File - read from EOF

[JB]

I want to read a file as binary of any
size but as crazy as it sounds I want
to read in sections form the EOF and
stop at the beginning of the file instead
reading from the start to EOF.

I have no problems opening, reading and
closing files or reading in sections.

Does anyone know the easiest way
to determine when I reach the start
of the file similar to using EOF to
stop reading at the end of the file?

JB