Kalmar "motherboard" tana nufin babban allon da'ira na kwamfuta, wanda ke ginawa da kuma haɗa dukkan abubuwan da ke cikinta. Hakanan ana kiranta da babban allo, allon tsarin, ko allon tunani. Motherboard tana ba da dandamali don CPU, RAM, na'urorin ajiya, katunan faɗaɗawa, da sauran na'urori masu alaƙa don sadarwa tare da juna da aiki azaman tsarin haɗin gwiwa. Hakanan yana ƙunshe da nau'ikan haɗin kai da tashoshin jiragen ruwa, kamar tashoshin USB, jacks, da tashoshin Ethernet, don na'urorin waje don haɗawa da kwamfutar.