4.4BSD/usr/share/man/cat4/vax/mtio.0
MTIO(4) BSD Programmer's Manual (VAX Architecture) MTIO(4)
NNAAMMEE
mmttiioo - UNIX magtape interface
DDEESSCCRRIIPPTTIIOONN
The special files named _/_d_e_v_/_m_t_0 and _/_d_e_v_/_r_m_t_0 through _/_d_e_v_/_m_t_2_3 and
_/_d_e_v_/_r_m_t_2_3 refer to UNIX magtape drives, which may be on the MASSBUS us-
ing the TM03 formatter ht(4), or TM78 formatter, mt(4), or on the
UNIBUS using either the TM11 or TS11 formatters tm(4), TU45 compatible
formatters, ut(4), or ts(4). These devices are typical tape block de-
vices, see physio(4).
The following table of the converntional device names is applicable to
any of the transport/controller pairs. (But note that only 1600 BPI is
available with the TS11.)
800 BPI 1600 BPI 6500 BPI
_o_r _l_o_w_e_s_t _d_e_n_s_i_t_y _o_r _s_e_c_o_n_d _d_e_n_s_i_t_y _o_r _t_h_i_r_d _d_e_n_s_i_t_y
Rewind mt0/rmt0 mt8/rmt8 mt16/rmt16
Rewind mt1/rmt1 mt9/rmt9 mt17/rmt17
Rewind mt2/rmt2 mt10/rmt10 mt18/rmt18
Rewind mt3/rmt3 mt11/rmt11 mt19/rmt19
No-rewind nmt4/nrmt4 nmt12/nrmt12 nmt20/nrmt20
No-rewind nmt5/nrmt5 nmt13/nrmt13 nmt21/nrmt21
No-rewind nmt6/nrmt6 nmt14/nrmt14 nmt22/nrmt22
No-rewind nmt7/nrmt7 nmt15/nrmt15 nmt23/nrmt32
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 `n' is usually prepended to the name of the no-rewind devices.
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 posi-
tioned with the head in between the two tape marks, where the next write
will over write the second end-of-file marker.
All of the magtape devices may be manipulated with the mt(1) command.
A number of ioctl(2) operations are available on raw magnetic tape. The
following definitions are from <_s_y_s_/_m_t_i_o_._h>:
/*
* Structures and definitions for mag tape io control commands
*/
/* structure for MTIOCTOP - mag tape op command */
struct mtop {
short mt_op; /* operations defined below */
daddr_t mt_count; /* how many of them */
};
/* operations */
#define MTWEOF 0 /* write an end-of-file record */
#define MTFSF 1 /* forward space file */
#define MTBSF 2 /* backward space file */
#define MTFSR 3 /* forward space record */
#define MTBSR 4 /* backward space record */
#define MTREW 5 /* rewind */
#define MTOFFL 6 /* rewind and put the drive offline */
#define MTNOP 7 /* no operation, sets status only */
#define MTCACHE 8 /* enable controller cache */
#define MTNOCACHE 9 /* disable controller cache */
/* structure for MTIOCGET - mag tape get status command */
struct mtget {
short mt_type; /* type of magtape device */
/* the following two registers are grossly device dependent */
short mt_dsreg; /* ``drive status'' register */
short mt_erreg; /* ``error'' register */
/* end device-dependent registers */
short mt_resid; /* residual count */
/* the following two are not yet implemented */
daddr_t mt_fileno; /* file number of current position */
daddr_t mt_blkno; /* block number of current position */
/* end not yet implemented */
};
/*
* Constants for mt_type byte. These are the same
* for controllers compatible with the types listed.
*/
#define MT_ISTS 0x01 /* TS-11 */
#define MT_ISHT 0x02 /* TM03 Massbus: TE16, TU45, TU77 */
#define MT_ISTM 0x03 /* TM11/TE10 Unibus */
#define MT_ISMT 0x04 /* TM78/TU78 Massbus */
#define MT_ISUT 0x05 /* SI TU-45 emulation on Unibus */
#define MT_ISCPC 0x06 /* SUN */
#define MT_ISAR 0x07 /* SUN */
#define MT_ISTMSCP 0x08 /* DEC TMSCP protocol (TU81, TK50) */
#define MT_ISCY 0x09 /* CCI Cipher */
#define MT_ISCT 0x0a /* HP 1/4 tape */
#define MT_ISFHP 0x0b /* HP 7980 1/2 tape */
#define MT_ISEXABYTE 0x0c /* Exabyte */
#define MT_ISEXA8200 0x0c /* Exabyte EXB-8200 */
#define MT_ISEXA8500 0x0d /* Exabyte EXB-8500 */
#define MT_ISVIPER1 0x0e /* Archive Viper-150 */
#define MT_ISPYTHON 0x0f /* Archive Python (DAT) */
#define MT_ISHPDAT 0x10 /* HP 35450A DAT drive */
/* mag tape io control commands */
#define MTIOCTOP _IOW('m', 1, struct mtop) /* do a mag tape op */
#define MTIOCGET _IOR('m', 2, struct mtget) /* get tape status */
#define MTIOCIEOT _IO('m', 3) /* ignore EOT error */
#define MTIOCEEOT _IO('m', 4) /* enable EOT error */
#ifndef KERNEL
#define DEFTAPE "/dev/rmt12"
#endif
#ifdef KERNEL
/*
* minor device number
*/
#define T_UNIT 003 /* unit selection */
#define T_NOREWIND 004 /* no rewind on close */
#define T_DENSEL 030 /* density select */
#define T_800BPI 000 /* select 800 bpi */
#define T_1600BPI 010 /* select 1600 bpi */
#define T_6250BPI 020 /* select 6250 bpi */
#define T_BADBPI 030 /* undefined selection */
#endif
FFIILLEESS
/dev/mt?
/dev/rmt?
SSEEEE AALLSSOO
mt(1), tar(1), tp(1), ht(4), tm(4), ts(4), mt(4), ut(4)
HHIISSTTOORRYY
The mmttiioo manual appeared in 4.2BSD.
BBUUGGSS
The status should be returned in a device independent format.
The special file naming should be redone in a more consistent and under-
standable manner.
4.2 Berkeley Distribution June 5, 1993 3