Fayil ɗin diski nau'in fayil ne na kwamfuta wanda ke adanawa a kan rumbun kwamfutarka ko wata na'ura ta waje. Yawanci ya ƙunshi jerin bayanan bytes waɗanda za a iya karantawa daga ko rubuta zuwa faifai. A cikin kwamfuta, kalmar "disk" yawanci tana nufin faifan maganadisu, kamar faifan diski, wanda zai iya adana bayanai masu yawa. Kalmar “fayil” tana nufin tarin bayanai masu alaƙa waɗanda aka adana a matsayin guda ɗaya akan faifai. Don haka, fayil ɗin diski shine kawai fayil ɗin da aka adana akan faifai.