path: root/usr/src/man/man8/tapes.8

'\" te
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.TH TAPES 8 "Nov 8, 2002"
.SH NAME
tapes \- creates /dev entries for tape drives attached to the system
.SH SYNOPSIS
.LP
.nf
\fB/usr/sbin/tapes\fR [\fB-r\fR \fIroot_dir\fR]
.fi

.SH DESCRIPTION
.sp
.LP
\fBdevfsadm\fR(8) is now the preferred command for \fB/dev\fR and
\fB/devices\fR and should be used instead of \fBtapes\fR.
.sp
.LP
\fBtapes\fR creates symbolic links in the \fB/dev/rmt\fR directory to the
actual tape device special files under the \fB/devices\fR directory tree.
\fBtapes\fR searches the kernel device tree to see what tape devices are
attached to the system. For each equipped tape drive, the following steps are
performed:
.RS +4
.TP
1.
The \fB/dev/rmt\fR directory is searched for a \fB/dev/rmt/\fR\fIn\fR entry
that is a symbolic link to the \fB/devices\fR special node of the current tape
drive. If one is found, this determines the logical controller number of the
tape drive.
.RE
.RS +4
.TP
2.
The rest of the special devices associated with the drive are checked, and
incorrect symbolic links are removed and necessary ones added.
.RE
.RS +4
.TP
3.
If none are found, a new logical controller number is assigned (the
lowest-unused number), and new symbolic links are created for all the special
devices associated with the drive.
.RE
.sp
.LP
\fBtapes\fR does not remove links to non-existent devices; these must be
removed by hand.
.sp
.LP
\fBtapes\fR is run each time a reconfiguration-boot is performed, or when
\fBadd_drv\fR(8) is executed.
.SS "Notice to Driver Writers"
.sp
.LP
\fBtapes\fR(8) considers all devices with the node type \fBDDI_NT_TAPE\fR to
be tape devices; these devices must have their minor name created with a
specific format. The minor name encodes operational modes for the tape device
and consists of an \fBASCII\fR string of the form [
\fBl\fR,\fBm\fR,\fBh\fR,\fBc\fR,\fBu\fR ][ \fBb\fR ][ \fBn\fR ].
.sp
.LP
The first character set is used to specify the tape density of the device, and
are named low (\fBl\fR), medium (\fBm\fR), high (\fBh\fR), compressed
(\fBc\fR), and ultra (\fBu\fR). These specifiers only express a relative
density; it is up to the driver to assign specific meanings as needed. For
example, 9 track tape devices interpret these as actual bits-per-inch
densities, where \fBl\fR means 800 \fBBPI,\fR \fBm\fR means 1600 \fBBPI ,\fR
and \fBh\fR means 6250 \fBBPI,\fR whereas 4mm \fBDAT\fR tapes defines \fBl\fR
as standard format, and \fBm\fR, \fB h\fR, \fBc\fR and \fBu\fR as compressed
format. Drivers may choose to implement any or all of these format types.
.sp
.LP
During normal tape operation (non-\fBBSD\fR behavior), once an \fBEOF\fR mark
has been reached, subsequent reads from the tape device return an error. An
explicit IOCTL must be issued to space over the \fBEOF\fR mark before the next
file can be read. \fBb\fR instructs the device to observe \fBBSD\fR behavior,
where reading at \fBEOF\fR will cause the tape device to automatically space
over the \fBEOF\fR mark and begin reading from the next file.
.sp
.LP
\fBn\fR or no-rewind-on-close instructs the driver to not rewind to the
beginning of tape when the device is closed. Normal behavior for tape devices
is to reposition to BOT when closing. See \fBmtio\fR(4I).
.sp
.LP
The minor number for tape devices should be created by encoding the device's
instance number using the tape macro \fBMTMINOR\fR and ORing in the proper
combination of density, \fBBSD\fR behavior, and no-rewind flags. See
\fBmtio\fR(4I).
.sp
.LP
To prevent \fBtapes\fR from attempting to automatically generate links for a
device, drivers must specify a private node type and refrain from using the
node type string \fBDDI_NT_TAPE\fR when calling
\fBddi_create_minor_node\fR(9F).
.SH OPTIONS
.sp
.LP
The following options are supported:
.sp
.ne 2
.na
\fB\fB-r\fR \fIroot_dir\fR\fR
.ad
.RS 15n
Causes \fBtapes\fR to presume that the \fB/dev/rmt\fR directory tree is found
under \fIroot_dir\fR, not directly under \fB/\fR.
.RE

.SH ERRORS
.sp
.LP
If \fBtapes\fR finds entries of a particular logical controller linked to
different physical controllers, it prints an error message and exits without
making any changes to the \fB/dev\fR directory, since it cannot determine which
of the two alternative logical to physical mappings is correct. The links
should be manually corrected or removed before another reconfiguration boot is
performed.
.SH EXAMPLES
.LP
\fBExample 1 \fRCreating Tape Device Nodes From Within the Driver's
\fBattach()\fR Function
.sp
.LP
This example demonstrates creating tape device nodes from within the
\fBxktape\fR driver's \fBattach\fR(9E) function.

.sp
.in +2
.nf
#include <sys/mtio.h>
struct tape_minor_info {
    char *minor_name;
    int   minor_mode;
};
/*
 * create all combinations of logical tapes
*/
static struct tape_minor_info example_tape[] = {
   {"",    0},                     /* default tape */
   {"l",   MT_DENSITY1},
   {"lb",  MT_DENSITY1 | MT_BSD},
   {"lbn", MT_DENSITY1 | MT_BSD | MT_NOREWIND},
   {"m",   MT_DENSITY2},
   {"mb",  MT_DENSITY2 | MT_BSD},
   {"mbn", MT_DENSITY2 | MT_BSD | MT_NOREWIND},
   {"h",   MT_DENSITY3},
   {"hb",  MT_DENSITY3 | MT_BSD},
   {"hbn", MT_DENSITY3 | MT_BSD | MT_NOREWIND},
   {"c",   MT_DENSITY4},
   {"cb",  MT_DENSITY4 | MT_BSD},
   {"cbn", MT_DENSITY4| MT_BSD | MT_NOREWIND},
   {NULL,  0},
};

int
xktapeattach(dev_info_t *dip, ddi_attach_cmd_t cmd)
{
   int instance;
   struct tape_minor_info *mdp;
      /* other stuff in attach... */
   instance = ddi_get_instance(dip);

   for (mdp = example_tape; mdp->minor_name != NULL; mdp++) {
            ddi_create_minor_node(dip, mdp->minor_name, S_IFCHR,
                 (MTMINOR(instance) | mdp->minor_mode), DDI_NT_TAPE, 0);
 }
.fi
.in -2

.sp
.LP
Installing the \fBxktape\fR driver on a Sun Fire 4800, with the driver
controlling a \fBSCSI\fR tape (target 4 attached to an \fBisp\fR(4D) \fBSCSI
HBA)\fR and performing a reconfiguration-boot creates the following special
files in \fB/devices\fR.

.sp
.in +2
.nf
# ls -l /devices/ssm@0,0/pci@18,700000/pci@1/SUNW,isptwo@4
crw-rw-rw-   1 root sys   33,136 Aug 29 00:02  xktape@4,0:
crw-rw-rw-   1 root sys   33,200 Aug 29 00:02  xktape@4,0:b
crw-rw-rw-   1 root sys   33,204 Aug 29 00:02  xktape@4,0:bn
crw-rw-rw-   1 root sys   33,152 Aug 29 00:02  xktape@4,0:c
crw-rw-rw-   1 root sys   33,216 Aug 29 00:02  xktape@4,0:cb
crw-rw-rw-   1 root sys   33,220 Aug 29 00:02  xktape@4,0:cbn
crw-rw-rw-   1 root sys   33,156 Aug 29 00:02  xktape@4,0:cn
crw-rw-rw-   1 root sys   33,144 Aug 29 00:02  xktape@4,0:h
crw-rw-rw-   1 root sys   33,208 Aug 29 00:02  xktape@4,0:hb
crw-rw-rw-   1 root sys   33,212 Aug 29 00:02  xktape@4,0:hbn
crw-rw-rw-   1 root sys   33,148 Aug 29 00:02  xktape@4,0:hn
crw-rw-rw-   1 root sys   33,128 Aug 29 00:02  xktape@4,0:l
crw-rw-rw-   1 root sys   33,192 Aug 29 00:02  xktape@4,0:lb
crw-rw-rw-   1 root sys   33,196 Aug 29 00:02  xktape@4,0:lbn
crw-rw-rw-   1 root sys   33,132 Aug 29 00:02  xktape@4,0:ln
crw-rw-rw-   1 root sys   33,136 Aug 29 00:02  xktape@4,0:m
crw-rw-rw-   1 root sys   33,200 Aug 29 00:02  xktape@4,0:mb
crw-rw-rw-   1 root sys   33,204 Aug 29 00:02  xktape@4,0:mbn
crw-rw-rw-   1 root sys   33,140 Aug 29 00:02  xktape@4,0:mn
crw-rw-rw-   1 root sys   33,140 Aug 29 00:02  xktape@4,0:n
.fi
.in -2

.sp
.LP
\fB/dev/rmt\fR will contain the logical tape devices (symbolic links to tape
devices in \fB/devices\fR).

.sp
.in +2
.nf
# ls -l /dev/rmt
/dev/rmt/0    -> ../../devices/[....]/xktape@4,0:
/dev/rmt/0b   -> ../../devices/[....]/xktape@4,0:b
/dev/rmt/0bn  -> ../../devices/[....]/xktape@4,0:bn
/dev/rmt/0c   -> ../../devices/[....]/xktape@4,0:c
/dev/rmt/0cb  -> ../../devices/[....]/xktape@4,0:cb
/dev/rmt/0cbn -> ../../devices/[....]/xktape@4,0:cbn
/dev/rmt/0cn  -> ../../devices/[....]/xktape@4,0:cn
/dev/rmt/0h   -> ../../devices/[....]/xktape@4,0:h
/dev/rmt/0hb  -> ../../devices/[....]/xktape@4,0:hb
/dev/rmt/0hbn -> ../../devices/[....]/xktape@4,0:hbn
/dev/rmt/0hn  -> ../../devices/[....]/xktape@4,0:hn
/dev/rmt/0l   -> ../../devices/[....]/xktape@4,0:l
/dev/rmt/0lb  -> ../../devices/[....]/xktape@4,0:lb
/dev/rmt/0lbn -> ../../devices/[....]/xktape@4,0:lbn
/dev/rmt/0ln  -> ../../devices/[....]/xktape@4,0:ln
/dev/rmt/0m   -> ../../devices/[....]/xktape@4,0:m
/dev/rmt/0mb  -> ../../devices/[....]/xktape@4,0:mb
/dev/rmt/0mbn -> ../../devices/[....]/xktape@4,0:mbn
/dev/rmt/0mn  -> ../../devices/[....]/xktape@4,0:mn
/dev/rmt/0n   -> ../../devices/[....]/xktape@4,0:n
.fi
.in -2

.SH FILES
.sp
.ne 2
.na
\fB\fB/dev/rmt/*\fR\fR
.ad
.RS 14n
logical tape devices
.RE

.sp
.ne 2
.na
\fB\fB/devices/*\fR\fR
.ad
.RS 14n
tape device nodes
.RE

.SH SEE ALSO
.sp
.LP
.BR isp (4D),
.BR devfs (4FS),
.BR mtio (4I),
.BR attributes (7),
.BR add_drv (8),
.BR devfsadm (8),
.BR attach (9E),
.BR ddi_create_minor_node (9F)
.sp
.LP
\fI\fR
.SH BUGS
.sp
.LP
\fBtapes\fR silently ignores malformed minor device names.