1 Chapter 1. Application development overview This chapter provides an overview of the programming environment on Blue Gene/L. It discusses general items of interest to an application developer, while answering the following questions: What is the Message Passing Interface (MPI) implementation on Blue Gene/L? What are the major concerns an application developer should keep in mind when writing applications for Blue Gene/L? Where are the supporting files (compilers, include, and link files) located, and what versions are they? © Copyright IBM Corp. 2006, 2007. All rights reserved. 1