A double sided magnetic disk pack has six disks. Can you tell how many surfaces of this pack are normally used? A. 10 B. 12 C. 6 D. 9 E. None of the above
Extreme surfaces of the disk are more prone to external damage or scratches from outer casing. Due to this, almost all the manufacturers do not use them for recording. Upper layer of first disk and lower layer of last disk is not used, 12 - 2 = 10 surfaces.
