Information Technology Reference
In-Depth Information
• Integrators, that offer advanced management services that spread over several
Clouds or Hybrid Clouds
• Aggregators that offer a single common interface to multiple Cloud providers.
The integration and advances in interoperability of Clouds might be an important
factor for the future success of Cloud Computing. Open standards and interoper-
ability among Private and Public Clouds enable a higher flexibility for user compa-
nies. The user companies would be able to also partly outsource data and processes
to the Cloud that are less security- and privacy-sensitive. At the same time, the
possibility to build a Federation of Clouds would enable specialization of single
Clouds as well as a broader choice for the users.
4.6 Grid and Cloud Computing Compared
The description of Grid Computing in Chapter 3 and Cloud Computing in this
chapter show that there are many similarities among Grid and Cloud Computing.
This has provoked many discussions in commercial and scientific literature around
the question if Grids and Clouds are the same, if Cloud Computing is only a new
marketing hype, or if there are substantial differences between Grid and Cloud
Computing.
Currently, the discussion about differences among Grid and Cloud Computing
mainly regards technical aspects (see also table 4.3).
Table 4.3:
Grid and Cloud Computing technically compared
Grid Computing
Cloud Computing
Means of utilisation
(e.g. Harris 2008)
Allocation of multiple servers
onto a single task or job
Virtualization of servers; one server
to compute several tasks concur-
rently
Typical usage pattern
(e.g. EGEE 2008)
Typically used for job execution,
i.e. the execution of a programme
for a limited time
More frequently used to support
long-running services
Level of abstraction
(e.g. Jha et al. 2008)
Expose high level of detail
Provide higher-level abstractions
Foster et al. (2008) for example identify differences among Grid and Cloud
Computing in various aspects as security, programming model, compute model,
data model, application and abstraction. According to Merrill Lynch (2008), what
makes Cloud Computing new and differentiates it from Grid Computing is virtuali-
zation: “Cloud computing, unlike grid computing, leverages virtualization to maxi-
mize computing power. Virtualization, by separating the logical from the physical,
resolves some of the challenges faced by grid computing” (Merrill Lynch 2008).
While Grid Computing achieves high utilization through the allocation of multiple
servers onto a single task or job, the virtualization of servers in Cloud Computing
achieves high utilization by allowing one server to compute several tasks concur-
rently (Harris 2008). Beside these technological differences between Grid and
