SaaS, Utility Computing, Grid
Computing, Pervasive
Computing
Summarized from:Turban, Efraim, Leidner, Dorothy,
Mclean, Ephraim, Wetherbe, James, Information
Technology For Management - Transforming
Organizations in the Digital Economy, John Wiley & Sons,
6th Edition, 2009.
Prepared by Celeste Ng
The SOFTWARE-AS-A-SERVICE
BUSINESS MODEL
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Computing resources are made available to user when
the resources are needed is the Software-as-aService(SaaS) model.
Paid for through a fixed subscription fee, or payable
per an actual usage fee.
To overcome the common challenge to an enterprise
of being able to meet fluctuating demands efficiently.
E.g. utilitycomputing.itworld.com, utilitycomputing.com,
oracle.com/ondemand, Salesforce.com (on demand
service for customer relationship management(CRM))
Prepared by Celeste Ng
SaaS: The Utility Computing Concept
Utility computing is computing that is as
available, reliable, and secure as
electricity, water services ,and telephony.
 Have computing resources available on
demand from virtual utilities around the
globe.
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Prepared by Celeste Ng
Limitations of Utility Computing
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Key pieces of the technology are still missing.
Is hard to do in heterogeneous data centers.
Works better for some applications than for
others.
Needs extra security.
Based on a survey, other concerns include:
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Vendor dependency and lock in(50.8%),
Performance and reliability(45.9%),
Business data too critical to trust to
outsiders(41.6%),
Loss of control over key resources(38.3%)
Prepared by Celeste Ng
GRID Computing
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Coordinates the use of a large number of servers and
storage ,acting as one computer.
Many of the current grid applications are in areas that
formerly would have required supercomputers.
A well-known grid-computing project is the SETI Home
project.
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PC users worldwide donate unused processor cycle times to
help the search for signs of extraterrestrial life by analyzing
signals coming from outer space.
Project to harness the unused processing power of the user’s
computers.
Save the project both money and resources.
Prepared by Celeste Ng
Grid Computing Applications
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„ The Cancer Institute of New Jersey
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With IBM researchers, they use Grid computing to convert
hundreds of thousands of images of cancerous tissues and
cells, from cancer centers around the country, into digital
images
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„ Financial services firm Wachovia Corp.
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‰se grid computing to draw computing power from servers
U
spread across cities in US and London
„ Paypal
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Use grid computing in its electronic payment processing
system
Prepared by Celeste Ng
Pervasive computing
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A future in which computation becomes
part of the environment. Computation will
be embedded in things, not in computers.
Prepared by Celeste Ng