MTIO(4) BSD Kernel Interfaces Manual MTIO(4)
NAME
mtio — FreeBSD magtape interface
DESCRIPTION
The special files named /dev/[n]sa* refer to SCSI tape drives, which may be attached to the system. /dev/[n]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 usually prepended to the name of the no-rewind devices.
Tapes can be written with either fixed length records or variable length records. See sa(4) for more information. 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 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 */ |
|||
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 */ |
#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 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 */
short |
mt_resid; |
/* residual count */ |
#if defined (__FreeBSD__)
daddr_t mt_blksiz; |
/* presently operating blocksize */ |
|||
daddr_t mt_density; |
/* presently operating density */ |
|||
u_int32_t mt_comp; |
/* presently operating compression */ |
|||
daddr_t mt_blksiz0; |
/* blocksize for mode 0 */ |
|||
daddr_t mt_blksiz1; |
/* blocksize for mode 1 */ |
|||
daddr_t mt_blksiz2; |
/* blocksize for mode 2 */ |
|||
daddr_t mt_blksiz3; |
/* blocksize for mode 3 */ |
|||
daddr_t mt_density0; |
/* density for mode 0 */ |
|||
daddr_t mt_density1; |
/* density for mode 1 */ |
|||
daddr_t mt_density2; |
/* density for mode 2 */ |
|||
daddr_t mt_density3; |
/* density for mode 3 */ |
/* the following are not yet implemented */
u_int32_t mt_comp0; |
/* compression type for mode 0 */ |
|||
u_int32_t mt_comp1; |
/* compression type for mode 1 */ |
|||
u_int32_t mt_comp2; |
/* compression type for mode 2 */ |
|||
u_int32_t mt_comp3; |
/* compression type for mode 3 */ |
/* end not yet implemented */
#endif
daddr_t |
mt_fileno; |
/* relative file number of current position */ |
|||
daddr_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. |
||||||
*/ |
||||||
u_int8_t io_sense[32]; |
/* Last Sense Data For Data I/O */ |
|||||
u_int32_t io_resid; |
/* residual count from last Data I/O */ |
|||||
u_int8_t io_cdb[16]; |
/* Command that Caused the Last Data Sense */ |
|||||
u_int8_t ctl_sense[32]; |
/* Last Sense Data For Control I/O */ |
|||||
u_int32_t ctl_resid; |
/* residual count from last Control I/O */ |
|||||
u_int8_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 { |
||||||
u_int32_t retries; |
/* total # retries performed */ |
|||||
u_int32_t corrected; |
/* total # corrections performed */ |
|||||
u_int32_t processed; |
/* total # corrections successful */ |
|||||
u_int32_t failures; |
/* total # corrections/retries failed */ |
|||||
u_int64_t nbytes; |
/* total # bytes processed */ |
|||||
} wterr, rderr; |
};
union mterrstat {
struct scsi_tape_errors scsi_errstat; |
|
char _reserved_padding[256]; |
};
/*
* 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, u_int32_t) |
/* get logical blk addr */ |
|||||
#define |
MTIOCRDHPOS |
_IOR(’m’, 6, u_int32_t) |
/* get hardware blk addr */ |
|||||
#define |
MTIOCSLOCATE |
_IOW(’m’, 5, u_int32_t) |
/* seek to logical blk addr */ |
|||||
#define |
MTIOCHLOCATE |
_IOW(’m’, 6, u_int32_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, u_int32_t) |
/* Get current EOT model */
#define |
MTIOCGETEOTMODEL |
_IOR(’m’, 8, u_int32_t) |
#ifndef _KERNEL
#define |
DEFTAPE |
"/dev/nsa0" |
#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
#endif /* !_SYS_MTIO_H_ */
FILES
/dev/[n]sa*
SEE ALSO
HISTORY
The mtio manual appeared in 4.2BSD. An i386 version first appeared in FreeBSD 2.2.
BUGS
The status should be returned in a device independent format.
The special file naming should be redone in a more consistent and understandable manner.
BSD February 11, 1996 BSD