HP-UX Reference (11i v2 04/09) - 7 Device (Special) Files, 9 General Information, Index (vol 10)

m
mt(7) mt(7)
GMT_D_QIC_525(
x) Returns TRUE if the density encoded in mt_gstat is QIC-525
format.
GMT_D_QIC_1000(
x) Returns TRUE if the density encoded in mt_gstat
is QIC-
1000 format.
GMT_D_QIC_1350(
x) Returns TRUE if the density encoded in mt_gstat is QIC-
1350 format.
GMT_D_QIC_2100(
x) Returns TRUE if the density encoded in
mt_gstat is QIC-
2100 format.
GMT_D_QIC_2GB(
x) Returns TRUE if the density encoded in mt_gstat
is QIC-
2GB format.
GMT_D_QIC_5GB(
x) Returns TRUE if the density encoded in mt_gstat
is QIC-
5GB format.
GMT_D_8MM_8200(
x) Returns TRUE if the density encoded in
mt_gstat is 8 millim-
eter 8200 format (with or without compression).
GMT_D_8MM_8200c(
x) Returns TRUE if the density encoded in
mt_gstat is 8 millim-
eter 8200 format with compression.
GMT_D_8MM_8500(x)
Returns TRUE if the density encoded in mt_gstat is 8 millim-
eter 8500 format (with or without compression).
GMT_D_8MM_8500c(x
) Returns TRUE if the density encoded in mt_gstat is 8 millim-
eter 8500 format with compression.
GMT_MEDIUM(x) Identifies the 8-bit medium type value describing the tape
currently loaded into the tape device. The reported value is only
valid for QIC and 8mm devices. Supported values are defined in
<sys/mtio.h>.
GMT_QIC_MEDIUM(x
) Returns the same information as does GMT_MEDIUM(x).
GMT_MEDIUM(x) is preferred because GMT_QIC_MEDIUM
may
be obsoleted at some future date.
GMT_DR_OPEN(x) Does not apply to any currently supported devices. Always
returns FALSE.
HP-UX silently enforces a tape record blocking factor (
MAXPHYS) on large I/O requests. For example, a
user write request with a length of ten times MAXPHYS will actually reach the media as ten separate
records. A subsequent read (with ten times MAXPHYS as a length) will look like a single operation to the
user, even though HP-UX has broken it up into ten separate read requests to the driver. The blocking
function is transparent to the user during writes. It is also transparent during reads unless:
• The user picks an arbitrary read length greater than
MAXPHYS.
• The user attempts to read a third-party tape containing records larger than
MAXPHYS.
Since the value for
MAXPHYS is relatively large (usually >= 256K bytes), this is typically not a problem.
The
MTNOP operation does not set the device-independent status word.
3480 stacker devices are supported only in auto (that is, sequential-access) mode. To advance to the next
tape in the stack, an
MTIOCTOP control request specifying an MTOFFL operation should be issued. An
MTIOCGET control request should then be issued to determine whether or not the stacker has been suc-
cessfully advanced. Failure on the MTIOCGET operation (or an offline status) indicates that no more
tapes are available in the stacker, the stacker has been ejected, and user intervention is required to load
a new stack.
EXAMPLES
Assuming that fd is a valid file descriptor, the following example writes two consecutive filemarks on the
tape:
#include <sys/types.h>
#include <sys/mtio.h>
struct mtop mtop;
HP-UX 11i Version 2: September 2004 − 6 − Hewlett-Packard Company Section 7−−83