(as in a "hole" in system memory):
When DOS is starting; it begins allocating areas of memory below 640 K, which are used to store information. There are some places where there are gaps in the allocated memory. These gaps are unallocated and unused, and they are considered to be "holes" in system memory. A hole in system memory may also be created in DOS because as DOS loads programs, it often rounds off the amount of memory allocated to the program. For example, a program might need 1025 Bytes (1Kb + 1 Byte). When DOS loads this program, it may allocate 2Kb of memory for the program. Thus