Glossary of terms

AFS

Andrew File System - distributed network file system

CAE

Computer Aided Engineering

CCMM

Computational Chemistry and Molecular Modeling

CESNET

association of universities and Czech Academy of Sciences for development of academic computer network

CFD

Computational Fluid Dynamics

CPU

Central Processing Unit - processor, the part of a computer performing computations. The more a computer has CPUs, the more tasks can perform simultaneously.

CSM

Computational Structural Mechanics

FAQ

Frequently Asked Questions

FTP

File Transfer Protocol

Géant

pan-European communication network with speeds in the order of Gigabits per second

HEP

High Energy Physics

HPC

High Performance Computing

Kerberos

a system for authentization, named after three-headed dog guarding the gate to the Underworld in the Greek mythology

MPI

Message Passing Interface - programming interface for communication between parallel processes. If an aplication uses MPI, it can run on clusters as well as on SMP machines, just the MPI implementation must be changed.

PBS

Portable Batch System - a system for load sharing and scheduling on multiprocessor machines

PDA

Personal Digital Assistent - a computer so small that it fits into a palm

PDF

Portable Document Format

RT system

Request Tracking system

SMP

Symmetric MultiProcessing - architecture of a multiprocessor machine, where all CPUs are equal and are sharing one copy of operating system. When compared to clusters, it is easier to write applications for SMP machines due to the shared memory and OS, but SMP machines are more expensive for the same number of CPU than clusters

UNIX

originaly a trademark of a concrete operating system, today the word is used for many similar operating systems like Linux, FreeBSD, OpenBSD, NetBSD, Sun Solaris, SGI IRIX, HP-UX, OSF/1 anf others. In that meaning Unix is the most used operating system on servers.

authentization

verification of identity

authorization

decision, if an authentized object has the right to do a given task

cluster

a group of many nearly identical computers, with the same operating system, user accounts, with shared disks and interconnected with high-speed network. Together with a load sharing system like PBS they can be treated like one computer, but the nodes do not share memory. When compared to SMP machines, clusters are cheaper.

grid

from "I. Foster, C. Kesselman. -The Grid: Blueprint for a New Computing Infrastructure": "A computational grid is a hardware and software infrastructure that provides dependable, consistent, pervasive, and inexpensive access to high-end computational capabilities."

login

a username, short string of english letters and digits, identifying a user, like "joe"

myrinet

a trademark of special highspeed network cards for interconnecting cluster nodes

scalar processors

usual processors working with numbers in the form of individual values. They are fast for common tasks like word-processing, compilation or web browsing, but slower for operations with matrices than vector processors

SSH

Secure SHell - a safe variant of telnet

supercomputer

a computer more powerful than other contemporary computers. The definition is moving over time, so that todays common computers can be more powerful than supercomputers of the past. Todays supercomputers have many CPUs, while todays common computers just one or two.

telnet

protocol for text-based connection to a remote computer. It is not secure , as passwords are passed unencrypted.

vector processors

processors optimalized for operations with matrices. Can be slow for common tasks like word-processing, compilation or web browsing.

virtual

not existing in reality, only apparently

Grid terms

GIIS

Grid Index Information Service - information service collecting information from local GRIS

GRIS

Grid Resource Information Service - information service providing information about concrete machine (CPU, OS, memory, load, running jobs,...)

MDS

Monitoring and Discovery Service - implementation of GIIS and GRIS of Globus project

GRAM protocol

Grid Resource Access Management protocol - protocol for running jobs, for communication with Gatekeeperem

Gatekeeper

daemon for running jobs, communicates with GRAM protocol

RSL

Resource Specification Language - language for jobs specification, uses form of LDAP filters, e.g. &(executable = /bin/ls)(arguments = -l)

LDAP

Lightweight Directory Access Protocol - protocol for access to directory services, objects in a directory are identified by their DN

GSI

Grid Security Infrastructure

X509v3 certificate

digital certificate, i.e. public crypting key accompanied by person/object DN, together digitally signed by Certification Authority, in format specified by X509v3 norm

DN

Distinguished Name - unambiguous object name composed from a sequence of fields, e.g. /C=CZ/O=Masaryk University/OU=SCB/CN=Martin Kuba describes an object in country CZ, in organization Masaryk University, v organizational unit SCB, with name (Common Name) Martin Kuba

OGSA

Open Grid Services Architecture - specification of grid services i.e. web services with added operations and defined life cycle

OGSI

Open Grid Services Infrastructure - first implementation of OGSA in Globus 3, currently replaced by WSRF

WSRF

Web Services Resource Framework - implementation of OGSA in Globus 4