Red Hat ENTERPRISE LINUX 4.5.0 Reference Manual page 102

Chapter 5. The proc File System
• — 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
random/
kernel.
• — Configures the maximum number of POSIX real-time signals that the system
rtsig-max
may have queued at any one time. The default value is
• — Lists the current number of POSIX real-time signals queued by the kernel.
rtsig-nr
• — Configures semaphore settings within the kernel. A semaphore is a System V IPC
sem
object 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
shmall
system, in pages. By default, this value is
• — Sets the largest shared memory segment size allowed by the kernel, in bytes. By
shmmax
default, this value is
• — Sets the maximum number of shared memory segments for the whole system, in
shmmni
bytes. By default, this value is
• — Activates the System Request Key, if this value is set to anything other than zero
sysrq
( ), the default.
0
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 system, sync all mounted file systems, or dump important information to the
console. To initiate a System Request Key, type Alt-SysRq-
Replace
<system request code>
78
file:
printk
7
2097152
. However, the kernel supports much larger values than this.
33554432
4096
with one of the following system request codes:
.
1024
.
<system request code>
.