file output bug?

[ferrante@world.std.com (Richard D Ferrante)]

I don't know if this is the appropriate forum for bug reports but I
seem to have found a bug in MCL2.0b1.
When I overwrite an existing file with a shorter one, a portion of the
previous file MAY remain at the end of the new file.

For example
------
(with-open-file (out-stream hist-file
                                :direction :output :if-exists
                                :new-version)
      (format out-stream "HISTOGRAM DATA Mean ~a std ~a  total samples
                           ~a" mean std samples)
      (loop for i from 0 below *bin-count*
            do
            (format out-stream "~% ~a, ~a" i (aref *bin-array* i) )))
-----
Changing *bin-count* from 400 to 100 resuted in a file of 134 samples

Deleting the old file (from the finder) eliminated the problem.

Possibly useful information:
Quantum PD210S Drive, 512bytes/sector
System 7.0
--- 

Richard Ferrante
(617)-739-7055
ferrante@world.std.com