Charles G Waldman <cgw(a)pgt.com> writes in xemacs-beta(a)xemacs.org:
 Currently, "hexl-find-file" does not work on WinNT.
 "hexl.el" contains the following: 
 (defun hexl-find-file (filename)
   "Edit file FILENAME in hexl-mode.
 Switch to a buffer visiting file FILENAME, creating one in none exists."
   (interactive "fFilename: ")
   (if (or (eq system-type 'ms-dos) (eq system-type 'windows-nt))
       (find-file-binary filename)
     (find-file filename))
   (if (not (eq major-mode 'hexl-mode))
       (hexl-mode))) 
 However, the function "find-file-binary", AFAICT, is not
defined
 anywhere - not in any of the package lisp, or the XEmacs base source,
 which I have been furiously grepping through for the last half-hour. 
 Of course, I'm probably overlooking something obvious.  Where is
this
 function supposed to be defined? 
This isn't going to work right in Unix either.  Drop the conditional,
and wrap the `find-file' call with something like:
(let ((buffer-file-coding-system 'binary))
  (find-file filename))
Does that work a bit better?