.\"	$OpenBSD: mtio.4,v 1.14 2007/05/31 19:19:51 jmc Exp $
.\"	$NetBSD: mtio.4,v 1.4 1996/03/03 17:13:54 thorpej Exp $
.\"
.\" Copyright (c) 1983, 1991 The Regents of the University of California.
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.\"     from: @(#)mtio.4	6.5 (Berkeley) 3/27/91
.\"
.Dd $Mdocdate: May 31 2007 $
.Dt MTIO 4
.Os
.Sh NAME
.Nm mtio
.Nd magtape interface
.Sh SYNOPSIS
.Fd #include <sys/mtio.h>
.Sh DESCRIPTION
This interface concerns devices which are typical tape block devices,
see
.Xr physio 9 .
.Pp
The conventional device letters/numbers
is applicable to any of the transport/controller pairs.
(But note that only 1600
.Tn BPI
is available with the
.Tn TS11 ,
and that 800
.Tn BPI
is not applicable to
.Tn TM78 . )
.Pp
When the device last number is between
.Em 0-7
the device will operate at 800
.Tn BPI
(or its lowest density), between
.Em 8-15
it will operate at 1600
.Tn BPI
(or its second density), and between
.Em 16-23
it will operate at 6250
.Tn BPI .
.Pp
The rewind devices automatically rewind
when the last requested read, write or seek has finished, or the end of the tape
has been reached.
The letter
.Ql n
is usually prepended to
the name of the no-rewind devices.
.Pp
Unix tapes are written in multiples of 1024 byte block
records.
Two end-of-file markers mark the end of a tape, and
one end-of-file marker marks the end of a tape file.
If the tape is not to be rewound it is positioned with the
head in between the two tape marks, where the next write
will overwrite the second end-of-file marker.
.Pp
All of the magtape devices may be manipulated with the
.Xr mt 1
command.
.Pp
The include file
.Aq Pa sys/mtio.h
defines the various
.Xr ioctl 2
operations available on raw magnetic tape.
.Sh FILES
.Bl -tag -width /dev/rmt? -compact
.It Pa /dev/mt?
.It Pa /dev/rmt?
.El
.Sh SEE ALSO
.Xr mt 1 ,
.Xr tar 1 ,
.Xr intro 4 ,
.Xr st 4
.Sh HISTORY
The
.Nm
manual appeared in
.Bx 4.2 .
.Sh BUGS
The status should be returned in a device independent format.