Thaum kawm txog chav kawm keeb kwm hauv computer, ib qho yuav tsum daws cov teeb meem ntawm kev nrhiav cov ntaub ntawv khaws cia ntawm cov cab kuj lossis kis tau los ntawm kev sib txuas lus channel rau lub sijhawm. Cov koog rau ntsuas cov nqi ntawm cov ntaub ntawv yog me ntsis, nibble, byte, lo lus, ob lo lus thiab lawv cov derivatives.
Cov Lus Qhia
Kauj ruam 1
Thaum xam, nco ntsoov tias ib nibble yog plaub bits, ate yog yim bits, ib lo lus yog kaum rau, thiab ob lo lus yog peb caug ob. Ib kilobyte yog sib npaug rau 1024 bytes, megabytes - 1024 kilobytes, gigabytes - 1024 megabytes, terabytes - 1024 gigabytes. Ib yam li ntawd, kilobits, megabits, gigabits thiab terabits tau muab txhais ua lwm yam. Cov ntawv me yog txiav txim los ntawm tsab ntawv me “b”, bytes - los ntawm tus niam ntawv loj “B”.
Kauj ruam 2
Txhawm rau tshawb xyuas cov nyiaj ntawm cov ntaub ntawv khaws cia rau hauv ib nrab, ntxiv ua ke qhov ntau ntawm txhua cov ntaub ntawv khaws cia rau nws. Yog tias lawv txhua qhov zoo ib yam, tsuas yog khoo qhov ntim ntawm ib ntawm lawv los ntawm lawv tus lej. Nco ntsoov tias ntawm qee cov ntaub ntawv kaw cia, tag nrho cov ntaub ntawv cia li muab kho kom txog qhov ntev uas tau txiav txim siab ua ntej. Feem ntau nws yog 4096 bytes. Piv txwv li, yog tias muaj plaub cov ntaub ntawv ntawm 30, 50, 58749 thiab 14358 bytes ntawm daim disk, tom qab ntawd lawv qhov loj tag nrho yog 4096 + 4096 + 61440 + 20480 (ob qhov kawg nqi yog tau los ntawm sib ntxiv tus lej 4096 los ntawm 15 thiab 5, ntsig txog), lossis 90112 bytes.
Kauj ruam 3
Xam cov nqi ntawm cov ntaub ntawv xa mus rau ntawm cov kev sib txuas lus channel rau lub sijhawm ntawm lub sijhawm raws li hauv qab no. Txij li cov ntaub ntawv hloov mus rau lwm qhov tau qhia rau hauv me me ib ob thiab lawv cov lus qhia, ua ntej hloov nws mus rau bytes ib ob lossis lawv sib pauv los faib los ntawm 8. Piv txwv, 56 kbps (kilobits ib ob) = 7 kbps (kilobytes ib ob). Tom qab no khoo cov nrawm no los ntawm lub sijhawm qhia ib ob. Piv txwv li, hauv 10 vib nas this ntawm qhov siab ceev saum toj no, 70 KB (kilobytes) yuav kis tau hla lub channel. Yog tias cov ntaub ntawv kis tau los ntawm GPRS thiab tus nqi tsis suav tsis tas, qhov tshwm sim yuav tsum nco ntsoov muab suav kom txog qhov pib ntawm qhov chaw muab kev pabcuam. Yog li, yog tias 1 kilobyte kis tau dhau ntawm cov channel zoo li no, thiab qhov pib yog 10 kilobytes, tus nqi hloov pauv xws li ntim ntawm cov ntaub ntawv yuav zoo ib yam rau 10 kilobytes.
Kauj ruam 4
Yog tias qhov ntev ntawm cov ntawv sau hauv cov cim tau teev nyob rau hauv cov xwm txheej ntawm qhov teeb meem, nco ntsoov tias hauv qhov sib txawv ntawm cov cim ib tus coj sib txawv tus lej sib txawv. Nyob rau hauv Baudot code, muaj 5 bits rau ib tus cim, nyob rau hauv ASCII code - 7 (tab sis peculiarities ntawm cov ntaub ntawv khaws cia hauv cov khoom siv ua rau qhov tseeb tias 8 khoom siv rau nws khaws cia), nyob hauv cov ntawv 866, KOI-8P, KOI-8U, 1251 thiab zoo sib xws - 8 me me, thiab hauv Unicode - 16 khoom (tshwj tsis yog rau cov cim los ntawm ASCII lub rooj, uas nyob hauv 8 kab hauv Unicode).
