“Data in the computer is stored in files that are written on the hard disk which is like a giant closet with millions of drawers and each drawer has the same capacity (usually 512 bytes). If the data is stored in contiguous drawers, it can be accessed faster than if it was in a discontinuous (fragmented) order into the closet. So far, it is understood that “things” can be found faster in an ordered closet than in a messy one. The problem is to know how to keep the closet organized when it is frequently used.”