When they are planning how to organize their IO , programs (and designers) normally assume thatrewriting (overwriting) an existing, already written file is the fastestsort of write operation possible and will not change the existing filelayout (for example, if it has been created to be sequential). Thisis because all of the data blocks have already been allocated and allof the metadata has been set up; if you write in block-aligned units,pretty much all the operating system has to do is shovel