PAR Technologies PARASTATION5 V5 - Manual (Page 96)

92 ParaStation5 Administrator's Guide
to store it to a given address. The rest of the jobs is done by this controller
without producing further load to the CPU.
Obviously this concept helps to disburden the CPU from work which is not
its first task and thus gives more power to solve the actual application.
Forwarder See ParaStation Forwarder.
Logger See ParaStation Logger.
Master Node The evaluation of temporary node lists while spawning new tasks is done
only by one particular psid(8) within the cluster. The node running this
daemon is called master node.
The master node is dynamically selected within the cluster and may
change, if the current master node is no longer available. Election is based
on the node IDs, refer to parastation.conf(5).
Network Interface Card The physical device which connects a computer to a network. Examples
are Ethernet cards (which are nowadays often found to be on board) or
Myrinet cards.
NIC See Network Interface Card.
Non-Uniform memory
access (NUMA)
Non-Uniform memory access describes the fact that for some
multiprocessor design the access time to the memory depends on the
location of this memory. Within this designs, the memory is typically closely
attached to a CPU. CPUs have access to memory attached to other CPUs
using additional logic inducing additional latency. Therefore the access
time for different memory addresses may vary.
Parallel Task A bunch of processes distributed within the cluster forming an instance
of a parallel application. E.g. a MPI program running on several nodes
of a cluster can only act as a whole but consists of individual processes
on each node. ParaStation knows about their relationship and can handle
them as a distributed parallel task running on the cluster.
Sometimes also referred as job.
ParaStation Logger The counterpart to the ParaStation Forwarder. This process receives all
output collected by the forwarder processes and sends it to the final
destination, stdout or stderr. Furthermore input to the ParaStation task is
forwarded to a specific process.
The first process of the task started usually converts to the logger
processes after spawning all the other processes of the parallel task.
ParaStation Forwarder Collects output written by ParaStation controlled processes to stdout or
stderr and sends it to the ParaStation Logger.
Furthermore the forwarder controls the process and sends information
about its exit status to the local daemon.
PMI Process Manager Interface: protocol to standardize startup of tasks of a
parallel job. Implemented in mpd and ParaStation5 psid.
Process The atomic part of a Parallel Task. A process is at first a standard Unix
process. Since ParaStation knows about its membership in a parallel task,
it can be handled in a peculiar way if an event takes place on some other
node (e.g. another process of the task dies unexpectedly, a signal is send
to the task, etc.).