Esta informacion la encontre en el link que dejo abajo... esto aclara la interrogante que se presento, pero basicamente su uso se explica en comentarios anteriores, Saludos.
(Beginning Of File) The status of a file when it is first opened or when an instruction or command has reset the file pointer.
http://computing-dictionary.thefreedictionary.com/BOF
(End Of File) The status of a file when its end has been reached or when an instruction or command resets the file pointer to the end.
http://computing-dictionary.thefreedictionary.com/EOF