteed taageerada iyaga ayaa laga yaabaa in lagala noqdo si loo yareeyo kakanaanta kernel-ka.
Farsamooyinka duugoobay: sida taageerada hab-maamuuska shabakadda IPX, kaas oo caadi ahaan loo isticmaali jiray shabakadaha kombuyuutarka tobanaan sano ka hor. Marka ay tignoolajiyadu horumarto oo ay is beddesho, taageerada tignoolajiyada burburay ayaa laga yaabaa in laga saaro kernel-ka.