Emerging grids could help bridge the gap between grid technologies and
users. The classification of grid systems aims to motivate research and
help establish a foundation in this developing field. The grid started
in the early '90s as a model of metacomputing in which supercomputers
share resources; subsequently, researchers added the ability to share
data. This is usually referred to as the first-generation grid. By the
late '90s, researchers had outlined the framework for second-generation
grids, characterized by their use of grid middleware systems to 'glue'
different grid technologies together. Third-generation grids originated
in the early millennium when Web technology was combined with
second-generation grids. As a result, the invisible grid,2 in which grid
complexity is fully hidden through resource virtualization, started
receiving attention. Subsequently, grid researchers identified the
requirement for semantically rich knowledge grids,2 in which middleware
technologies are more intelligent and autonomic. Recently, the necessity
for grids to support and extend the ambient intelligence vision has
emerged. In AmI, humans are surrounded by computing technologies that
are unobtrusively embedded in their surroundings However, third-generation
grids' current architecture doesn't meet the requirements of
next-generation grids (NGG) and service-oriented knowledge utility (SOKU).
In the literature, two characteristics categorize traditional grids: the
type of solutions they provide and the scope or size of the underlying
organization(s). We propose four additional nomenclatures to facilitate
the classification of emerging grids: accessibility, interactivity,
user-centricity, and manageability. We define each of these features
and explain our rationale for adding them... To make the NGG a reality,
researchers must address some critical aspects and serious challenges,
such as infrastructure agnostic grid middleware, dynamic service
composition, user-centricity, dependability, security, and scalability.
Some open ethical and philosophical concerns are striking as well.
Although grid technologies never had an explicit goal of changing our
society, it's likely that emerging grids will have long-term consequences
and ethical values (such as those relating to security and privacy) that
are much more influential than the Internet.