Proc/Buddyinfo; Proc/Cmdline - Red Hat ENTERPRISE LINUX 5 - DEPLOYMENT Deployment Manual

1.16 1.2 0x07 0x01 0xff 0x80 -1% -1 ?
Running the apm -v command on such a system results in output similar to the following:
APM BIOS 1.2 (kernel driver 1.16ac) AC on-line, no system battery
For systems which do not use a battery as a power source, apm is able do little more than put the
machine in standby mode. The apm command is much more useful on laptops. For example, the
following output is from the command cat /proc/apm on a laptop while plugged into a power outlet:
1.16 1.2 0x03 0x01 0x03 0x09 100% -1 ?
When the same laptop is unplugged from its power source for a few minutes, the content of the apm
file changes to something like the following:
1.16 1.2 0x03 0x00 0x00 0x01 99% 1792 min
The apm -v command now yields more useful data, such as the following:
APM BIOS 1.2 (kernel driver 1.16) AC off-line, battery status high: 99% (1 day, 5:52)

3.2.2. /proc/buddyinfo

This file is used primarily for diagnosing memory fragmentation issues. Using the buddy
algorithm, each column represents the number of pages of a certain order (a certain size) that are
available at any given time. For example, for zone DMA (direct memory access), there are 90 of
2^(0*PAGE_SIZE) chunks of memory. Similarly, there are 6 of 2^(1*PAGE_SIZE) chunks, and 2 of
2^(2*PAGE_SIZE) chunks of memory available.
The DMA row references the first 16 MB on a system, the HighMem row references all memory greater
than 4 GB on a system, and the Normal row references all memory in between.
The following is an example of the output typical of /proc/buddyinfo:
Node 0, zone DMA
Node 0, zone Normal
Node 0, zone HighMem

3.2.3. /proc/cmdline

This file shows the parameters passed to the kernel at the time it is started. A sample /proc/
cmdline file looks like the following:
ro root=/dev/VolGroup00/LogVol00 rhgb quiet 3
90 6 2
1650 310 5
2 0 0
1 1 ...
0 0 ...
1 1 ...
/proc/buddyinfo
17