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mcicap(4)
NAME
mcicap - media changer capability database
SYNOPSIS
/etc/mcicap
DESCRIPTION
The mcicap file is a database consisting of media changer descriptions.
Each entry within the mcicap file describes a specific media changer, or a
model of media changer.
The entries within the mcicap file are used by certain functions within the
media changer driver software. For example, entries are necessary for all
media changers that you plan on accessing with the mcutil command.
An mcicap file entry has the following form:
name|alt_name|another_alt_name:capability:capability: ...
This form is described as follows:
· The vertical bars (|) are part of the entry.
· Fields are separated by colons (:).
· The first field lists all names that are used for the particular media
changer, separated by vertical bars (|). The first name (name) is the
most common abbreviation for the media changer. The first and second
names should contain no blanks. The third name (another_alt_name) is
optional and may contain blanks for readability; it should be a long
name, fully identifying the media changer.
· Following the media changer's names are its capabilities. Each
capability is separated by a colon (:). Capabilities may be in any
order, and are described in the following section.
· An entry may continue onto multiple lines by inserting a backslash (\)
as the last character of the line that you wish to continue.
Capabilities
The capabilities that you list in an mcicap file entry each consist of
two-letter codes, possibly followed by further information. The various
capabilities fall under three categories:
Boolean capabilities
The capability code, if present in the entry, means that the media
changer has a particular feature. For example, the HP100 media changer
has auto-eject. Therefore, the entry for a HP100 media changer includes
the ae code.
Numeric capabilities
The capability code must be followed by a pound sign (#) and a number.
For example, the following ns capability code setting indicates that
there are 144 slot elements:
ns#144
String capabilities
The capability code must be followed by an equal sign and a string.
The string must be enclosed within double quotes if it contains any
whitespace; otherwise, double quotes are optional. For example, the
following dt capability code setting indicates that the data transfer
unit is a disk type:
dt=disk
Capability Codes
A listing of all capability codes appears in this section. For clarity,
the following conventions are used:
· Boolean capability codes are shown exactly as they would appear in an
entry (as a two-letter code)
· Numeric capability codes are followed by #n
· String capability codes are followed by =string
The following is a list of all capability codes:
ae Auto-eject. Indicates that the media changer does not need to send an
explicit eject sequence to a drive when the drive is the source of a
move or exchange operation.
br Bar code reader. Indicates that the media changer has the ability to
return the bar code information printed on the medium. The information
is returned in the volume tag field (the last field) in the output of
the element status function. The element status function is the -e
option to the mcutil command.
dn=string
Device names. Contains a list (separated by commas) of the device
names for the accessible drives. If the first character of a device
name is a slash (/), then the name is a full path to the device. If
the first character of a name is not a slash, then the /dev directory
path is assumed as a prefix. For example, the following are equivalent
device name capability code settings:
dn="mc0,mc5"
dn="/dev/changer/mc0, /dev/changer/mc5"
dt=string
Data transfer unit type. Contains the disk or tape string. This
information is needed for the eject command if the device requires an
explicit eject operation. It is useful to provide this information
regardless of the status of the auto-eject capability because the
mcutil command can be used to provide configuration information.
Including the dt capability field could provide the mcutil command, and
therefore the user, with more information.
ex Exchange medium. Indicates that the media changer supports the
exchange medium capability as stated in the SCSI-II standards
documentation.
ia=string
Interface arguments. Contains interface-specific information. Media
changers using the scsi2 interface type do not use this field. The
uagent interface requires the bus target and logical unit number (LUN)
identifiers of the media changer. For example, the following interface
argument setting is for a device on bus 0, target 1, and LUN 1:
ia="0 1 1"
is Initialize element status. Indicates that the media changer supports
an initialize element status capability as stated in the SCSI-II
standards documentation.
it=string
Interface type. Specifies the interface type to connect to the media
changer. Currently, the scsi2 and uagent interface types are
supported. The scsi2 interface type uses the SCSI CAM Media Changer
interface (see mc(7)) and therefore requires the SCSI CAM Media Changer
Driver to be built into the running kernel. The uagent interface
requires the CAM systems uagent driver, which is contained in any
kernel running the SCSI CAM system. The /dev/cam pseudo device is
required and is used by the uagent driver to communicate with the media
changer.
ls Log select/sense. Indicates that the media changer supports a logging
interface capability as stated in the SCSI-II standards documentation.
mc=string
Media changer device file. Names the device file that is used for
controlling the media changer. For the scsi2 interface type it is the
device file that connects to the SCSI CAM Media Changer Driver. For the
uagent interface, the /dev/cam file is almost always used.
MD=range
MP=range
MS=range
MT=range
Physical maps. Maps the physical addresses of the slot (MS), drive
(MD), port (MP), and transport (MT) elements to their logical
addresses. Most SCSI-II compliant media changers provide element
address information so these entries are not required. The use of
physical map codes within an mcicap file entry is indicated when your
jukebox is not SCSI-II compliant, or when you wish to override the
jukebox addressing. By overriding the jukebox addressing you could,
for example, prevent a particular drive from being used. If you wish
to provide physical mapping information, see your jukebox hardware
manual for the physical addresses of the elements.
The range value can be one of the following:
+
A range from a lower number to a higher number, indicated by using a
minus sign (-). For example, the following MS code setting indicates
that the physical address for the slot elements are 116, 117, 118, and
119:
MS=116-119
+
A list of numbers or ranges separated by commas. For example, the
following MD code setting indicates that the physical addresses for the
drive elements are 111, 112, 113, 114, 115, 311, 210, 211, and 212:
MD=111-115,311,210-212
The media changer driver software maps logical addresses to
physical addresses. For each element type (slot, drive, port, or
transport) the logical addresses are mapped to the physical
addresses consecutively starting at logical address zero.
The following are examples of address mappings:
MS=116-119
Maps the physical slot addresses 116, 117, 118, and 119 to the logical
slot addresses 0, 1, 2, and 3.
MD=111-115,311,210-212
Maps the physical drive addresses 111, 112, 113, 114, 115, 311, 210,
211, and 212 to the logical drive addresses 0, 1, 2, 3, 4, 5, 6, 7, and
8.
Note that for the above examples to map exactly as depicted, you
should indicate in your mcicap file entry the precise number of
elements. In other words, the two previous examples should
include the following capability code settings in the mcicap file
entries:
ns#4
nd#9
Defaults for Mapping
If the quantity of a type of element or its physical addresses
are not provided within an mcicap file entry, then the jukebox is
queried by the driver software. If the quantity of a type of
element becomes known to the driver software but not all (or
none) of the physical addresses become known, then the "missing"
physical addresses are assumed to be the same as the
corresponding logical addresses.
ms Mode select/sense. Indicates that the media changer supports a mode
select/sense capability as stated in the SCSI-II standards
documentation.
ns#n
Number of slots. Specifies the number of slot type elements. The
media changer, when queried by the media changer driver, may provide
the number of slot type elements that it supports. The ns capability
code setting overrides the number provided by the media changer.
nd#n
Number of drives. Specifies the number of drive type elements. The
media changer, when queried by the media changer driver, may provide
the number of drive type elements that it supports. The nd capability
code setting overrides the number provided by the media changer.
np#n
Number of import/export ports. Specifies the number of port type
elements. The media changer, when queried by the media changer driver,
may provide the number of port type elements that it supports. The np
capability code setting overrides the number provided by the media
changer.
nt#n
Number of transports. Specifies the number of transport type elements.
The media changer, when queried by the media changer driver, may
provide the number of transport type elements that it supports. The nt
capability code setting overrides the number provided by the media
changer.
pa Prevent/allow functionality. Indicates that the media changer supports
a prevent/allow capability as stated in the SCSI-II standards
documentation.
pe Position-to-element. Indicates that the media changer supports a
position-to-element capability as stated in the SCSI-II standards
documentation.
rd Read diagnostics. Indicates that the media changer supports a read
diagnostics capability as stated in the SCSI-II standards
documentation.
re Read element status. Indicates that the media changer supports a read
element status capability as stated in the SCSI-II standards
documentation.
rs Release/reserve element. Indicates that the media changer supports a
release/reserve element capability as stated in the SCSI-II standards
documentation.
tc=string
Type compatible entry field. Equates the string value to the first
name of a previous entry in the mcicap file. The entry in which the tc
field exists is compatible (has the same capabilities) as a previously
defined entry - the entry indicated by the string value. This allows
capabilities which are associated with the media changer model to be
defined once, while the more specific media changer information - such
as that regarding connectivity and device naming - is defined with each
individual media changer's logical name. For a sample of how to use
the tc field see the EXAMPLE section near the end of these reference
pages.
ts Two-sided medium. Indicates that the jukebox media is double sided;
also indicates that the media changer transport mechanism can perform
an invert operation.
vt Volume tag. Indicates that the jukebox returns volume tag information
(when valid) as part of the output for the element status function.
The element status function is the -e option to the mcutil command.
Preparing Descriptions
The amount of information that must be provided in the mcicap file entry is
dependent on the particular jukebox. It is possible to have a very short
entry because the media changer can provide certain information. For
example, the HP100 is typical of most SCSI-II compliant media changers
because the number and address of each element can be provided by the media
changer. Therefore, that information is not required in the mcicap file
entry. Some jukeboxes require an explicit command to eject the media from
the drive before a move from a drive can be accomplished. Therefore, for
some jukeboxes, you must provide certain information within the mcicap file
entry - information such as device names - that allows for particular media
changer operations. Such an operation would be opening a drive and giving
the eject command.
If an mcicap file entry provides information that the media changer also
provides, the mcicap file entry takes precedence. For example, if the
media changer states it has X number of slots, the mcicap file entry for
that media changer changes that number by providing a ns capability code
setting. In this way you can, for example, make the HP100 media changer
look and act like it has fewer slots available.
The most effective way to prepare a media changer description is by
imitating the description of a similar media changer in the mcicap file;
then build up a description gradually. To check the validity of a
particular media changer description, use the mcutil command. To test a
new media changer description, set the MCICAP environment variable to the
path name of the file containing the description. The mcutil command reads
that file rather than the /etc/mcicap file. The MCICAP environment
variable can also be set to the mcicap file entry (to avoid having the
mcutil utility read a file). See the mcutil reference page for more
information.
RESTRICTIONS
A very unusual media changer may expose deficiencies in the ability of the
mcicap file to describe it. Also, an unusual media changer may expose
deficiencies in the mcutil command.
EXAMPLES
The following entry, which describes the TL800, is typical of an entry in
the mcicap file:
TL800|backup_tape_changer|remote_backup_TC:
:ae:re:is:ls:pe:pa:rs:
:dt=tape:
:mc=/dev/mc9:it=scsi2:dn="/dev/changer/mc9":
FILES
/etc/mcicap
File containing media changer descriptions.
RELATED INFORMATION
Commands: mcutil(1)
Files: mc(7)
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Alphabetical
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