In magnetic disc access; to subdivide sectors by timing pulses between sector marks; a facility to permit accessing locations smaller than sectors.; 在磁盤存取中,用定時(shí)［同步］脈沖將扇區(qū)標(biāo)記間的扇形區(qū)再劃分;允許訪問單元小于扇形區(qū) 的一種功能。