Porting HPC Applications to Grids and Clouds - Cloud, Grid and High Performance Computing: Emerging Applications - page 24

Algorithms, and solve an implicit sparse-matrix
system within each domain, and bundle sets of
'neighboring' domains into super-sets to submit
to the (homogeneous) grid.
Domain Decomposition. This has been dis-
cussed in the paragraphs on Highly Parallel Appli-
cations and on Explicit versus Implicit Algorithms.
Job Mix . Last but not lease, one of the most
trivial but most widely used scenarios often found
in university and research computer centers is
the general job mix, stemming from hundreds or
thousands of daily users, with hundreds or even
thousands of different applications, with varying
requirements for computer architecture, data han-
dling, memory and disc space, timing, priority, etc.
This scenario is ideal for a Grid which is managed
by an intelligent Distributed Resource Manager
(DRM), for example GridWay (2008) for a global
grid, Sun Grid Engine Enterprise Edition (Chaubal,
2003) for an enterprise grid, or the open source
Grid Engine (2001) for a departmental Grid or a
simple cluster. These DRMs are able to equally
balance the overall job load across the distributed
resource environment and submit the jobs always
to the best suited and least loaded resources. This
can result in overall resource utilization of 90%
and higher.

secure access to Grid services (computers, storage,
data, applications, etc). The main goal of a Grid
portal is to hide the details and complexity of the
underlying Grid infrastructure from the user in
order to improve usability and utilization of the
grid, greatly simplifying the use of grid-enabled
applications through a user-friendly interface.
Grid portals have become popular in research
and the industry communities. Using Grid portals,
computational and data-intensive applications
such as genomics, financial modeling, crash
test analysis, oil and gas exploration, and many
more, can be provided over the Web as tradi-
tional services. Examples of existing scientific
application portals are the GEONGrid (2008)
and CHRONOS (2004) portals that provide a
platform for the Earth Science community to study
and understand the complex dynamics of Earth
systems; the NEESGrid project (2008) focuses on
earthquake engineering research; the BIRN portal
(2008) targets biomedical informatics researchers;
and the MyGrid portal (2008) provides access to
bioinformatics tools running on a back-end Grid
infrastructure. As it turns out, scientific portals
are usually being developed inside specific re-
search projects. As a result they are specialized
for specific applications and services satisfying
project requirements for that particular research
application area.
In order to rapidly build customized Grid
portals in a flexible and modular way, several
more generic toolkits and frameworks have been
developed. These frameworks are designed to
meet the diverse needs and usage models arising
from both research and industry. One of these
frameworks is EnginFrame, which simplifies
development of highly functional Grid portals
exposing computing services that run on a broad
range of different computational Grid systems.
EnginFrame (Beltrame, 2006) has been adopted
by many industrial companies, and by organiza-
tions in research and education.

Applications and Grid Portals

Grid portals are an important part of the process
of grid-enabling, composing, manipulating, run-
ning, and monitoring applications. After all the
lower layers of the grid-enabling process have
been performed (described in the previous para-
graphs), often, the user is still exposed to the many
details of the Grid services and even has to take
care of configuring, composing, provisioning,
etc. the application and the services “by hand”.
This however can be drastically simplified and
mostly hidden from the user through a Grid por-
tal, which is a Web-based portal able to expose
Grid services and resources through a browser to
allow users remote, ubiquitous, transparent and