High Performance Computing and Communications Glossary 2.1

A significant part of the material of this glossary was adapted from material originally written by Gregory V. Wilson which appeared as "A Glossary of Parallel Computing Terminology" (IEEE Parallel & Distributed Technology, February 1993), and is being re-printed in the same author's "Practical Parallel Programming" (MIT Press, 1995). Several people have contributed additions to this glossary, especially Jack Dongarra, Geoffrey Fox and many of my colleagues at Edinburgh and Syracuse.

Original version is from NPAC at <URL:http://nhse.npac.syr.edu/hpccgloss/>

Original author: Ken Hawick, khawick@cs.adelaide.edu.au

See also the index of all letters and the full list of entries (very large)

Sections: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


e-cube routing(n.) A message routing algorithm used on binary hypercubes. If <|Sn-1...S0|> and <|Dn-1...D0|> are the binary co-ordinates of the source and destination of the message, and <|Xn-1...X0>| their difference, then the e-cube algorithm routes the message along link parallel to the axes corresponding to 1's in <|Xn-1...X0|>, in order from highest to lowest. See also Metropolis routing, randomized routing.

E1 (n.) The European standard for high speed digital transmission, defined as 2.048Mbps. The E1 has 31 available 64k channels for traffic use. Also refered as a 2Meg, European T1 and CEPT.

eager evaluation (n.) A scheduling policy under which each computation begins as soon as its inputs are ready or its necessary preconditions have been satisfied. This is the scheduling policy used in most programs, but contrasts with the lazy evaluation policy often used in functional and logic programming. See also dataflow, dependence dependence graph.

ECL (n.) Emitter-coupled logic; a high speed, high power transistor technology for chip manufacture. See also BiCMOS, CMOS.

efficiency (n.) A measure of hardware utilization, equal to the ratio of speedup achieved on P processors to P itself. See also isoefficiency, optimality.

EGP (n.) External Gateway protocol is used by gateways in different autonomous systems. EGP allows gateways to share routing information through advertisements.

enumeration sort (n.) a sort that finds the position of each name by determining the number of names smaller than it.

EPROM (n.) Electronically programmable ROM; a memory whose contents can be changed using special hardware. This usually involves removing the chips from their environment in order to "burn" a new pattern into them.

EREW (n.) See PRAM.

ES-IS (n.) End System to Intermediate System is an OSI protocol that allows end systems to announce themselves as intermediate systems. End Systems are equivalent to the internet concept of a host that uses all layers in the communications model. Intermediate Systems are relay communications nodes or forwarders between End Systems and are effectively a subset of End Systems.

ethernet (n.) A LAN protocol that supports high speed communications in the local area. Usually rates are at 10Mbps.

expand(n.) a vector computer instruction that stores the elements of a vector according to the values in a corresponding masking vector.

expected space complexity (n.) the average amount of space used by an algorithm over all possible inputs.

expected time complexity (n.) the average amount of time used by an algorithm over all possible inputs.

explicitly parallel (n.) language semantics that describe which computations are independent and can be performed in parallel. See also implicitly parallel.