IBM RS/6000 SP, Problem Determination Manual

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This soft copy for use by IBM employees only.
Following are some of the kernel structures that are captured by the system
dump:
System Variables and Statistic
This comprises the kernel parameters either set by
the user or hardcoded into the kernel. Such statistics
include
maxuproc (maximum number of processes
per user), fsize (maximum file size), and stack
(maximum stack segment size).
Process Table
The process table contains a list of all currently
running processes and relevant information about
those processes.
User Areas
This includes more information about the current
running processes on the system. It includes the file
descriptor table.
VFS Information
This includes information about currently mounted
file systems, the inode table and the open file table.
Kernel Stack
The kernel stack keeps the track of all the processes
that were running in kernel mode at that time.
System Buffers
This is the area where incoming data is stored while
awaiting memory allocation from the kernel.
TTY information
Contains information about currently configured ttys,
their characteristics, and current state (including line
discipline).
Mbufs
These are the memory buffers for data which have
been sent/received across the network.
Sockets
A socket is a logical device which can be described
as the end of a pipeline by which network data is
transmitted.
When an unexpected system halt occurs, the system dump facility automatically
copies selected areas of the kernel data to the primary dump device. These
areas include kernel segment 0 as well as other areas registered in the master
dump table by kernel modules or kernel extensions. Memory-resident user data
is also dumped.
AIX version 4 maintains two system dump devices:
Primary Usually used when you wish to save the dump data.
Secondary Can be used to discard dump data (for example, /dev/sysdumpnull).
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SP PD Guide