tapes(1M)
NAME
tapes - creates /dev entries for tape drives attached to the
system
SYNOPSIS
/usr/sbin/tapes [-r root_dir]
DESCRIPTION
devfsadm(1M) is now the preferred command for /dev and /dev-
ices and should be used instead of tapes.
tapes creates symbolic links in the /dev/rmt directory to
the actual tape device special files under the /devices
directory tree. tapes 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:
1. The /dev/rmt directory is searched for a /dev/rmt/n entry
that is a symbolic link to the /devices special node of
the current tape drive. If one is found, this determines
the logical controller number of the tape drive.
2. The rest of the special devices associated with the drive
are checked, and incorrect symbolic links are removed and
necessary ones added.
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.
tapes does not remove links to non-existent devices; these
must be removed by hand.
tapes is run each time a reconfiguration-boot is performed,
or when add_drv(1M) is executed.
Notice to Driver Writers
tapes(1M) considers all devices with the node type
DDI_NT_TAPE 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 con-
sists of an ASCII string of the form [ l,m,h,c,u ][ b ][ n
].
The first character set is used to specify the tape density
of the device, and are named low (l), medium (m), high (h),
compressed (c), and ultra (u). These specifiers only express
a relative density; it is up to the driver to assign
specific meanings as needed. For example, 9 track tape dev-
ices interpret these as actual bits-per-inch densities,
where l means 800 BPI, m means 1600 BPI , and h means 6250
BPI, whereas 4mm DAT tapes defines l as standard format, and
m, h, c and u as compressed format. Drivers may choose to
implement any or all of these format types.
During normal tape operation (non-BSD behavior), once an EOF
mark has been reached, subsequent reads from the tape device
return an error. An explicit IOCTL must be issued to space
over the EOF mark before the next file can be read. b
instructs the device to observe BSD behavior, where reading
at EOF will cause the tape device to automatically space
over the EOF mark and begin reading from the next file.
n 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 clos-
ing. See mtio(7I).
The minor number for tape devices should be created by
encoding the device's instance number using the tape macro
MTMINOR and ORing in the proper combination of density, BSD
behavior, and no-rewind flags. See mtio(7I).
To prevent tapes from attempting to automatically generate
links for a device, drivers must specify a private node type
and refrain from using the node type string DDI_NT_TAPE when
callingddi_create_minor_node(9F).
OPTIONS
The following options are supported:
-r root_dir
Causes tapes to presume that the /dev/rmt directory
tree is found under root_dir, not directly under /.
ERRORS
If tapes 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 /dev
directory, since it cannot determine which of the two alter-
native logical to physical mappings is correct. The links
should be manually corrected or removed before another
reconfiguration boot is performed.
EXAMPLES
Example 1: Creating Tape Device Nodes From Within the
Driver's attach() Function
This example demonstrates creating tape device nodes from
within the xktape driver's attach(9E) function.
#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);
}
Installing the xktape driver on a Sun Fire 4800, with the
driver controlling a SCSI tape (target 4 attached to an
isp(7D) SCSI HBA) and performing a reconfiguration-boot
creates the following special files in /devices.
# 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
/dev/rmt will contain the logical tape devices (symbolic
links to tape devices in /devices).
# 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
FILES
/dev/rmt/*
logical tape devices
/devices/*
tape device nodes
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
SEE ALSO
add_drv(1M), devfsadm(1M), attributes(5), isp(7D),
devfs(7FS), mtio(7I), attach(9E), ddi_create_minor_node(9F)
Writing Device Drivers
BUGS
tapes silently ignores malformed minor device names.
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