The Gateway project is an effort to build computational web portals that allow users to access high performance computing facilities via web browsers such as Netscape and Internet Explorer.† The goal of Gateway is to provide a high level user interface that simplifies access to various computing resources maintained by computing centers with varying access and security policies.† Gateway provides a commodity-based solution to these problems, taking advantage of the multi-billion dollar investment of the commercial sector into such technologies and standards as CORBA, XML, and Java.†
The Gateway design consists of three tiers, with the aforementioned browser interface serving as the first tier.† The functionality of the front end is provided by middle tier software (WebFlow), which acts as a command broker for various services.† These services can be implemented directly by the middle tier software, or else the middle tier can act as a proxy for accessing backend services.† Back end services can be queuing systems for high performance computers, databases, mass storage systems, or metacomputing services such as Globus.††
The WebFlow middle tier software is extensible and can be extended by module developers.† Standard modules commonly used by clients include:
A reference implementation for the front end is currently in development phase and includes the following features built using the standard modules:
Gateway is a system-centric portal, providing tools that simplify running codes in different environments and on different HPC platforms.† It is designed to work with applications for which the source code is not available.† It further makes the assumption that the codes have already been parallelized. This design is influenced by the funding entities (ASC and ARL MSRC), which make extensive use of commercial codes and have a separate effort (CHSSI) for parallelizing codes.† Gateway concentrates instead on providing a uniform interface for scientist who use the facilities of multiple centers with different access policies.† Gateway helps users submit jobs to different queuing systems, tracks running jobs on many different hosts, and provides tools transferring files between the userís desktop and the remote system.† As a system-centric portal, it is compatible with and complementary to code-centric portals such as Cactus.
Gateway front end software is in developmental phase and is not yet available for download.† Middle tier (WebFlow) source code is available for download from the Gateway web site.