gprof. A UNIX command that produces an execution
profile of C, Pascal, Fortran, or COBOL programs. The
execution profile is in a textual and tabular format. It is
useful for identifying which routines use the most CPU
time. See the man page on gprof.
GUI (Graphical User Interface). A type of computer
interface consisting of a visual metaphor of a real-world
scene, often of a desktop. Within that scene are icons,
representing actual objects, that the user can access
and manipulate with a pointing device.
H
SP Switch. The high-performance message passing
network, of the IBM RS/6000 SP(SP) machine, that
connects all processor nodes.
HIPPI. High performance parallel interface.
hook. hook is a pdbx command that allows you to
re-establish control over all task(s) in the current context
that were previously unhooked with this command.
home node. The node from which an application
developer compiles and runs his program. The home
node can be any workstation on the LAN.
host. A computer connected to a network, and
providing an access method to that network. A host
provides end-user services.
host list file. A file that contains a list of host names,
and possibly other information, that was defined by the
application which reads it.
host name. The name used to uniquely identify any
computer on a network.
hot spot. A memory location or synchronization
resource for which multiple processors compete
excessively. This competition can cause a
disproportionately large performance degradation when
one processor that seeks the resource blocks,
preventing many other processors from having it,
thereby forcing them to become idle.
I
IBM Parallel Environment for AIX. A program
product that provides an execution and development
environment for parallel FORTRAN, C, or C++
programs. It also includes tools for debugging, profiling,
and tuning parallel programs.
installation image. A file or collection of files that are
required in order to install a software product on a IBM
RS/6000 workstation or on SP system nodes. These
files are in a form that allows them to be installed or
removed with the AIX installp command. See also
fileset
,

Licensed Program Product

, and
package
.
Internet. The collection of worldwide networks and
gateways which function as a single, cooperative virtual
network.
Internet Protocol (IP). 1) The TCP/IP protocol that
provides packet delivery between the hardware and
|user processes. 2) The SP Switch library, provided with
the Parallel System Support Programs, that follows the
IP protocol of TCP/IP.
IP. See

Internet Protocol

.
J
Jacobi-Seidel. See

Gauss-Seidel

.
|job management system.
|The software you use to manage the jobs across your
|system, based on the availability and state of system
|resources.
K
Kerberos. A publicly available security and
authentication product that works with the Parallel
System Support Programs software to authenticate the
execution of remote commands.
kernel. The core portion of the UNIX operating system
which controls the resources of the CPU and allocates
them to the users. The kernel is memory-resident, is
said to run in

kernel mode

(in other words, at higher
execution priority level than

user mode

) and is protected
from user tampering by the hardware.
L
Laplace's equation. A homogeneous partial
differential equation used to describe heat transfer,
electric fields, and many other applications.
The dimension-free version of Laplace's equation is:
The two-dimensional version of Laplace's equation may
be written as:
190 IBM PE for AIX V2R4.0: Messages