PAR Technologies V5 manual Glossary, Arp

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

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