NAME
mtio — FreeBSD magtape interface
DESCRIPTION
The special files named /dev/[en]sa* refer to SCSI tape drives, which may be attached to the system. /dev/sa*.ctl are control devices that can be used to issue ioctls to the SCSI tape driver to set parameters that are required to last beyond the unmounting of a tape.
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 prepended to the name of the no-rewind devices. The letter ’e’ is prepended to the name of the eject devices.
Tapes can be written with either fixed length records or variable length records. See sa(4) for more information. Two filemarks mark the end of a tape, and one filemark 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 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 <sys/mtio.h>:
#ifndef
_SYS_MTIO_H_
#define
_SYS_MTIO_H_
#ifndef _KERNEL
#include <sys/types.h>
#endif
#include <sys/ioccom.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 */
int32_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 */
#if defined(__FreeBSD__)
/* Set block size for device. If device is a variable size dev
*/
/* a non zero parameter will change the device to a fixed block size
*/
/* device with block size set to that of the parameter passed in.
*/
/* Resetting the block size to 0 will restore the device to a variable
*/
/* block size device. */
#define MTSETBSIZ
10
/* Set density values for device. Sets the value for the opened mode only. */
#define MTSETDNSTY
11
#define MTERASE
12
/* erase to EOM */
#define MTEOD
13
/* Space to EOM */
#define MTCOMP
14
/* select compression mode 0=off, 1=def */
#define MTRETENS
15
/* re-tension tape */
#define MTWSS
16
/* write setmark(s) */
#define MTFSS
17
/* forward space setmark */
#define MTBSS
18
/* backward space setmark */
#define MTLOAD
19
/* load tape in drive */
#define MTWEOFI
20
/* write an end-of-file record without waiting*/
#define MT_COMP_ENABLE
0xffffffff
#define MT_COMP_DISABLED
0xfffffffe
#define MT_COMP_UNSUPP
0xfffffffd
/*
* Values in mt_dsreg that say what the device is doing
*/
#define
MTIO_DSREG_NIL
0
/* Unknown */
#define
MTIO_DSREG_REST
1
/* Doing Nothing */
#define
MTIO_DSREG_RBSY
2
/* Communicating with tape (but no motion) */
#define
MTIO_DSREG_WR
20
/* Writing */
#define
MTIO_DSREG_FMK
21
/* Writing Filemarks */
#define
MTIO_DSREG_ZER
22
/* Erasing */
#define
MTIO_DSREG_RD
30
/* Reading */
#define
MTIO_DSREG_FWD
40
/* Spacing Forward */
#define
MTIO_DSREG_REV
41
/* Spacing Reverse */
#define
MTIO_DSREG_POS
42
/* Hardware Positioning (direction unknown) */
#define
MTIO_DSREG_REW
43
/* Rewinding */
#define
MTIO_DSREG_TEN
44
/* Retensioning */
#define
MTIO_DSREG_UNL
45
/* Unloading */
#define
MTIO_DSREG_LD
46
/* Loading */
#endif
/* __FreeBSD__ */
/* 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 */
/*
* Note that the residual count, while maintained, may be
* be nonsense because the size of the residual may (greatly)
* exceed 32 K-bytes. Use the MTIOCERRSTAT ioctl to get a
* more accurate count.
*/
short
mt_resid;
/* residual count */
#if defined (__FreeBSD__)
int32_t mt_blksiz;
/* presently operating blocksize */
int32_t mt_density;
/* presently operating density */
uint32_t mt_comp;
/* presently operating compression */
int32_t mt_blksiz0;
/* blocksize for mode 0 */
int32_t mt_blksiz1;
/* blocksize for mode 1 */
int32_t mt_blksiz2;
/* blocksize for mode 2 */
int32_t mt_blksiz3;
/* blocksize for mode 3 */
int32_t mt_density0;
/* density for mode 0 */
int32_t mt_density1;
/* density for mode 1 */
int32_t mt_density2;
/* density for mode 2 */
int32_t mt_density3;
/* density for mode 3 */
/* the following are not yet implemented */
uint32_t mt_comp0;
/* compression type for mode 0 */
uint32_t mt_comp1;
/* compression type for mode 1 */
uint32_t mt_comp2;
/* compression type for mode 2 */
uint32_t mt_comp3;
/* compression type for mode 3 */
/* end not yet implemented */
#endif
int32_t
mt_fileno;
/* relative file number of current position */
int32_t
mt_blkno;
/* relative block number of current position */
};
/* structure for
MTIOCERRSTAT - tape get error status command */
/* really only supported for SCSI tapes right now */
struct scsi_tape_errors {
/*
* These are latched from the last command that had a SCSI
* Check Condition noted for these operations. The act
* of issuing an MTIOCERRSTAT unlatches and clears them.
*/
uint8_t io_sense[32];
/* Last Sense Data For Data I/O */
int32_t io_resid;
/* residual count from last Data I/O */
uint8_t io_cdb[16];
/* Command that Caused the Last Data Sense */
uint8_t ctl_sense[32];
/* Last Sense Data For Control I/O */
int32_t ctl_resid;
/* residual count from last Control I/O */
uint8_t ctl_cdb[16];
/* Command that Caused the Last Control Sense */
/*
* These are the read and write cumulative error counters.
* (how to reset cumulative error counters is not yet defined).
* (not implemented as yet but space is being reserved for them)
*/
struct {
uint32_t retries;
/* total # retries performed */
uint32_t corrected;
/* total # corrections performed */
uint32_t processed;
/* total # corrections successful */
uint32_t failures;
/* total # corrections/retries failed */
uint64_t nbytes;
/* total # bytes processed */
} wterr, rderr;
};
union mterrstat {
struct scsi_tape_errors scsi_errstat;
char _reserved_padding[256];
};
struct mtrblim {
uint32_t granularity;
uint32_t min_block_length;
uint32_t max_block_length;
};
typedef enum {
MT_LOCATE_DEST_OBJECT
= 0x00,
MT_LOCATE_DEST_FILE
= 0x01,
MT_LOCATE_DEST_SET
= 0x02,
MT_LOCATE_DEST_EOD
= 0x03
} mt_locate_dest_type;
typedef enum {
MT_LOCATE_BAM_IMPLICIT
= 0x00,
MT_LOCATE_BAM_EXPLICIT
= 0x01
} mt_locate_bam;
typedef enum {
MT_LOCATE_FLAG_IMMED
= 0x01,
MT_LOCATE_FLAG_CHANGE_PART
= 0x02
} mt_locate_flags;
struct mtlocate {
mt_locate_flags
flags;
mt_locate_dest_type
dest_type;
mt_locate_bam
block_address_mode;
int64_t
partition;
uint64_t
logical_id;
uint8_t
reserved[64];
};
typedef enum {
MT_EXT_GET_NONE,
MT_EXT_GET_OK,
MT_EXT_GET_NEED_MORE_SPACE,
MT_EXT_GET_ERROR
} mt_ext_get_status;
struct mtextget {
uint32_t
alloc_len;
char
*status_xml;
uint32_t
fill_len;
mt_ext_get_status
status;
char
error_str[128];
uint8_t
reserved[64];
};
#define
MT_EXT_GET_ROOT_NAME
"mtextget"
#define
MT_DENSITY_ROOT_NAME
"mtdensity"
#define
MT_MEDIA_DENSITY_NAME
"media_density"
#define
MT_DENSITY_REPORT_NAME
"density_report"
#define
MT_MEDIUM_TYPE_REPORT_NAME
"medium_type_report"
#define
MT_MEDIA_REPORT_NAME
"media_report"
#define
MT_DENSITY_ENTRY_NAME
"density_entry"
#define
MT_DENS_WRITE_OK
0x80
#define
MT_DENS_DUP
0x40
#define
MT_DENS_DEFLT
0x20
#define
MT_PARAM_FIXED_STR_LEN
32
union mt_param_value {
int64_t
value_signed;
uint64_t
value_unsigned;
char
*value_var_str;
char
value_fixed_str[MT_PARAM_FIXED_STR_LEN];
uint8_t
reserved[64];
};
typedef enum {
MT_PARAM_SET_NONE,
MT_PARAM_SET_SIGNED,
MT_PARAM_SET_UNSIGNED,
MT_PARAM_SET_VAR_STR,
MT_PARAM_SET_FIXED_STR
} mt_param_set_type;
typedef enum {
MT_PARAM_STATUS_NONE,
MT_PARAM_STATUS_OK,
MT_PARAM_STATUS_ERROR
} mt_param_set_status;
#define
MT_PARAM_VALUE_NAME_LEN
64
struct mtparamset {
char
value_name[MT_PARAM_VALUE_NAME_LEN];
mt_param_set_type
value_type;
int
value_len;
union mt_param_value
value;
mt_param_set_status
status;
char
error_str[128];
};
#define
MT_PARAM_ROOT_NAME
"mtparamget"
#define
MT_PROTECTION_NAME
"protection"
/*
* Set a list of parameters.
*/
struct mtsetlist {
int num_params;
int param_len;
struct mtparamset *params;
};
/*
* 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 */
#define MT_ISMFOUR
0x11
/* M4 Data 1/2 9track drive */
#define MT_ISTK50
0x12
/* DEC SCSI TK50 */
#define MT_ISMT02
0x13
/* Emulex MT02 SCSI tape controller */
/* 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 */
/* these two do not appear to be used anywhere */
#define MTIOCIEOT
_IO(’m’, 3)
/* ignore EOT error */
#define MTIOCEEOT
_IO(’m’, 4)
/* enable EOT error */
/*
* When more SCSI-3 SSC (streaming device) devices are out
there
* that support the full 32 byte type 2 structure,
we’ll have to
* rethink these ioctls to support all the entities they haul
into
* the picture (64 bit blocks, logical file record numbers,
etc..).
*/
#define
MTIOCRDSPOS
_IOR(’m’, 5, uint32_t)
/* get logical blk addr */
#define
MTIOCRDHPOS
_IOR(’m’, 6, uint32_t)
/* get hardware blk addr */
#define
MTIOCSLOCATE
_IOW(’m’, 5, uint32_t)
/* seek to logical blk addr */
#define
MTIOCHLOCATE
_IOW(’m’, 6, uint32_t)
/* seek to hardware blk addr */
#define
MTIOCERRSTAT
_IOR(’m’, 7, union mterrstat)
/* get tape errors */
/*
* Set EOT model- argument is number of filemarks to end a
tape with.
* Note that not all possible values will be accepted.
*/
#define
MTIOCSETEOTMODEL
_IOW(’m’, 8, uint32_t)
/* Get current EOT model */
#define
MTIOCGETEOTMODEL
_IOR(’m’, 8, uint32_t)
#define
MTIOCRBLIM
_IOR(’m’, 9, struct mtrblim) /* get block limits */
#define
MTIOCEXTLOCATE
_IOW(’m’, 10, struct mtlocate) /* seek to position */
#define
MTIOCEXTGET
_IOWR(’m’, 11, struct mtextget) /* get tape status */
#define
MTIOCPARAMGET
_IOWR(’m’, 12, struct mtextget) /* get tape params */
#define
MTIOCPARAMSET
_IOWR(’m’, 13, struct mtparamset) /* set tape params */
#define
MTIOCSETLIST
_IOWR(’m’, 14, struct mtsetlist) /* set N params */
#ifndef _KERNEL
#define
DEFTAPE
"/dev/nsa0"
#endif
#endif /* !_SYS_MTIO_H_ */
FILES
/dev/[en]sa*
SEE ALSO
HISTORY
The mtio manual appeared in 4.2BSD. An i386 version first appeared in FreeBSD 2.2.
BSD February 12, 2015 BSD