master
Purpose
Contains master configuration information.
Description
The master file is an attribute file that contains
stanzas that describe all device drivers defined in the
system. There are two kinds of stanzas, AIX device
driver stanzas and Virtual Resource Manager (VRM) driver
stanzas. AIX driver stanzas specify drivers to link into
the kernel and the VRM drivers that support them. VRM
driver stanzas specify drivers to be loaded into the VRM
at the time the system is loaded.
The use of extended characters in the master file is not
supported.
The sysparms Stanza
The first stanza of the /etc/master file, the sysparms
stanza, defines the values for many system parameters and
limits. If you need to modify any of these system param-
eters, first make the changes in the /etc/master file,
then rebuild the kernel. See Device Driver Development
Guide for instructions on rebuilding the kernel.
callouts Specifies the number of callouts the kernel
uses for event waiting.
charlists Specifies the number of character lists the
terminal driver uses.
connections Specifies the maximum number of concurrent
network connections allowed for Distributed
Services.
Note: This keyword sets the size of the
node table in the kernel.
drivernkprocs Specifies the maximum number of kernel
processes available for a given device
driver. To create this kind of keyword,
replace driver with an abbreviation for the
device driver, then follow it with the
letters nkprocs. (For example,
"tcpipnkprocs".)
Note: A keyword ending with the letters
nkprocs should be defined in the
/etc/master file for any device driver that
needs to allocate kernel processes.
dsnkprocs Specifies the maximum number of kernel
defined processes available for use by Dis-
tributed Services.
dumpdev Specifies the target device for kernel
dumps.
filetab Specifies the number of entries in the
kernel open file table.
floating Indicates whether the kernel should attempt
to use floating-point hardware, if it is
present. Options in this parameter are
hardware and software. The default, soft-
ware, means there is no optional floating-
point accelerator hardware.
hashbuffers Specifies the number of hash buffers the
kernel uses.
hftbuffers Specifies the number of virtual terminals.
inodetab Specifies the number of entries in the
kernel i-node table.
iobuffers Specifies the number of physical I/O
buffers the kernel supports.
kbuffers Specifies the number of disk buffers in the
kernel. If kbuffers is not defined, or if
it is set to 0, then the system chooses the
number of buffers based on the processor
and the amount of real memory installed in
the system.
kdmabuffers Specifies the number of buffer headers used
by the exec system call. The default value
is 32.
kmap Specifies the number of elements in
resource map array for internal kernel
storage.
kprocs Specifies the number of kernel defined
processes the kernel supports.
maxprocs Specifies the maximum number of processes
for each terminal session.
mountab Specifies the number of entries in the
mount table used by the kernel for file
system mounting. This value sets the limit
of the number of file systems that can be
mounted by the kernel. See "mnttab" for
details.
msgmap Specifies the locations of fragments of
free storage used for message text.
msgmax Specifies the maximum number of bytes
allowed in a single message.
msgqid Specifies the maximum number of message
queue identifiers allowed.
msgqmax Specifies the maximum number of bytes
allowed on a message queue.
msgseg Specifies the maximum number of message
segments allocated per message from the
msgmap area. This number must be less than
32,768.
msgsegsize Specifies the message segment size (in mul-
tiples of word size).
msgtql Specifies the text queue length (the total
number of active messages throughout the
system at any one time).
nflocks Specifies the maximum number of simultane-
ously locked file regions.
netnoone Specifies the Distributed Services user ID
or group ID value to use when no user ID
from the local node maps to a remote file's
owner ID. The default value is 0xFFFF.
netsomeone Specifies the Distributed Services user ID
or group ID value to use when more than one
local ID maps to a remote file's owner ID,
and one particular ID cannot be selected
(for example, because of wild card map-
pings). The default value is 0xFFFE.
nid Specifies the node ID to generate into the
system. This keyword is currently unused.
nncb Specifies the size of the Distributed Ser-
vices translate table array. Each node for
which the kernel has user ID or group ID
translate information has an entry in this
array of translate headers.
node Specifies the node name to generate into
the system.
pinkbuffers Specifies whether or not the disk buffers
should be pinned. The value can be true or
false.
pipedev Names the stanza that defines the file
system used for FIFO files.
power Indicates whether the kernel has power
warning code. If this value is true, power
warning code exists. The default is false.
procs Specifies the total number of simultaneous
processes the kernel supports.
pslotkill Specifies the threshold at which the system
begins to kill processes in order to
recover paging space. pslotkill is speci-
fied in slots, where a slot is 2048 bytes
(four blocks) of a paging minidisk. The
default value is 200 slots.
pslotpanic Specifies the threshold at which to stop
AIX and attempt a system dump because
paging space has almost been exhausted.
Note that the system dump itself cannot
finish because of the lack of paging space.
pslotpanic is specified in slots, where a
slot is 2048 bytes (four blocks) of a
paging minidisk. The default value is 100
slots.
pslotwarn Specifies the threshold at which the system
displays a message warning that paging
space is running low. When the system dis-
plays this message, it also:
o Performs a sync to write all changes to
disk
o Enters sync mode, in which disk I/O is
not buffered
o Sends all processes the SIGDANGER
signal to warn them that the system is
likely to "crash" any moment.
pslotwarn is specified in slots, where a
slot is 2048 bytes (four blocks) of a
paging minidisk. The default value is 350
slots.
ptybuffers Specifies the number of pseudo-terminals
that can be present in the system (see
"pty"). The maximum value for ptybuffers
is 256, while the default value is 16.
release Specifies the operating system release
number to generate into the system.
rootdev Names the stanza in the /etc/system file
that defines the root file system device.
rsbuffers Specifies the number of buffers allocated
for the asy terminal driver.
semadjmax Specifies the maximum value allowed for
semaphore adjust value on exit.
semid Specifies the number of distinct semaphore
identifiers the kernel supports.
semmap Specifies the number of entries in
semaphore map array.
semmax Specifies the maximum number of simul-
taneous semaphores allowed and supported by
the kernel.
semopmax Specifies the maximum number of operations
allowed for each semop system call.
semsetmax Specifies the maximum number of semaphores
allowed in a set.
semunmax Specifies the number of semaphore undo
structures the kernel supports.
semunpmax Specifies the maximum number of undo
entries for each process.
semvalmax Specifies the maximum value allowed for
each semaphore.
shmid Specifies the number of distinct shared
memory identifiers the kernel supports.
shmmax Specifies the maximum number of kilobytes
for shared memory allowed per shared
segment.
shmmin Specifies the minimum number of kilobytes
for shared memory allowed per shared
segment.
shmsegs Specifies the number of segment registers
that may be used to support shared memory.
slice Specifies the percentage of time in quanta
that a process can run before it must
relinquish control of the processor. Each
quantum on the RT PC system is equal to 333
milliseconds.
system Specifies the system name to generate into
the system.
texttab Specifies the number of shared text segment
entries in the the text table.
version Specifies the version number of the oper-
ating system to generate into the system.
AIX Driver Stanzas
There is a unique set of keywords associated with each
type of stanza. It is not necessary, however, for a
stanza to contain all the keywords associated with that
type. If a keyword is omitted from the stanza, the
default is used. Mandatory keywords must be supplied and
are not defaulted. The name of each stanza is a logical
AIX driver name referenced in other stanzas.
The lines interpreted by the config and vrmconfig com-
mands are:
config Indicates that this device has a
customization helper program, which pro-
vides assistance in decoding other options.
This value is the name of the helper
program in the /etc directory. See
"config" for more information about
customization helper programs.
major Identifies the major device number for this
driver. This is mandatory.
mandatory Identifies this driver to be included
whether or not the system file asks for it.
If this value is true, include this driver.
maxminor States the maximum number of minor devices
this driver supports. This number should
agree with the driver code.
mpx Identifies a multiplexed special file when
this value is true.
prefix Provides a prefix for the driver routines.
For example, if this value is "abc", then
the open routine in the driver is
"abc"open. This keyword is mandatory.
Note that all drivers are assumed to be
archived into the system object libraries.
routines Identifies the routines actually defined
for this driver. The possible routines are
open, close, read, write, strategy, ioctl,
init, and print.
tty Identifies whether the device is a ter-
minal. If this value is true, the device
is a terminal and terminal structures are
defined.
vdriver Names the VRM driver stanzas for the
related VRM drivers.
Other lines can be included for interpretation by
customization helper programs.
VRM Driver Stanzas
The iocn lines identify VRM driver stanzas. The name of
each stanza is a logical VRM driver name referenced in
other stanzas.
The lines interpreted by the vrmconfig command are:
code Specifies the full path name of the file
containing executable VRM code that con-
tains the table of contents format of the
VRM driver.
copy Names a previously specified VRM driver
stanza to be used instead of the code
keyword specification.
ctype Indicates the code type, such as vdrvr.
This is an informational keyword for IBM
customization helpers.
iocn Assigns the decimal I/O code number to this
driver.
protocol If the value is true, indicates that this
stanza describes a protocol procedure.
Other lines can be included for interpretation by
customizaton helper programs.
Miscellaneous System Parameters
Both the master and the system file can have option lines
describing miscellaneous system customizing and tuning
options in the sysparms stanzas. Options in the system
file override those in the master file. These options
include:
inetlen Specifies the Internet packet length for
file transfer. (See the xftp command in
Interface Program for use with TCP/IP.)
The default value is 1064 bytes.
level Specifies the level number of the operating
system to generate into the system.
msgheader Specifies the maximum number of system
message headers allowed.
Other keywords can be added as needed.
Example
The following sample of a master file entry contains AIX
Operating System and VRM information.
* AIX drivers, identified by "major" keyword
* printer drivers
u5182mp:
major = 6
prefix = lp
routines = open,close,write,ioctl,init
maxminor = 8
vdriver = v5182mp
config = vrcmain
u5182sp1:
major = 6
prefix = lp
routines = open,close,write,ioctl,init
maxminor = 8
vdriver = v5182sp1
config = vrcmain
u5182sp2:
major = 6
prefix = lp
routines = open,close,write,ioctl,init
maxminor = 8
vdriver = v5182sp2
config = vrcmain
* VRM driver entries
v5182mp:
iocn = 2014
code = /vrm/vrmdd/vpptr
ctype = vdrvr
v5182sp1:
iocn = 2015
code = /vrm/vrmdd/vpptr
ctype = vdrvr
v5182sp2:
iocn = 2016
code = /vrm/vrmdd/vpptr
ctype = vdrvr
File
/etc/master
Related Information
In this book: "mount," "vmount," "mnttab," "attributes,"
"system," and "pty."
The vrmconfig and config commands in AIX Operating System
Commands Reference.