Use -mdoc properly.
Delete lots of out-of-date text. Write new text to replace some of the old text. BDE will need to inspect the results for accuracy.
This commit is contained in:
Garrett Wollman
parent
feff7a1342
commit
35fe659d58
@ -1,221 +1,247 @@
|
||||
.Dd August 27, 1993
|
||||
.Dd January 18, 1996
|
||||
.Dt SD 4
|
||||
.Os FreeBSD
|
||||
.Sh NAME
|
||||
.Nm sd
|
||||
.Nd scsi disk driver
|
||||
.Nd SCSI disk driver
|
||||
.Sh SYNOPSIS
|
||||
.Nm disk sd
|
||||
.Nm disk sd1 target 4 lun 0
|
||||
.Cd disk sd
|
||||
.Cd disk sd1 at scbus0 target 4 lun 0
|
||||
.Sh DESCRIPTION
|
||||
The
|
||||
.Xr sd
|
||||
.Nm sd
|
||||
driver provides support for a
|
||||
.Em scsi
|
||||
.Tn SCSI
|
||||
disk. It allows the disk
|
||||
to be divided up into a set of pseudo devices called
|
||||
.Em partitions.
|
||||
A Partition can have both a
|
||||
.Em raw
|
||||
interface
|
||||
and a
|
||||
.Em Block mode
|
||||
interface.
|
||||
.Em partitions .
|
||||
In general the interfaces are similar to those described by
|
||||
.Xr wd 4
|
||||
or
|
||||
.Xr dk 4 .
|
||||
|
||||
.Xr wd 4 .
|
||||
.Pp
|
||||
Where the
|
||||
.Xr wd 4
|
||||
device has a fairly low level interface to the system,
|
||||
.Em SCSI
|
||||
.Tn SCSI
|
||||
devices have a much higher level interface and talk to the system via
|
||||
a
|
||||
.Em SCSI Adapter
|
||||
and a
|
||||
.Em Scsi Adapter driver
|
||||
e.g.
|
||||
.Xr AHA1542 .
|
||||
A scsi adapter must also be separatly configured into the system
|
||||
before a scsi disk can be configured.
|
||||
.Tn SCSI
|
||||
host adapter
|
||||
(e.g.,
|
||||
.Xr ahc 4 ) .
|
||||
A
|
||||
.Tn SCSI
|
||||
adapter must also be separately configured into the system
|
||||
before a
|
||||
.Tn SCSI
|
||||
disk can be configured.
|
||||
.Pp
|
||||
As the scsi adapter is probed during boot, the
|
||||
.Em SCSI
|
||||
bus is scanned for devices. Any devices found which answer as 'Direct'
|
||||
type devices will be 'attached' to the
|
||||
When the
|
||||
.Tn SCSI
|
||||
adapter is probed during boot, the
|
||||
.Tn SCSI
|
||||
bus is scanned for devices. Any devices found which answer as
|
||||
.Sq Em Direct
|
||||
type devices will be attached to the
|
||||
.Nm
|
||||
driver.
|
||||
In FreeBSD releases prior to 2.1, the first found will be attached as
|
||||
.Em sd0
|
||||
and the next,
|
||||
.Em sd1
|
||||
etc.
|
||||
Beginning in 2.1 it is possible to specify what sd unit a device should
|
||||
come on line as; refer to
|
||||
In
|
||||
.Tn FreeBSD
|
||||
releases prior to 2.1, the first found was attached as
|
||||
.Li sd0 ,
|
||||
the second
|
||||
.Li sd1 ,
|
||||
and so on.
|
||||
Beginning in 2.1 it became possible to lock down the assignment of
|
||||
devices on the
|
||||
.Tn SCSI
|
||||
bus to particular units of the
|
||||
.Nm
|
||||
decice; refer to
|
||||
.Xr scsi 4
|
||||
for details on kernel configuration.
|
||||
.Pp
|
||||
.Sh PARTITIONING
|
||||
The
|
||||
.Nm
|
||||
driver allows the disk to have two levels of partitioning.
|
||||
One which allows it to have
|
||||
partitions for different Operating systems, (one of which is BSD unix),
|
||||
(see also for the 386 port,
|
||||
.Xr fdisk 1
|
||||
), and within a BSD partition, further partitions which are individually
|
||||
addressable as separate entries in the
|
||||
.Em /dev
|
||||
directory. The second level of partitioning is controlled by the program
|
||||
.Xr disklabel 1
|
||||
and is common in format across most BSD operating systems. In most of
|
||||
the original BSD ports, what is the
|
||||
BSD part here, is the entire disk, and the outer layer of partitionning
|
||||
does not exist.
|
||||
.Nm
|
||||
will also run in this manner if
|
||||
.Xr disklabel 1
|
||||
is run with a blank disk, without first partitioning it
|
||||
with
|
||||
.Xr fdisk 1
|
||||
(or similar).
|
||||
|
||||
.Pp
|
||||
Apologies for the two conflicting usages of the word Partition, but
|
||||
it's a historical artifact, and the meaning must be judged from context
|
||||
in each case. The next paragraph will discuss partitions exclusively
|
||||
in the context of WITHIN a BSD partition on the disk.
|
||||
.Pp
|
||||
The first few blocks of the BSD section (maybe all) of the disk contain
|
||||
some boot code, and a structure, known as the
|
||||
.Xr disklabel 5
|
||||
which describes the disk's characteristics and partitioning for BSD.
|
||||
It is set up by the
|
||||
.Xr disklabel 1
|
||||
program, and read in by the kernel when the device is first initialised
|
||||
during boot. It describes how the drive is further divided. The
|
||||
.Xr disklabel 5
|
||||
structure contains room for 8 (usually) partitions. Usually these
|
||||
partitions are calculated so as to fall evenly on cylinder boundaries,
|
||||
however on a
|
||||
.Em SCSI
|
||||
disk this is sometimes not possible. The reason for doing this is historically
|
||||
to get better performance, however modern
|
||||
.Em SCSI
|
||||
disks often have a variable format, so that it is hard to know at any point
|
||||
in the disk, where the cylinder or track boundaries are. Added to this, the
|
||||
fact that
|
||||
.Em SCSI
|
||||
disk blocks are addressed soley by their 'block number' and not by
|
||||
any geometry, leads to the common occurance on
|
||||
.Em SCSI
|
||||
disks, of laying out partitions on arbitrary boundaries. Because
|
||||
modern disks often have large track caches, this often leads to only small
|
||||
degadations of performance, and is in fact sometimes unavoidable. The
|
||||
boot messages will suggest a geometry similar in heads and cylinders
|
||||
to the real geometry, but the disklable need not agree with this for the
|
||||
system to be able to successfully work with the disk.
|
||||
.Pp
|
||||
During booting
|
||||
with an uninitialised disk, the
|
||||
.Nm
|
||||
driver will initialise the 'in-core' copy of the disklabel to the suggested
|
||||
values, however they are not written to the disk.
|
||||
.Pp
|
||||
The fourth partition is special. No matter what the disklabel
|
||||
says, the fourth partition (partition d) reflectls the entire disk, including
|
||||
those areas OUTSIDE the BSD partitions. At some times it is suggested that
|
||||
the c partition might be used to represent the entire BSD partition, so these
|
||||
two partitions should be avoided when laying out filesystems. The fourth
|
||||
partition must be used for general
|
||||
.Xr scsi 4
|
||||
ioctls.
|
||||
.Pp
|
||||
While partitions are only theoretically valid within the BSD partition, they
|
||||
are specified in terms of absolute block numbers, so it is possible to
|
||||
specify a partition that lies outside of the BSD partition. This is useful
|
||||
if one wants to have a /dev entry that points to a partition belonging
|
||||
to another OS (e.g. DOS).
|
||||
One layer, called the
|
||||
.Dq slice layer ,
|
||||
is used to separate the
|
||||
.Tn FreeBSD
|
||||
areas of the disk from areas used by other operating systems.
|
||||
The second layer is the native
|
||||
.Bx 4.4
|
||||
partitioning scheme,
|
||||
.Xr disklabel 5 ,
|
||||
which is used to subdivide the
|
||||
.Tn FreeBSD
|
||||
slices into areas for individual filesystems and swap spaces.
|
||||
For more information, see
|
||||
.Xr fdisk 8
|
||||
and
|
||||
.Xr disklabel 8 ,
|
||||
respectively.)
|
||||
.Pp
|
||||
If an uninitialized disk is opened, the slice table will be
|
||||
initialized with a fictitious
|
||||
.Tn FreeBSD
|
||||
slice spanning the entire disk. Similarly, if an uninitialized
|
||||
(or
|
||||
.No non- Ns Tn FreeBSD )
|
||||
slice is opened, its disklabel will be initialized with parameters returned
|
||||
by the drive and a single
|
||||
.Sq Li c
|
||||
partition encompassing the entire slice.
|
||||
.Sh KERNEL CONFIGURATION
|
||||
In configuring, if an optional
|
||||
.Ar count
|
||||
is given in
|
||||
the specification, that number of scsi disks are configured;
|
||||
Most storage for them is allocated only when found so a large number
|
||||
of configured devices is cheap. (once the first has included the driver).
|
||||
|
||||
.Pp
|
||||
It is only necessary to explicitly configure one
|
||||
.Nm
|
||||
device; data structures are dynamically allocated as disks are found
|
||||
on the
|
||||
.Tn SCSI
|
||||
bus.
|
||||
.Sh IOCTLS
|
||||
The following
|
||||
.Xr ioctl 2
|
||||
calls apply to scsi disks as well as to other disks. They are defined
|
||||
in the header file
|
||||
.Em disklabel.h.
|
||||
|
||||
calls apply to
|
||||
.Tn SCSI
|
||||
disks as well as to other disks. They are defined in the header file
|
||||
.Aq Pa disklabel.h .
|
||||
.Pp
|
||||
.Bl -tag -width DIOCSDINFO
|
||||
|
||||
.It Dv DIOCSBAD
|
||||
Usually used to set up a bad-block mapping system on the disk. Scsi
|
||||
drive incorporate their own bad-block mapping so this is not implimented,
|
||||
however it MAY be implimented in the future as a 'kludged' interface to the
|
||||
scsi bad-block mapping.
|
||||
Usually used to set up a bad-block mapping system on the disk.
|
||||
.Tn SCSI
|
||||
drive incorporate their own bad-block mapping so this command is not
|
||||
implimented.
|
||||
.It Dv DIOCGDINFO
|
||||
Read, from the kernel, the in-core copy of the disklabel for the
|
||||
drive. This may be a ficticious disklabel if the drive has never
|
||||
been initialised, in which case it will contain information read
|
||||
from the scsi inquiry commands, and should be the same as
|
||||
the information printed at boot.
|
||||
from the
|
||||
.Tn SCSI
|
||||
inquiry commands.
|
||||
.It Dv DIOCSDINFO
|
||||
Give the driver a new disklabel to use. The driver will NOT try write the new
|
||||
Give the driver a new disklabel to use. The driver
|
||||
.Em will not
|
||||
write the new
|
||||
disklabel to the disk.
|
||||
.It Dv DIOCWLABEL
|
||||
Enable or Disable the driver's software
|
||||
Enable or disable the driver's software
|
||||
write protect of the disklabel on the disk.
|
||||
.It Dv DIOCWDINFO
|
||||
Give the driver a new disklabel to use. The driver WILL try write the new
|
||||
disklabel to the disk.
|
||||
Give the driver a new disklabel to use. The driver
|
||||
.Em will
|
||||
write the new disklabel to the disk.
|
||||
.El
|
||||
.Pp
|
||||
In addition, the
|
||||
.Xr scsi 4
|
||||
general ioctls may be used with the
|
||||
general
|
||||
.Fn ioctl
|
||||
commands may be used with the
|
||||
.Nm
|
||||
driver, but only against the fourth (whole disk) partition.
|
||||
driver, but only against the
|
||||
.Sq Li c
|
||||
(whole disk) partition.
|
||||
.Sh NOTES
|
||||
If a removable device is attached to the
|
||||
.Nm
|
||||
driver, then the act of changing the media will invalidate the
|
||||
disklabel and information held within the kernel. To stop corruption,
|
||||
All accesses to the device will be discarded until there are no more
|
||||
open file descriptors referencing the device. During this period, all
|
||||
new open attempts will be rejected. When No more open file descriptors
|
||||
reference the device, the first next open will load a new set of
|
||||
figures (including disklabel) for the drive.
|
||||
|
||||
An ioctl to map out a bad block is planned. (the code is already present
|
||||
in the driver).
|
||||
|
||||
driver, then the act of changing the media will invalidate the
|
||||
disklabel and information held within the kernel. To avoid
|
||||
corruption, all accesses to the device will be discarded until there
|
||||
are no more open file descriptors referencing the device. During this
|
||||
period, all new open attempts will be rejected. When no more open
|
||||
file descriptors reference the device, the first next open will load a
|
||||
new set of parameters (including disklabel) for the drive.
|
||||
.Sh FILES
|
||||
.Bl -tag -width /dev/rsd[0-9][a-h] -compact
|
||||
.It Pa /dev/sd[0-9][a-h]
|
||||
block mode scsi disks
|
||||
.It Pa /dev/rsd[0-9][a-h]
|
||||
raw scsi disks
|
||||
.Bl -tag -width /dev/rsdXXXXX -compact
|
||||
.It Pa /dev/rsd Ns Ar u
|
||||
raw mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
accessed as an unpartitioned device
|
||||
.Sm off
|
||||
.It Pa /dev/sd Ar u Pa s Ar n
|
||||
.Sm on
|
||||
block mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
slice
|
||||
.Ar n ,
|
||||
accessed as an unpartitioned device
|
||||
.Sm off
|
||||
.It Pa /dev/rsd Ar u Pa s Ar n
|
||||
.Sm on
|
||||
raw mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
slice
|
||||
.ar n ,
|
||||
accessed as an unpartitioned device
|
||||
.It Pa /dev/sd Ns Ar u Ns Ar p
|
||||
block mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
first
|
||||
.Tn FreeBSD
|
||||
slice, partition
|
||||
.Ar p
|
||||
.It Pa /dev/rsd Ns Ar u Ns Ar p
|
||||
raw mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
first
|
||||
.Tn FreeBSD
|
||||
slice, partition
|
||||
.Ar p
|
||||
.Sm off
|
||||
.It Xo
|
||||
.Pa /dev/sd
|
||||
.Ar u
|
||||
.Pa s
|
||||
.Ar n
|
||||
.Ar p
|
||||
.Xc
|
||||
.Sm on
|
||||
block mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
.No Ar n Ns th
|
||||
slice, partition
|
||||
.Ar p
|
||||
.Sm off
|
||||
.It Xo
|
||||
.Pa /dev/rsd
|
||||
.Ar u
|
||||
.Pa s
|
||||
.Ar n
|
||||
.Ar p
|
||||
.Xc
|
||||
raw mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
.No Ar n Ns th
|
||||
slice, partition
|
||||
.Ar p
|
||||
.El
|
||||
.Sh DIAGNOSTICS
|
||||
None.
|
||||
.Sh SEE ALSO
|
||||
.Xr disklabel 1
|
||||
.Xr disklabel 8 ,
|
||||
.Xr fdisk 8 ,
|
||||
.Xr wd 4 ,
|
||||
.Xr disklabel 5
|
||||
.Xr fdisk 1
|
||||
.Xr wd 4
|
||||
.Xr dk 4
|
||||
(on other systems)
|
||||
.Sh HISTORY
|
||||
The
|
||||
.Nm
|
||||
driver appeared in MACH 2.5 .
|
||||
|
||||
driver was originally written for
|
||||
.Tn Mach
|
||||
2.5, and was ported to
|
||||
.Tn FreeBSD
|
||||
by Julian Elischer. Support for slices was written by Bruce Evans.
|
||||
|
||||
@ -1,221 +1,247 @@
|
||||
.Dd August 27, 1993
|
||||
.Dd January 18, 1996
|
||||
.Dt SD 4
|
||||
.Os FreeBSD
|
||||
.Sh NAME
|
||||
.Nm sd
|
||||
.Nd scsi disk driver
|
||||
.Nd SCSI disk driver
|
||||
.Sh SYNOPSIS
|
||||
.Nm disk sd
|
||||
.Nm disk sd1 target 4 lun 0
|
||||
.Cd disk sd
|
||||
.Cd disk sd1 at scbus0 target 4 lun 0
|
||||
.Sh DESCRIPTION
|
||||
The
|
||||
.Xr sd
|
||||
.Nm sd
|
||||
driver provides support for a
|
||||
.Em scsi
|
||||
.Tn SCSI
|
||||
disk. It allows the disk
|
||||
to be divided up into a set of pseudo devices called
|
||||
.Em partitions.
|
||||
A Partition can have both a
|
||||
.Em raw
|
||||
interface
|
||||
and a
|
||||
.Em Block mode
|
||||
interface.
|
||||
.Em partitions .
|
||||
In general the interfaces are similar to those described by
|
||||
.Xr wd 4
|
||||
or
|
||||
.Xr dk 4 .
|
||||
|
||||
.Xr wd 4 .
|
||||
.Pp
|
||||
Where the
|
||||
.Xr wd 4
|
||||
device has a fairly low level interface to the system,
|
||||
.Em SCSI
|
||||
.Tn SCSI
|
||||
devices have a much higher level interface and talk to the system via
|
||||
a
|
||||
.Em SCSI Adapter
|
||||
and a
|
||||
.Em Scsi Adapter driver
|
||||
e.g.
|
||||
.Xr AHA1542 .
|
||||
A scsi adapter must also be separatly configured into the system
|
||||
before a scsi disk can be configured.
|
||||
.Tn SCSI
|
||||
host adapter
|
||||
(e.g.,
|
||||
.Xr ahc 4 ) .
|
||||
A
|
||||
.Tn SCSI
|
||||
adapter must also be separately configured into the system
|
||||
before a
|
||||
.Tn SCSI
|
||||
disk can be configured.
|
||||
.Pp
|
||||
As the scsi adapter is probed during boot, the
|
||||
.Em SCSI
|
||||
bus is scanned for devices. Any devices found which answer as 'Direct'
|
||||
type devices will be 'attached' to the
|
||||
When the
|
||||
.Tn SCSI
|
||||
adapter is probed during boot, the
|
||||
.Tn SCSI
|
||||
bus is scanned for devices. Any devices found which answer as
|
||||
.Sq Em Direct
|
||||
type devices will be attached to the
|
||||
.Nm
|
||||
driver.
|
||||
In FreeBSD releases prior to 2.1, the first found will be attached as
|
||||
.Em sd0
|
||||
and the next,
|
||||
.Em sd1
|
||||
etc.
|
||||
Beginning in 2.1 it is possible to specify what sd unit a device should
|
||||
come on line as; refer to
|
||||
In
|
||||
.Tn FreeBSD
|
||||
releases prior to 2.1, the first found was attached as
|
||||
.Li sd0 ,
|
||||
the second
|
||||
.Li sd1 ,
|
||||
and so on.
|
||||
Beginning in 2.1 it became possible to lock down the assignment of
|
||||
devices on the
|
||||
.Tn SCSI
|
||||
bus to particular units of the
|
||||
.Nm
|
||||
decice; refer to
|
||||
.Xr scsi 4
|
||||
for details on kernel configuration.
|
||||
.Pp
|
||||
.Sh PARTITIONING
|
||||
The
|
||||
.Nm
|
||||
driver allows the disk to have two levels of partitioning.
|
||||
One which allows it to have
|
||||
partitions for different Operating systems, (one of which is BSD unix),
|
||||
(see also for the 386 port,
|
||||
.Xr fdisk 1
|
||||
), and within a BSD partition, further partitions which are individually
|
||||
addressable as separate entries in the
|
||||
.Em /dev
|
||||
directory. The second level of partitioning is controlled by the program
|
||||
.Xr disklabel 1
|
||||
and is common in format across most BSD operating systems. In most of
|
||||
the original BSD ports, what is the
|
||||
BSD part here, is the entire disk, and the outer layer of partitionning
|
||||
does not exist.
|
||||
.Nm
|
||||
will also run in this manner if
|
||||
.Xr disklabel 1
|
||||
is run with a blank disk, without first partitioning it
|
||||
with
|
||||
.Xr fdisk 1
|
||||
(or similar).
|
||||
|
||||
.Pp
|
||||
Apologies for the two conflicting usages of the word Partition, but
|
||||
it's a historical artifact, and the meaning must be judged from context
|
||||
in each case. The next paragraph will discuss partitions exclusively
|
||||
in the context of WITHIN a BSD partition on the disk.
|
||||
.Pp
|
||||
The first few blocks of the BSD section (maybe all) of the disk contain
|
||||
some boot code, and a structure, known as the
|
||||
.Xr disklabel 5
|
||||
which describes the disk's characteristics and partitioning for BSD.
|
||||
It is set up by the
|
||||
.Xr disklabel 1
|
||||
program, and read in by the kernel when the device is first initialised
|
||||
during boot. It describes how the drive is further divided. The
|
||||
.Xr disklabel 5
|
||||
structure contains room for 8 (usually) partitions. Usually these
|
||||
partitions are calculated so as to fall evenly on cylinder boundaries,
|
||||
however on a
|
||||
.Em SCSI
|
||||
disk this is sometimes not possible. The reason for doing this is historically
|
||||
to get better performance, however modern
|
||||
.Em SCSI
|
||||
disks often have a variable format, so that it is hard to know at any point
|
||||
in the disk, where the cylinder or track boundaries are. Added to this, the
|
||||
fact that
|
||||
.Em SCSI
|
||||
disk blocks are addressed soley by their 'block number' and not by
|
||||
any geometry, leads to the common occurance on
|
||||
.Em SCSI
|
||||
disks, of laying out partitions on arbitrary boundaries. Because
|
||||
modern disks often have large track caches, this often leads to only small
|
||||
degadations of performance, and is in fact sometimes unavoidable. The
|
||||
boot messages will suggest a geometry similar in heads and cylinders
|
||||
to the real geometry, but the disklable need not agree with this for the
|
||||
system to be able to successfully work with the disk.
|
||||
.Pp
|
||||
During booting
|
||||
with an uninitialised disk, the
|
||||
.Nm
|
||||
driver will initialise the 'in-core' copy of the disklabel to the suggested
|
||||
values, however they are not written to the disk.
|
||||
.Pp
|
||||
The fourth partition is special. No matter what the disklabel
|
||||
says, the fourth partition (partition d) reflectls the entire disk, including
|
||||
those areas OUTSIDE the BSD partitions. At some times it is suggested that
|
||||
the c partition might be used to represent the entire BSD partition, so these
|
||||
two partitions should be avoided when laying out filesystems. The fourth
|
||||
partition must be used for general
|
||||
.Xr scsi 4
|
||||
ioctls.
|
||||
.Pp
|
||||
While partitions are only theoretically valid within the BSD partition, they
|
||||
are specified in terms of absolute block numbers, so it is possible to
|
||||
specify a partition that lies outside of the BSD partition. This is useful
|
||||
if one wants to have a /dev entry that points to a partition belonging
|
||||
to another OS (e.g. DOS).
|
||||
One layer, called the
|
||||
.Dq slice layer ,
|
||||
is used to separate the
|
||||
.Tn FreeBSD
|
||||
areas of the disk from areas used by other operating systems.
|
||||
The second layer is the native
|
||||
.Bx 4.4
|
||||
partitioning scheme,
|
||||
.Xr disklabel 5 ,
|
||||
which is used to subdivide the
|
||||
.Tn FreeBSD
|
||||
slices into areas for individual filesystems and swap spaces.
|
||||
For more information, see
|
||||
.Xr fdisk 8
|
||||
and
|
||||
.Xr disklabel 8 ,
|
||||
respectively.)
|
||||
.Pp
|
||||
If an uninitialized disk is opened, the slice table will be
|
||||
initialized with a fictitious
|
||||
.Tn FreeBSD
|
||||
slice spanning the entire disk. Similarly, if an uninitialized
|
||||
(or
|
||||
.No non- Ns Tn FreeBSD )
|
||||
slice is opened, its disklabel will be initialized with parameters returned
|
||||
by the drive and a single
|
||||
.Sq Li c
|
||||
partition encompassing the entire slice.
|
||||
.Sh KERNEL CONFIGURATION
|
||||
In configuring, if an optional
|
||||
.Ar count
|
||||
is given in
|
||||
the specification, that number of scsi disks are configured;
|
||||
Most storage for them is allocated only when found so a large number
|
||||
of configured devices is cheap. (once the first has included the driver).
|
||||
|
||||
.Pp
|
||||
It is only necessary to explicitly configure one
|
||||
.Nm
|
||||
device; data structures are dynamically allocated as disks are found
|
||||
on the
|
||||
.Tn SCSI
|
||||
bus.
|
||||
.Sh IOCTLS
|
||||
The following
|
||||
.Xr ioctl 2
|
||||
calls apply to scsi disks as well as to other disks. They are defined
|
||||
in the header file
|
||||
.Em disklabel.h.
|
||||
|
||||
calls apply to
|
||||
.Tn SCSI
|
||||
disks as well as to other disks. They are defined in the header file
|
||||
.Aq Pa disklabel.h .
|
||||
.Pp
|
||||
.Bl -tag -width DIOCSDINFO
|
||||
|
||||
.It Dv DIOCSBAD
|
||||
Usually used to set up a bad-block mapping system on the disk. Scsi
|
||||
drive incorporate their own bad-block mapping so this is not implimented,
|
||||
however it MAY be implimented in the future as a 'kludged' interface to the
|
||||
scsi bad-block mapping.
|
||||
Usually used to set up a bad-block mapping system on the disk.
|
||||
.Tn SCSI
|
||||
drive incorporate their own bad-block mapping so this command is not
|
||||
implimented.
|
||||
.It Dv DIOCGDINFO
|
||||
Read, from the kernel, the in-core copy of the disklabel for the
|
||||
drive. This may be a ficticious disklabel if the drive has never
|
||||
been initialised, in which case it will contain information read
|
||||
from the scsi inquiry commands, and should be the same as
|
||||
the information printed at boot.
|
||||
from the
|
||||
.Tn SCSI
|
||||
inquiry commands.
|
||||
.It Dv DIOCSDINFO
|
||||
Give the driver a new disklabel to use. The driver will NOT try write the new
|
||||
Give the driver a new disklabel to use. The driver
|
||||
.Em will not
|
||||
write the new
|
||||
disklabel to the disk.
|
||||
.It Dv DIOCWLABEL
|
||||
Enable or Disable the driver's software
|
||||
Enable or disable the driver's software
|
||||
write protect of the disklabel on the disk.
|
||||
.It Dv DIOCWDINFO
|
||||
Give the driver a new disklabel to use. The driver WILL try write the new
|
||||
disklabel to the disk.
|
||||
Give the driver a new disklabel to use. The driver
|
||||
.Em will
|
||||
write the new disklabel to the disk.
|
||||
.El
|
||||
.Pp
|
||||
In addition, the
|
||||
.Xr scsi 4
|
||||
general ioctls may be used with the
|
||||
general
|
||||
.Fn ioctl
|
||||
commands may be used with the
|
||||
.Nm
|
||||
driver, but only against the fourth (whole disk) partition.
|
||||
driver, but only against the
|
||||
.Sq Li c
|
||||
(whole disk) partition.
|
||||
.Sh NOTES
|
||||
If a removable device is attached to the
|
||||
.Nm
|
||||
driver, then the act of changing the media will invalidate the
|
||||
disklabel and information held within the kernel. To stop corruption,
|
||||
All accesses to the device will be discarded until there are no more
|
||||
open file descriptors referencing the device. During this period, all
|
||||
new open attempts will be rejected. When No more open file descriptors
|
||||
reference the device, the first next open will load a new set of
|
||||
figures (including disklabel) for the drive.
|
||||
|
||||
An ioctl to map out a bad block is planned. (the code is already present
|
||||
in the driver).
|
||||
|
||||
driver, then the act of changing the media will invalidate the
|
||||
disklabel and information held within the kernel. To avoid
|
||||
corruption, all accesses to the device will be discarded until there
|
||||
are no more open file descriptors referencing the device. During this
|
||||
period, all new open attempts will be rejected. When no more open
|
||||
file descriptors reference the device, the first next open will load a
|
||||
new set of parameters (including disklabel) for the drive.
|
||||
.Sh FILES
|
||||
.Bl -tag -width /dev/rsd[0-9][a-h] -compact
|
||||
.It Pa /dev/sd[0-9][a-h]
|
||||
block mode scsi disks
|
||||
.It Pa /dev/rsd[0-9][a-h]
|
||||
raw scsi disks
|
||||
.Bl -tag -width /dev/rsdXXXXX -compact
|
||||
.It Pa /dev/rsd Ns Ar u
|
||||
raw mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
accessed as an unpartitioned device
|
||||
.Sm off
|
||||
.It Pa /dev/sd Ar u Pa s Ar n
|
||||
.Sm on
|
||||
block mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
slice
|
||||
.Ar n ,
|
||||
accessed as an unpartitioned device
|
||||
.Sm off
|
||||
.It Pa /dev/rsd Ar u Pa s Ar n
|
||||
.Sm on
|
||||
raw mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
slice
|
||||
.ar n ,
|
||||
accessed as an unpartitioned device
|
||||
.It Pa /dev/sd Ns Ar u Ns Ar p
|
||||
block mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
first
|
||||
.Tn FreeBSD
|
||||
slice, partition
|
||||
.Ar p
|
||||
.It Pa /dev/rsd Ns Ar u Ns Ar p
|
||||
raw mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
first
|
||||
.Tn FreeBSD
|
||||
slice, partition
|
||||
.Ar p
|
||||
.Sm off
|
||||
.It Xo
|
||||
.Pa /dev/sd
|
||||
.Ar u
|
||||
.Pa s
|
||||
.Ar n
|
||||
.Ar p
|
||||
.Xc
|
||||
.Sm on
|
||||
block mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
.No Ar n Ns th
|
||||
slice, partition
|
||||
.Ar p
|
||||
.Sm off
|
||||
.It Xo
|
||||
.Pa /dev/rsd
|
||||
.Ar u
|
||||
.Pa s
|
||||
.Ar n
|
||||
.Ar p
|
||||
.Xc
|
||||
raw mode
|
||||
.Tn SCSI
|
||||
disk unit
|
||||
.Ar u ,
|
||||
.No Ar n Ns th
|
||||
slice, partition
|
||||
.Ar p
|
||||
.El
|
||||
.Sh DIAGNOSTICS
|
||||
None.
|
||||
.Sh SEE ALSO
|
||||
.Xr disklabel 1
|
||||
.Xr disklabel 8 ,
|
||||
.Xr fdisk 8 ,
|
||||
.Xr wd 4 ,
|
||||
.Xr disklabel 5
|
||||
.Xr fdisk 1
|
||||
.Xr wd 4
|
||||
.Xr dk 4
|
||||
(on other systems)
|
||||
.Sh HISTORY
|
||||
The
|
||||
.Nm
|
||||
driver appeared in MACH 2.5 .
|
||||
|
||||
driver was originally written for
|
||||
.Tn Mach
|
||||
2.5, and was ported to
|
||||
.Tn FreeBSD
|
||||
by Julian Elischer. Support for slices was written by Bruce Evans.
|
||||
|
||||
Loading…
Reference in New Issue
Block a user