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ParaStation5 Administrator's Guide 91
Glossary
Address Resolution Protocol A sending host decides, through a protocols routing mechanism, that it
wants to transmit to a target host located some place on a connected piece
of a physical network. To actually transmit the hardware packet usually
a hardware address must be generated. In the case of Ethernet this is
48 bit Ethernet address. The addresses of hosts within a protocol are
not always compatible with the corresponding hardware address (being
different lengths or values).
The Address Resolution Protocol (ARP) is used by the sending host in
order to resolve the Ethernet address of the target host from its IP address.
It is described in the RFC 826. The ARP is part of the TCP/IP protocol
family.
Administration Network The administration network is used for exchanging (meta) data used for
administrative tasks between cluster nodes.
This network typically carries only a moderate data rate and can be entirely
separated from the data network. Almost always, Ethernet (Fast or more
and more Gigabit) is used for this purpose.
Administrative Task A single process running on one of the compute nodes within the cluster.
This process does not communicate with other processes using MPI.
This task will not be accounted within the ParaStation process
management, ie. it will not allocate a dedicated CPU. Thus, administration
tasks may be startet in addition to parallel tasks.
See also Serial Task for tasks accounted with ParaStation.
admin-task See Administrative Task.
ARP See Address Resolution Protocol.
Data Network The data network is used for exchanging data between the compute
processes on the cluster nodes. Typically, high bandwidth and low latency
is required for this kind of network.
Interconnect types used for this network are Myrinet or InfiniBand, and
(Gigabit) Ethernet for moderate bandwidth and latency requirements.
Especially for Ethernet based clusters, the administration and data
network are often collapsed into a single interconnect.
CPU Modern multi-core CPUs provide multiple CPU cores within a physical
CPU package. Within this document, the term CPU will be used to refer to
a independing computing core, independent of the physical packaging.
DMA See Direct Memory Access.
Direct Memory Access In the old days devices within a computer were not able to put data into
memory on their own but the CPU had to fetch it from them and to store
it to the final destination manually.
Nowadays devices as Ethernet cards, harddisk controllers, Myrinet cards
etc. are capable to store chunks of data into memory on their own. E.g. a
disk controller is told to fetch an amount of memory from a hard disk and