A disk for a disk drive including a disk body with a center through hole for fixing the disk body to a turntable formed at a center thereof, a clamping portion formed on the disk body around the center through hole to fix the disk body to the turntable, a signal recording portion which is formed on a surface of the disk body around a rim of the clamping potion and includes a signal recording section on which digital signals are recorded, and crack blocking portions bored through the clamping portion.