mt.7 (2010 09)

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mt(7) mt(7)

NAME

mt - magnetic tape interface and controls for stape and estape

DESCRIPTION

This entry describes the behavior of HP magnetic tape interfaces and controls. The ﬁles

/dev/rtape/*

refer to speciﬁc raw tape drives controlled by the estape driver. The major number of these device special

ﬁles is dynamically allocated and the minor number does not encode any device speciﬁc information.

The ﬁles

/dev/rmt/* refer to speciﬁc raw tape drives controlled by the legacy stape driver, and the

behavior of each given unit is speciﬁed in the major and minor numbers of the DSF. The legacy driver

and DSFs are deprecated and will be removed in a future version of HP-UX.

Naming Conventions

The device special ﬁles (referred to as DSFs) for the

estape driver have the following naming conven-

tions:

/dev/rtape/tape#_BEST

[n][

There are four such ﬁles (referred to as persistent DSFs) corresponding to each of the four different per-

mutations of the

n and b options. These are claimed by the

estape driver. See intro (7) for more details

on persistent device special ﬁle names.

There are two naming conventions for legacy DSFs. The standard (preferred) convention is used on sys-

tems that support long ﬁle names. An alternate convention is provided for systems limited to short ﬁle

names. The following standard convention is recommended because it allows for all possible

conﬁguration options in the device name and is used by mksf (1M) and insf (1M):

/dev/rmt/c#t#d#[o][z][e][p][s

[#]][w]BEST[C[#]][n][b]

The following alternate naming convention is provided to support systems in which the

/dev/rmt direc-

tory requires short ﬁle names. These DSF names are less descriptive, but guarantee unique device nam-

ing and are used by mksf(1M) and insf (1M) where required.

/dev/rmt/c#t#d#[f#|i#][n][b

]

For each tape device present, twelve DSFs are automatically created when the system is installed. If

legacy mode is disabled (via the

-L option in rmsf), only four DSFs in

/dev/rtape will be created post

installation. These are claimed by the

estape driver.

Four legacy DSFs will be created in the

/dev/rmt directory using the following naming convention.

These are legacy DSFs and are claimed by the stape driver.

/dev/rmt/c#t#d#BEST[n][b].

Four more legacy DSFs with the format

/dev/rmt/#m

[n][b] will be automatically created when the sys-

tem is installed using the pre-HP-UX 10.0 device ﬁle naming convention. This includes an arbitrary

number to distinguish this tape device from others in the system, followed by the letter

m. There are four

such DSFs because each of the four different permutations of the

n and b options (see below) are created.

These ﬁles are created for compatability with pre-HP-UX 10.0 scripts and for users who ﬁnd the old con-

vention easier to remember.

Each of the automatically created DSFs which utilize the standard or alternate naming conventions is

linked to a device ﬁle which utilizes the pre-HP-UX 10.0 naming convention. That is, the DSFs in the for-

mat

/dev/rmt/#m[n][b] are created as hardlinks to the corresponding /dev/rmt/c#t#d#

BEST[n][b]

DSFs mentioned above.

Thus, the DSFs which utilize the pre-HP-UX 10.0 naming convention provide the same functionality as

the device ﬁles which contain the density speciﬁcation

BEST (standard naming convention).

Options

The options described here are common to all legacy tape drivers. The

c#t#d# notation in the legacy

DSF name derives from ioscan output and is described in the manpages for ioscan (1M) and intro (7).

c# Instance number assigned by the operating system to the interface card.

t# Target address on a remote bus (for example, SCSI address)

d# Device unit number at the target address (for example, SCSI LUN).

w Writes wait for physical completion of the operation before returning status. The default

behavior (buffered mode or immediate reporting mode) requires the tape device to buffer the

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (10 pages)

PAGE 1
mt(7) mt(7) NAME mt - magnetic tape interface and controls for stape and estape DESCRIPTION This entry describes the behavior of HP magnetic tape interfaces and controls. The files /dev/rtape/* refer to specific raw tape drives controlled by the estape driver. The major number of these device special files is dynamically allocated and the minor number does not encode any device specific information.
PAGE 2
mt(7) mt(7) data and return immediately with successful status. density A mA Density or format used in writing data to tape. This field is designated by the following values: BEST Highest-capacity density or format will be used, including data compression, if the device supports compression. NOMOD Maintains the density used for data previously written to the tape. Behavior using this option is dependent on the type of device. This option is only supported on DDS drives.
PAGE 3
mt(7) mt(7) When a file open for reading (only) is closed and the no-rewind bit is not set, the tape is rewound. If the no-rewind bit is set, the behaviour depends on the style mode. For AT&T-style devices, the tape is positioned after the EOF following the data just read (unless already at BOT or Filemark). For Berkeleystyle devices, the tape is not repositioned in any way. Each read (2) or write (2) call reads or writes the next record on the tape.
PAGE 4
mt(7) mt(7) mt_get_newdev_options() and mt_check_newdev_options() are utility functions used by the code snippets below.
PAGE 5
mt(7) mt(7) } dev = stbuf.st_rdev; io_init(O_RDWR); if(M_BERKELEY_AGILE(dev)) printf(" This is a Berkeley style device file "); else printf(" This is not a Berkeley style device file "); io_end(); exit(0); } Compile Line: cc -Ae -o test test.c -lIO Sample Output: # ./test /dev/rtape/tape1_BESTn This is not a Berkeley style device file # ./test /dev/rtape/tape1_BESTb This is a Berkeley style device file # ./test /dev/rmt/0mnb This is a Berkeley style device file # .
PAGE 6
mt(7) mt(7) (((dev) & (˜MT_INDEX_MASK)) | (index << MT_INDEX_BIT_POS) | MT_USER_CONFIG_MASK) : ((mt_check_newdev_options(dev, D_CHR, ˜MT_INDEX_MASK)) | (index << MT_INDEX_BIT_POS))) \ \ \ \ #define M_DFLT_DENSITY_PUT_AGILE(dev,density) ((io_is_legacy_dev(dev, D_CHR) == MT_IS_LEGACY_DEV) ? (((dev) & (˜MT_DENSITY_MASK)) | (density << MT_DENSITY_BIT_POS)) : ((mt_check_newdev_options(dev, D_CHR, ˜MT_DENSITY_MASK)) | (density << MT_DENSITY_BIT_POS))) \ \ \ \ \ #define M_TRANSPARENT_MODE_AGILE(dev) ((io_is_
PAGE 7
mt(7) mt(7) long long mt_dsreg1; mt_dsreg2; /* status register (msb) */ /* status register (lsb) */ /* The following are device-independent status words */ long long int32_t int32_t mt_gstat; mt_erreg; mt_fileno; mt_blkno; /* /* /* /* generic status error register No longer used No longer used */ */ - always set to -1 */ - always set to -1 */ Information for decoding the mt_type field can be found in . Tape operations work the same way for both legacy and agile devices.
PAGE 8
mt(7) A mA mt(7) GMT_D_DDS1(x ) Returns TRUE if the density encoded in mt_gstat is DDS1 (with or without compression). GMT_D_DDS1c(x ) Returns TRUE if the density encoded in mt_gstat is DDS1 plus compression. GMT_D_DDS2(x ) Returns TRUE if the density encoded in mt_gstat is DDS2 (with or without compression). GMT_D_DDS2c(x ) Returns TRUE if the density encoded in mt_gstat is DDS2 plus compression.
PAGE 9
mt(7) mt(7) #include #include struct mtop mtop; mtop.mt_op = MTFSS; mtop.mt_count = 1; ioctl(fd, MTIOCTOP, &mtop); Given that fd is a valid file descriptor for an opened tape device, and that it has just returned 0 from a read (2) request. The following system call verifies that the tape has just read a filemark: #include #include struct mtget mtget; ioctl(fd, MTIOCGET, &mtget); if (GMT_EOF (mtget.
PAGE 10
mt(7) mt(7) AUTHOR mt was developed by HP and the University of California, Berkeley. FILES /dev/rtape/* /dev/rmt/* /etc/mtconfig /dev/rmt/*config persistent tape DSFs claimed by the estape driver legacy tape DSFs constants and macros for use with tapes configuration property table for tapes device files for accessing configuration properties table - for internal use only SEE ALSO dd(1), mt(1), insf(1M), lssf(1M), mksf(1M), ioscan(1M), rmsf(1M), ioctl(2), lseek(2), libIO(3X), intro(7).