CAT
Component Architecture Toolkit. A software layer above a grid that enables end users to make use of the Grid services in order to build and run distributed component-based applications.

Grid
A grid is a software framework providing layers of services to access and manage distributed hardware and sofware resources. NASA's IPG (Information Power Grid) effort is an example of a Grid.

CORBA ORB
The communication mechanism layer of the CORBA framework that abstracts away communication from application components.

HPC++
A compiler/runtime system that supports the global pointer abstraction and supports a library toolkit for high-performance parallel C++.

Open HPC++
Implementation of HPC++ that gives the end-user more direct control over the communication mechanisms.

CCAT
Common Component Architecture Toolkit.

LDAP
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Legion
Distributed Programming model provides an architecture and language.

Globus
Low-level library toolkit that enables programmers (not end users) to program to the Grid. Globus is a composition of services.

Nexus
Communication library and protocol underlying Globus