Red Hat ENTERPRISE LINUX 3 Reference Manual page 89

proc
Chapter 5. The
and
• overflowgid
with system calls on architectures that only support 16-bit group and user IDs.
— Defines the number of seconds the kernel postpones rebooting when the system experi-
• panic
ences a kernel panic. By default, the value is set to
panic.
— This file controls a variety of settings related to printing or logging error messages. Each
• printk
error message reported by the kernel has a loglevel associated with it that defines the importance of
the message. The loglevel values break down in this order:
— Kernel emergency. The system is unusable.
0
•
— Kernel alert. Action must be taken immediately.
1
•
— Condition of the kernel is considered critical.
2
•
— General kernel error condition.
3
•
— General kernel warning condition.
4
•
— Kernel notice of a normal but significant condition.
5
•
— Kernel informational message.
6
•
— Kernel debug-level messages.
7
•
Four values are found in the
6 4 1
Each of these values defines a different rule for dealing with error messages. The first value, called
the console loglevel, defines the lowest priority of messages printed to the console. (Note that, the
lower the priority, the higher the loglevel number.) The second value sets the default loglevel for
messages without an explicit loglevel attached to them. The third value sets the lowest possible
loglevel configuration for the console loglevel. The last value sets the default value for the console
loglevel.
directory — Lists a number of values related to generating random numbers for the kernel.
•
random/
— Configures the maximum number of POSIX realtime signals that the system may
• rtsig-max
have queued at any one time. The default value is
— Lists the current number of POSIX realtime signals queued by the kernel.
• rtsig-nr
— Configures semaphore settings within the kernel. A semaphore is a System V IPC object
• sem
that is used to control utilization of a particular process.
— Sets the total amount of shared memory that can be used at one time on the system, in
•
shmall
bytes. By default, this value is
— Sets the largest shared memory segment size allowed by the kernel, in bytes. By default,
•
shmmax
this value is
33554432
— Sets the maximum number of shared memory segments for the whole system, in bytes.
• shmmni
By default, this value is
— Activates the System Request Key, if this value is set to anything other than the
• sysrq
default.
The System Request Key allows immediate input to the kernel through simple key combinations.
For example, the System Request Key can be used to immediately shut down or restart a sys-
tem, sync all mounted file systems, or dump important information to the console. To initiate a
System Request Key, type [Alt]-[SysRq]-[ system request code ]. Replace
request code
— Disables raw mode for the keyboard and sets it to XLATE (a more limited keyboard mode
r
•
which does not recognize modifiers such as [Alt], [Ctrl], or [Shift] for all keys).
File System
— Defines the fixed group ID and user ID, respectively, for use
overflowuid
file:
printk
7
.
2097152
. However, the kernel supports much larger values than this.
4096
with one of the following system request codes:
, which disables automatic rebooting after a
0
.
1024
71
, the
0
system