MTIO -- Magtape i/o.  This directory contains the FIO device driver for the
magtape devices plus MTOPEN (used to open a magtape device and hook it to
FIO) plus a few other routines.  See ./doc for additional info.


USER ROUTINES

		yes|no = mtfile (fname)		# Is fname a magtape device?
	  yes|no = mtneedfileno (mtname)	# No file number given?
		    gty = mtcap (mtname)
			mtfname (mtname, file, outstr, maxch)

		        mtparse (mtname, device, fileno, recno, attrl, maxch)
		       mtencode (mtname, maxch, device, fileno, recno, attrl)

		    fd = mtopen (mtname, acmode, bufsize)
		       mtrewind (mtname, initcache)
		     mtposition (mtname, file, record)

	Use CLOSE to close a file descriptor opened with mtopen.
	Use GTYCLOSE to close a termcap descriptor opened with mtcap.
	MTNAME is the full magtape device specification, i.e, "mt[...]".



SYSTEM ROUTINES

		     mtallocate (mtname)
		   mtdeallocate (mtname, rewind_tape)
		       mtstatus (out, mtname)
		        mtclean (level, stale, out)



FIO DRIVER

			 zopnmt (iodev, acmode, mtchan)
			 zclsmt (mtchan, status)
			 zardmt (mtchan, buf, maxbytes, offset)
			 zawrmt (mtchan, buf, nbytes, offset)
			 zawtmt (mtchan, status)
			 zsttmt (mtchan, what, lvalue)


All other procedures are internal to the interface.