Base Concepts: Pragmatic Object Web
3-(or more)-tier architecture - Web browser front-ends, legacy (e.g. databases, HPC modules) backends; fat (1+tier) middleware
Alternative / competing Middleware models:
- Java - single language solution by Sun
- CORBA - all languages solution by OMG
- COM - multi-language solution by Microsoft
- XML - emergent universal data solution by the W3C
POW attempts at integrating various models in terms of multi-protocol middleware servers (JWORB)