Lub sijhawm qeeb lossis tom qab ntawd, lub khoos phis tawm ua haujlwm tsis ua haujlwm yog tias tsis muaj kev pabcuam raws sijhawm. Txheeb xyuas cov laj thawj vim li cas lub computer tsis khau khiab, nws yog ib qhov tsim nyog los ua qee yam ntawm cov txheej txheem.
Feem ntau, lub khoos phis tawm tsis vim yog ua haujlwm tsis zoo ntawm lub operating system. Muaj ntau ntau ntawm cov laj thawj. Feem ntau feem ntau, qhov teeb meem tshwm sim vim kev teeb tsa ntawm cov khoom siv tsis tau tsav tsheb. Qhov no tuaj yeem kho tau yooj yim los ntawm kev rov qab kho dua tshiab rau kev ua haujlwm dhau los rau lub xeev yav dhau los. Qee zaum cov teeb meem tuaj yeem tshwm sim vim kev ua tsis ncaj ntawm lub operating system boot files. Qhov no ua rau muaj qhov tseeb tias qee cov cuab yeej tsis tau txais cov lus txib tseem ceeb, vim qhov ua haujlwm ntawm lub operating system tsis tuaj yeem thauj khoom kom raug. Hauv qhov no, nws raug pom zoo kom siv cov kev siv tshwj xeeb thiab cov haujlwm uas tso cai rau koj los tsim cov ntaub ntawv khau raj tshiab. Ntau zaus, muaj ntau lub sijhawm thaum lub computer tsis hlawv tom qab kev sib txuas tsis yog lossis teeb tsa kev ua haujlwm ntawm qee lub khoom siv. Yog tias lub koos pis tawj tseem ceeb tau teem rau lub DVD tsav, thiab lub hard disk yuav tsis txhua nyob rau hauv cov npe ntawm cov khoom siv khau raj, tom qab ntawd yuav muaj qee qhov teeb meem nrog kev pib ua haujlwm. Ntau zaus, cov laj thawj uas tsis muaj peev xwm khau lub koos pis tawj yog qhov tsis ua tiav ntawm ib lossis ntau ntawm nws cov ntsiab lus. Hauv qhov no, nws yog qhov nyuaj los txheeb xyuas qhov tshwj xeeb ntawm tus neeg tsis ua haujlwm. Feem ntau, cov cuab yeej txuas hauv qab no tsis ua hauj lwm raug: lub chaw xa hluav taws xob, qee cov ntsiab lus ntawm qhov system board, ib qho nyuaj tsav thiab RAM tuav. Nws tsim nyog sau cia tias cov tsos mob tshwm sim thaum lub khoos phis tawj tsis khau tsis raug yuav yog ntau yam. Feem ntau, ua tsaug rau lawv, nws yog qhov ua tau sai sai kom paub qhov ua rau muaj teeb meem thiab rov qab ua haujlwm ntawm lub PC. Hmoov tsis zoo, hauv qee qhov xwm txheej, ib lossis ntau cov khoom siv yuav tsum tau hloov kom thiaj li ua tiav lub computer, uas ua rau qee cov nqi nyiaj txiag.
