Kalmar “allocation unit” yawanci tana nufin mafi ƙarancin adadin sarari a kan rumbun kwamfutar da za a iya warewa don adana bayanai. Har ila yau, wani lokaci ana kiransa “cluster.”Lokacin da aka ajiye fayil ɗin zuwa rumbun kwamfutarka, dole ne a adana shi a cikin guda ɗaya ko fiye, gwargwadon girman fayil ɗin da girman girman fayil ɗin. rabon raka'a. Tsarin aiki na kwamfuta yana lura da waɗanne nau'ikan rarrabawa ake amfani da su da kuma waɗanda ake da su don amfani. Misali, tsarin fayil na FAT32 da yawancin kwamfutocin Windows ke amfani da shi yana da girman juzu'i wanda zai iya tashi daga 512 bytes zuwa 64 kilobytes. Girman girman juzu'in rabon, zai fi dacewa da amfani da ma'ajiya, amma tare da ƙarami girman juzu'i, ƙarancin ɓata sarari wajen adana ƙananan fayiloli.