ddr.dbase - Text database file of SCSI CAM device definitions
/etc/ddr.dbase
Dynamic Device Recognition (DDR) is a framework for
describing the operating parameters and characteristics of
SCSI devices to the SCSI CAM I/O subsystem. You use a
utility, /sbin/ddr_config, and a text database,
/etc/ddr.dbase, to make changes to the subsystem after
installation and without rebooting.
This dynamic device recognition capability replaces the
static methods of device recognition that have been
employed by using the compiled-in device table,
/sys/data/cam_data.c. SCSI devices in the
/sys/data/cam_data.c file are supported for this release
of the operating system, but support will be withdrawn in
a future release.
The ddr.dbase file contains device specifications for the
SCSI CAM devices. To manage these devices, you edit the
ddr.dbase file to contain new or changed device information.
After you have made changes to the ddr.dbase file,
you run the ddr_config utility, which compiles a new version
of the database, places the output in the /etc/ddr.db
binary database file, and notifies the kernel that the
device database has changed. Subsequently, the kernel
synchronizes its in-memory device tables with the
/etc/ddr.db binary database file.
The ddr.dbase file is an ASCII file and it is shipped on
the distribution medium already populated with general
syntax and entries for supported devices and templates for
other devices.
Semantics, element definition, and formats conform to the
specifications of
SCSI-2, SMALL COMPUTER SYSTEM INTERFACE - 2
(X3.131-1994).
General Syntax Rules [Toc] [Back]
The following list contains the general syntax rules for
entries in the ddr.dbase file: Comments: Text starting
with the # character is a comment until the end of the
line. Whitespace: Leading and separating whitespace is
ignored. Identifiers: Identifiers must be fully specified;
are case insensitive. Integers: Integers can be
specified as decimal, hexadecimal (when preceded with 0x),
or octal (when preceded with 0). Tokens: All tokens are
case insensitive. All tokens must be fully specified,
with the exception of Yes and No tokens, which are recognized
by the first letter only. Strings: Strings are
case sensitive when enclosed by quotes. Otherwise,
strings are converted to lowercase.
Database Structure [Toc] [Back]
There are three parts to the ddr.dbase file: A VERSION
data section One or more GLOBAL data sections One or more
SCSIDEVICE data sections
Each of these sections is identified by a keyword.
VERSION Data Section [Toc] [Back]
The VERSION data section defines which version of the
ddr.dbase syntax the file conforms to. The syntax for the
section keyword is: VERSION = version
The first line in the ddr.dbase file that is not a comment
line must contain this version keyword and string.
GLOBAL Data Section [Toc] [Back]
The GLOBAL data section contains information used by the
device data sections for two classes of attributes: disk
partition sizes and tape density settings.
The object of the global partition information is to allow
the kernel to create a default partition layout based on a
disk's capacity and block size. You specify global information
in this data section to change the defaults for
disk devices.
The object of the global SCSI density code translation
table for tapes is to define the density values (bpi) and
blocking factors for the SCSI density codes that are
obtained from tape devices.
You can use the strings defined in the density tables to
specify SCSI density codes to the subsequent SCSIDEVICE
subsections of this file instead of explicitly stating the
integer values in the SCSIDEVICE subsections.
The GLOBAL data section syntax is as follows. The first
data line in a global data section contains the GLOBAL
keyword. The lines following the GLOBAL keyword line contain
data lines. Each data line contains a single data
element. Excepting as noted in the following discussion,
data lines can be specified in any order, or omitted. The
GLOBAL data section that contains the SCSI density code
translation table must precede all SCSIDEVICE data section
lines in the ddr.dbase file.
The PARTITION data line syntax is as follows. Each PARTITION
data line consists of an identity equated to a value.
In the /ddr.dbase file for VERSION 1, there are four data
lines and they are:
Partition_A_size = 64
Partition_B_size = 128
Partition_G_size = 400
min_partition_size = 50 If any of these values are not
specified, they default to values compiled into the system.
The density code translation table syntax is as follows.
The first data line in a density code translation table
must be the specification for the size of the table, an
identity equated to a value. For VERSION 1, this data
line must be:
scsi_density_table_size = 0x30 There must be at least
one subsequent entry in the table. These data lines are
specified as an identifier and density code equated to a
density name string, a bpi value, and a block size value
(in bytes). The general format for these data lines is:
scsi_tape_density[density_code] = "name" bpi
block_size The data lines can be specified in any order.
If an element in a data line is not specified, it is
assigned a NULL value. A block_size of zero indicates
that the default blocking factor for the device is used
and variable-size record blocking is allowed.
SCSIDEVICE Data Section [Toc] [Back]
The first data line in a SCSI device data section must
contain the SCSIDEVICE keyword. There must be a SCSIDEVICE
data section for each device to be defined in the
ddr.dbase file.
The next two data lines are also required: they define
the vendor, product, and revision names that identify the
device. Specifies one of the device types defined in the
ddr.dbase file: disk tape printer processor worm rodirect
cdrom scanner optical changer comm Specifies the SCSI vendor
identification string, and optionally, the SCSI product
identification string and product version string.
SCSIDEVICE Subsections [Toc] [Back]
Each SCSI device data section is divided into subsections
identified by the following keywords:
PARAMETERS: Subsection
Entries in this subsection specify the operational parameters
for SCSI devices. The syntax rules are:
The first line in the parameters section must contain the
PARAMETERS: keyword.
The lines following the PARAMETERS: keyword contain data
lines. Each data line contains a single data element.
Data lines can be specified in any order, or omitted.
Data lines that are not specified inherit the values of
the default device entry for the device type. Specifies a
subclass of the device type. Valid only for disks and
tapes.
For disk devices, specify class as one of the following
strings: hard_disk cdrom floppy_3.5
floppy_5.25 Additionally, for disk devices, specify
the attribute string raid to indicate that the disk
is functioning as a raid storage device.
For tape devices, specify class as one of the following
strings: 9trk qic 8mm 3480 DLT rdat Additionally,
for tape devices, specify the attribute
string loader to indicate that the tape unit also
has an attached loader that does not have a separate
target id. That is, the tape unit is at one
lun on the target and the loader is at another lun
on the target. Physical record size of the device,
in bytes. Maximum transfer size allowed for the
device, in bytes. If the device supports bad block
recovery, enable or disable the feature. Valid
only for disk devices. If the device supports synchronous
transfers, enable or disable the feature.
If the device supports wide transfers, enable or
disable the feature. The device has a configurable
geometry (or capacity) that may change during run
time. If the device supports SCSI bus disconnects,
enable or disable the feature. Allow the underlying
SIM to reorder CCBs by enabling or disabling
the feature. If the device supports Tagged Queuing,
enable or disable the feature. The number of
simultaneously active tagged requests the device
supports. Range is 0 to 255. The device is capable
of running with its write-back cache enabled.
Valid for disk devices only. The device is capable
of being spun down and back up for power management.
Do select timeout retries. The time, in
seconds, to delay between power on and device ready
states. The device supports the Prevent/Allow command
(Opcode 0x1E). The device supports the
Reserve and Release commands (Opcodes 0x16 and
0x17). The device supports the write verify command
(Opcode 0x2E). [Note that use is limited to
RAID devices, specifically the HSZ10 and HSZ15.]
The tagged request queue is to be distributed
across all luns on the device. Size of Inquiry
data buffer to allocate for device. Range is 0 to
255. Size of Request Sense data buffer to allocate
for device. Range is 0 to 255.
MODESELECT: Subsection
Some devices require mode selects to be sent to a device
the first time that it is accessed so that the device can
be placed in a known operational state. The CAM subsystem
supports up to eight mode selects to be sent to the
device.
The MODESELECT: subsection specifies the data for a single
mode select. Only the 6-byte mode select command, the
mode select header, (optionally) an 8-byte block descriptor,
and a single page of data, is supported.
Up to eight mode select subsections can be specified for a
device. The order in which the mode selects are sent to
the device is based on the value of the ModeSelectNumber
field (see below). Mode select number 0 will be sent
first, followed by 1, and so on. The mode select number
for each Mode Select subsection must be unique, and there
must not be any holes (for example, you cannot define mode
select numbers 1 and 3 without defining mode select number
2).
Each line in this subsection contains a single element of
data.
The first line must contain the MODESELECT: keyword.
The following data lines must be specified, and must precede
any optional data lines specified. These data lines
may be specified in any order. Specifies the relative
position that this mode select is to be issued to the
device. Range is 0 to 7. The SP field (Byte 1 Bit 0) of
the Mode Select Command. Specifies if the Mode Select
data is to be saved by the device. The PF field (Byte 1
Bit 4) of the Mode Select Command. Identifies which Page
format specification the mode select conforms to. Specify
Yes to send an 8-byte block descriptor. Specify No to
prevent an 8-byte block descriptor from being sent. The
Parameter List Length field (byte 4) of the Mode Select
Command. Specifies the length of mode select data to be
transferred, in bytes. This value should include the size
of the Mode Parameter Header, Block Descriptor, and the
Page Data. Using this value, the subsystem calculates the
Page Length entry for the Page data. Range is 0 to 255.
The following data lines are optional. If an entry is not
specified, the device data inherits the value of zero for
the entry. The data lines can be specified in any order.
The Medium Type field (Byte 1) of the Mode Parameter
Header. Range is 0 to 255. The Device-Specific Parameter
field (Byte 2) of the Mode Parameter Header. This identifier
is to be used whenever the device is not a tape or
disk. Range is 0 to 255. The Speed field (Byte 2 Bits
0-3) of the Mode Parameter Header. Range is 0 to 15. Use
this identifier only with tape devices. The Buffered Mode
field (Byte 2 Bits 4-6) of the Mode Parameter Header.
Range is 0 to 7. Use this identifier only with tape
devices. The Density Code field (Byte 0) of the Block
Descriptor. Specify this identifier only when the BlockDescriptor
value is Yes. This identifier is accepted if
the device type is specified as tape, cdrom, or optical.
Range is 0 to 255. Note: for tape devices, the actual
strings and values that are accepted are in the GLOBAL
section, in the SCSI density code translation table.
The following string values are accepted for cdrom
devices: "default" => 0x00 = Default density.
"dataonly" => 0x01 = User data only.
2048 bytes per sector.
"dataaux" => 0x02 = User data, Aux data.
2336 bytes per sector.
"tagdataaux" => 0x03 = 4byte tag, User data, Aux
data. 2340 bytes per sector.
"audio" => 0x04 = Audio Information
Only.
1/75th of a second per
block. The following string values are accepted
for optical devices: "default" => 0x00 =
Default density Specify this identifier only when
the BlockDescriptor value is Yes. The Number of
Blocks field (Bytes 1-3) of the Block Descriptor.
Range is 0 to 16777215 (2^24 - 1). Specify this
identifier only when the BlockDescriptor value is
Yes. The Reserved field (Byte 4) of the Block
Descriptor. Range is 0 to 255. Specify this identifier
only when the BlockDescriptor value is Yes.
The Block Length field (Bytes 5-7) of the Block
Descriptor. Range is 0 to 16777215 (2^24 - 1).
Used to set a byte quantity within the Page Data.
Range for index is 0 to (<TransferLength> - 11).
Range for integer is 0 to 255. Used to set a short
quantity within the Page Data. Range for index is
0 to ((<TransferLength> - 11)/2). Range for integer
is 0 to 65535. Used to set an int quantity
within the Page Data. Range for index is 0 to
((<TransferLength> - 11)/4). Range for integer is
0 to (2^32 - 1). Used to set a long quantity
within the Page Data. Range for index is 0 to
((<TransferLength> - 11)/8). Range for integer is
0 to (2^64 - 1).
DENSITY: Subsection
The CAM subsystem support for tape devices allows specific
densities (including the enabling of compression, and so
on), to be selected when accessing the tape. When reading
a tape, the device may override the density selected by
autoselecting a density based on the media present The
densities are selected based on the bits 1-3 of the minor
device number for the tape device (/dev) node (bit 0 being
the rewind/no-rewind indicator). Thus, eight different
densities may be selected.
Currently, device nodes are made for only 4 of the 8
possible density values (0-3), which are reflected in the
device node name by the suffixes (low), h (high), m
(medium), and a (alternate) respectively.
This subsection specifies the density information that is
sent to the device via a mode select (with the Device Configuration
Page) in order to set the tape density. The
assignment of density to minor bit values done via the
DensityNumber field (see below). Up to eight density subsections
may be specified for one device.
Each line within this subsection contains a single element
of data.
The first data line in the density subsection must contain
the DENSITY: keyword.
After the DENSITY: data line, the The following data line
must be specified, and must precede any optional data
lines Specifies the density bit values in the minor device
number that this density subsection corresponds to. The
values for this density subsection may apply to multiple
minor device numbers by specifying each applicable number
in a comma separated list. Range for integer is 0 to 7.
The following data lines are optional. If a data line is
not specified, the device data inherits the value of zero
for the entry. The data lines can be specified in any
order. Specify Yes to write only one file mark when closing
the device. Specify no to write two file marks when
closing the device. The Speed field (Byte 2 Bits 0-3) of
Mode Parameter Header sent to the device. Range is 0 to
15. The Buffered Mode field (Byte 2 Bits 4-6) of the Mode
Parameter Header sent to the device. Range is 0 to 7.
The Density Code field (Byte 0) of the Block Descriptor
sent to the device. Range of integer is 0 to 255. The
strings from the global section density table (tape only)
are valid here for densitystring. The Number of Blocks
field (Bytes 1-3) of the Block Descriptor that is sent to
the device. A NULL value (zero) means variable size.
Range is 0 to 16777215 (2^24 - 1). The Select Data Compression
Algorithm field (Byte 14) of the Page data for
Page Code 0x10 (Device Configuration Page). Range is 0 to
255.
ATTRIBUTE: Subsection
The CAM subsystem now allows for device-specific
attributes to be specified for a device. These attributes
are not used by the CAM subsystem; they are provided as
vendor-specific hooks for third party drivers.
This subsection specifies data for a single attribute. Any
number of attribute subsections may be specified for a
device.
Each line within this subsection contains a single element
of data.
The first line of data in the attribute subsection must
include the ATTRIBUTE: keyword.
After the ATTRIBUTE: keyword is specified, The following
data lines must be specified, and must precede any
optional data lines specified. These data lines may be
specified in any order. A string specifying the name of
the attribute. Strings are case sensitive when enclosed
by quotes. Otherwise, strings are converted to lowercase.
The length, in bytes, of the attribute data.
The following data lines are optional. If an entry is not
specified, the attribute data inherits the value of zero
for the entry. The data lines can be specified in any
order. Used to set a byte quantity within the attribute
data. Range for index is 0 to (<Length> - 1). Range for
integer is 0 to 255. Used to set a short quantity within
the attribute data. Range for index is 0 to ((<Length> -
1)/2). Range for integer is 0 to 65535. Used to set a
int quantity within the attribute data. Range for index
is 0 to ((<Length> - 1)/4). Range for integer is 0 to
(2^32 - 1). Used to set a long quantity within the
attribute data. Range for index is 0 to ((<Length> -
1)/8). Range for integer is 0 to (2^64 - 1). Used to set
the contents of the attribute data to the contents of a
text string. The length of the string must be no longer
than (<Length> - 1). Any attribute data beyond the end of
the string will be set to zero. Strings are case sensitive
when enclosed in quotes. Otherwise, strings are converted
to lowercase. [Note: the string contained in the
attribute data will always be null-terminated).
See the /etc/ddr.dbase file for examples of use.
The binary database file of SCSI device definitions
/sbin/ddr_config The utility that compiles the
/etc/ddr.dbase file into the
/etc/ddr.db file
Commands: ddr_config(8)
Hardware Management
Files: disktab(4).
SCSI-2, SMALL COMPUTER SYSTEM INTERFACE - 2 (X3.131-1994)
delim off
ddr.dbase(4)
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