FWIW, the canonical change to DOS 3.3 to make it *very* tolerant of altered address and data marks (within limits) is: B942:18 This changes a catchall error return (SEC, RTS) into CLC, RTS, which, surprisingly, often renders a mildly copy-protected disk quite easily read and COPYAed by a normal DOS 3.3. -michael Email: mjmahon@aol.com Home page: http://members.aol.com/MJMahon/