KOPT(8-BSD) RISC/os Reference Manual KOPT(8-BSD)
NAME
kopt - examine or modify kernel parameters
SYNTAX
kopt command
DESCRIPTION
kopt is used examine or modify kernel parameters. The ker-
nel parameters that can be altered are defined in the kernel
table kernargs. Only the super-user may change kernel
parameters via kopt, kernel parameters may be examined by
any user.
command may be one of:
get KERNELPARAM Displays the current value KERNELPARAM.
set KERNELPARAM VALUE
Set KERNELPARAM to VALUE. VALUE must be
an integer expressed in any legal C for-
mat.
bis KERNELPARAM VALUE
Or's VALUE into KERNELPARAM.
bic KERNELPARAM VALUE
Clears the bits indicated by 1's in
VALUE in KERNELPARAM.
The kernel parameters may generally be set from the boot
command line, and their defaults may generally be changed
via binary reconfiguration. The currently defined kernel
parameters, which may be usefully accessed via kopt include
the following:
showconfig If non-zero, drivers print configuration
information at startup time. (Read only.)
machine_type Processor type code. (Read only.)
disable_parity Disable parity checking on machines with par-
ity memory. (Read only.)
cache_bufs Cache disk buffers. (Read only.)
memory_limit Maximum amount of memory to use. (Read
only.)
maxmem Maximum amount of memory being used. (Read
only.)
silo If non-zero, use hardware SILO for serial
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ports, if available. (Read only.)
_posix_chown_restricted
If zero, fchown and chown(2) may not change
the owner of a file, unless executed by the
super-user, and may not change the group of a
file to a group of which the current user is
not a member, unless executed by the super-
user. The default value is -1 (disabled);
setting this parameter to 0 obtains the 4.3
BSD behavior.
_posix_vdisable
If zero, a terminal control character set to
the value 0377 will never match any input
character. If non-zero, an input character
0377 may match a terminal control character
which has been set to that value. The
default is 0 (enabled).
_riscos_group_parent
If zero, a newly created file will have the
group of the directory in which it is
created. If non-zero, a newly created file
will have the principal group of the process
which created it. The default is -1 (dis-
abled); setting this parameter to 0 obtains
the 4.3 BSD behavior.
_riscos_kill_stopped_orphans
If zero and the parent of a traced process
exits, the child will be continued and sent a
SIGKILL signal. If non-zero, the child will
be continued. The default is -1 (disabled);
setting this parameter to 0 obtains the 4.3
BSD behavior.
_riscos_link_owner
If zero, only the owner of a file may create
a hard link to it. If non-zero, any user
with write permission for the file may do so.
The default is -1 (disabled).
_riscos_max_disk_quota_cache
The maximum number of disk quota entries to
be cached by the kernel. One entry is needed
for each logged-in user per file system which
has quotas enabled. Entries are recycled
with an LRU scheme, so a typical maximum
should be employed. Since the quota system
initially starts with zero entries allocated,
no memory will be used if quotas are never
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enabled. The default maximum is machine
dependent.
_riscos_utime_owner
If zero, only the owner of a file (or the
super-user) may use the utime call with
respect to the file. If non-zero, any user
may do so. The default is -1 (disabled);
setting this parameter to 0 obtains the 4.3
BSD behavior.
_riscos_ttys_default_clocal
If enabled, terminal lines default to CLOCAL
enabled for minor devices numbered 0 through
127, and CLOCAL disabled for minor devices
numbered 128 through 255. If the kopt is dis-
abled, the above CLOCAL defaults are
reversed, to more closely match the behavior
of other UNIX systems. (See termio(7-SysV)
for a description of the CLOCAL option.)
RISC/os has adopted the convention that ter-
minal minor device i, 0<=i<=127, is the same
as terminal minor device i+128, except that
the CLOCAL default is inverted for one, rela-
tive to the other. This allows one (CLOCAL
disabled) to be used by default for applica-
tions such as dial-in modems or terminals
which autologout when they are turned off,
and the other (CLOCAL enabled) to be used for
local terminals. The default is 0 (enabled);
set to -1 (disabled) for compatibility with
RISC/os 3.10.
FILES
/usr/src/uts/mips/os/debug.c kernel source file containing
kernargs
/usr/src/uts/mips/master.d/kernel.common
kernel source file containing
default values for many of the
kernel parameters.
DIAGNOSTICS
Various messages about unknown parameters, self-explanatory.
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