pace allocation for files. When the size of allocation unit is 32768 bytes, a file with 100 bytes in size occupies 32768 bytes of disk space. The space efficiency of disk usage gets worse as increasing size of allocation unit, but, on the other hand, the read/write performance increases as the size of allocation unit. Therefore the allocation unit is a trade-off between space efficiency and performance. For the large storages in GB order, 32768 bytes or larger cluster (this is automatically selected by defa