disks(1M)
NAME
disks - creates /dev entries for hard disks attached to the
system
SYNOPSIS
/usr/sbin/disks [-C] [-r rootdir]
DESCRIPTION
devfsadm(1M) is now the preferred command for /dev and /dev-
ices and should be used instead of disks.
disks creates symbolic links in the /dev/dsk and /dev/rdsk
directories pointing to the actual disk device special files
under the /devices directory tree. It performs the follow-
ing steps:
1. disks searches the kernel device tree to see what hard
disks are attached to the system. It notes the /devices
pathnames for the slices on the drive and determines the
physical component of the corresponding /dev/dsk or
/dev/rdsk name.
2. The /dev/dsk and /dev/rdsk directories are checked for
disk entries - that is, symbolic links with names of the
form cN[tN]dNsN, or cN[tN]dNpN, where N represents a
decimal number. cN is the logical controller number, an
arbitrary number assigned by this program to designate a
particular disk controller. The first controller found on
the first occasion this program is run on a system, is
assigned number 0. tN is the bus-address number of a
subsidiary controller attached to a peripheral bus such
as SCSI or IPI (the target number for SCSI, and the
facility number for IPI controllers). dN is the number
of the disk attached to the controller. sN is the slice
number on the disk. pN is the FDISK partition number used
by fdisk(1M). (x86 Only)
3. If only some of the disk entries are found in /dev/dsk
for a disk that has been found under the /devices direc-
tory tree, disks creates the missing symbolic links. If
none of the entries for a particular disk are found in
/dev/dsk, disks checks to see if any entries exist for
other disks attached to the same controller, and if so,
creates new entries using the same controller number as
used for other disks on the same controller. If no other
/dev/dsk entries are found for slices of disks belonging
to the same physical controller as the current disk,
disks assigns the lowest-unused controller number and
creates entries for the disk slices using this newly-
assigned controller number.
disks is run automatically each time a reconfiguration-boot
is performed or when add_drv(1M) is executed. When invoking
disks(1M) manually, first run drvconfig(1M) to ensure /dev-
ices is consistent with the current device configuration.
Notice to Driver Writers
disks considers all devices with a node type of
DDI_NT_BLOCK, DDI_NT_BLOCK_CHAN, DDI_NT_CD, DDI_NT_BLOCK_WWN
or DDI_NT_CD_CHAN to be disk devices. disks(1M) requires
the minor name of disk devices obey the following format
conventions.
The minor name for block interfaces consists of a single
lowercase ASCII character, a through u. The minor name for
character (raw) interfaces consists of a single lowercase
ASCII character, a through u, followed by ,raw.
disks translates a through p to s0 through s15, while it
translates q through
u to p0 through p4. SPARC drivers should only use the
first 8 slices: a through h, while x86 drivers can use a
through u, with q through u corresponding to fdisk(1M)
partitions. q represents the entire disk, while r, s, t,
and u represent up to 4 additional partitions.
To prevent disks from attempting to automatically generate
links for a device, drivers must specify a private node
type and refrain from using a node type: DDI_NT_BLOCK,
DDI_NT_BLOCK_CHAN, DDI_NT_CD, or DDI_NT_CD_CHAN when cal-
ling ddi_create_minor_node(9F).
OPTIONS
-C Causes disks to remove any invalid links after adding
any new entries to /dev/dsk and /dev/rdsk. Invalid
links are links which refer to non-existent disk nodes
that have been removed, powered off, or are otherwise
inaccessible.
-r rootdir
Causes disks to presume that the /dev/dsk, /dev/rdsk
and /devices directory trees are found under rootdir,
not directly under /.
ERRORS
If disks 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 The Block And Character Minor Devices
From Within The xkdisk Driver's attach(9E) Function.
The following example demonstrates creating the block and
character minor devices from within the xkdisk driver's
attach(9E) function.
#include <sys/dkio.h>
/*
* Create the minor number by combining the instance number
* with the slice number.
*/
#define MINOR_NUM(i, s) ((i) << 4 | (s))
int
xkdiskattach(dev_info_t *dip, ddi_attach_cmd_t cmd)
{
int instance, slice;
char name[8];
/* other stuff in attach... */
instance = ddi_get_instance(dip);
for (slice = 0; slice < V_NUMPAR; slice++) {
/*
* create block device interface
*/
sprintf(name, "%c", slice + 'a');
ddi_create_minor_node(dip, name, S_IFBLK,
MINOR_NUM(instance, slice), DDI_NT_BLOCK_CHAN, 0);
/*
* create the raw (character) device interface
*/
sprintf(name,"%c,raw", slice + 'a');
ddi_create_minor_node(dip, name, S_IFCHR,
MINOR_NUM(instance, slice), DDI_NT_BLOCK_CHAN, 0);
}
}
Installing the xkdisk disk driver on a SPARCstation 20,
with the driver controlling a SCSI disk (target 3 attached
to an esp(7D) SCSI HBA) and performing a reconfiguration-
boot (causing disks to be run) creates the following special
files in /devices.
# ls -l /devices/iommu@f,e0000000/sbus@f,e0001000/espdma@f,400000/esp@f,800000/
brw-r----- 1 root sys 32, 16 Aug 29 00:02 xkdisk@3,0:a
crw-r----- 1 root sys 32, 16 Aug 29 00:02 xkdisk@3,0:a,raw
brw-r----- 1 root sys 32, 17 Aug 29 00:02 xkdisk@3,0:b
crw-r----- 1 root sys 32, 17 Aug 29 00:02 xkdisk@3,0:b,raw
brw-r----- 1 root sys 32, 18 Aug 29 00:02 xkdisk@3,0:c
crw-r----- 1 root sys 32, 18 Aug 29 00:02 xkdisk@3,0:c,raw
brw-r----- 1 root sys 32, 19 Aug 29 00:02 xkdisk@3,0:d
crw-r----- 1 root sys 32, 19 Aug 29 00:02 xkdisk@3,0:d,raw
brw-r----- 1 root sys 32, 20 Aug 29 00:02 xkdisk@3,0:e
crw-r----- 1 root sys 32, 20 Aug 29 00:02 xkdisk@3,0:e,raw
brw-r----- 1 root sys 32, 21 Aug 29 00:02 xkdisk@3,0:f
crw-r----- 1 root sys 32, 21 Aug 29 00:02 xkdisk@3,0:f,raw
brw-r----- 1 root sys 32, 22 Aug 29 00:02 xkdisk@3,0:g
crw-r----- 1 root sys 32, 22 Aug 29 00:02 xkdisk@3,0:g,raw
brw-r----- 1 root sys 32, 23 Aug 29 00:02 xkdisk@3,0:h
crw-r----- 1 root sys 32, 23 Aug 29 00:02 xkdisk@3,0:h,raw
/dev/dsk will contain the disk entries to the block device
nodes in /devices
# ls -l /dev/dsk
/dev/dsk/c0t3d0s0 -> ../../devices/[...]/xkdisk@3,0:a
/dev/dsk/c0t3d0s1 -> ../../devices/[...]/xkdisk@3,0:b
/dev/dsk/c0t3d0s2 -> ../../devices/[...]/xkdisk@3,0:c
/dev/dsk/c0t3d0s3 -> ../../devices/[...]/xkdisk@3,0:d
/dev/dsk/c0t3d0s4 -> ../../devices/[...]/xkdisk@3,0:e
/dev/dsk/c0t3d0s5 -> ../../devices/[...]/xkdisk@3,0:f
/dev/dsk/c0t3d0s6 -> ../../devices/[...]/xkdisk@3,0:g
/dev/dsk/c0t3d0s7 -> ../../devices/[...]/xkdisk@3,0:h
and /dev/rdsk will contain the disk entries for the charac-
ter device nodes in /devices
# ls -l /dev/rdsk
/dev/rdsk/c0t3d0s0 -> ../../devices/[...]/xkdisk@3,0:a,raw
/dev/rdsk/c0t3d0s1 -> ../../devices/[...]/xkdisk@3,0:b,raw
/dev/rdsk/c0t3d0s2 -> ../../devices/[...]/xkdisk@3,0:c,raw
/dev/rdsk/c0t3d0s3 -> ../../devices/[...]/xkdisk@3,0:d,raw
/dev/rdsk/c0t3d0s4 -> ../../devices/[...]/xkdisk@3,0:e,raw
/dev/rdsk/c0t3d0s5 -> ../../devices/[...]/xkdisk@3,0:f,raw
/dev/rdsk/c0t3d0s6 -> ../../devices/[...]/xkdisk@3,0:g,raw
/dev/rdsk/c0t3d0s7 -> ../../devices/[...]/xkdisk@3,0:h,raw
FILES
/dev/dsk/*
disk entries (block device interface)
/dev/rdsk/*
disk entries (character device interface)
/devices/*
device special files (minor 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), devlinks(1M), drvconfig(1M),
fdisk(1M), ports(1M), tapes(1M), attributes(5), dkio(7I),
esp(7D), attach(9E), ddi_create_minor_node(9F)
Writing Device Drivers
BUGS
disks silently ignores malformed minor device names.
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