PAPER 23 In "The Physiology of the Grid..." Foster, Kesselman, Nick, Tuecke 
present the Open Grid Services Architecture (OGSA) which seeks to 
provide a standard architecture for integrating resources of "virtual 
organizations".  OGSA is meant to describe the "physiology" of the grid, 
defining functionality, while Globus (an open-source grid computing 
toolkit) is meant to describe the "anatomy" of the grid, defining 
protocols.  These resources could be computational, network, storage, 
etc.  The authors begin by presenting the evolution of grid services 
along two dimensions.  The first is distribution.  Today services are 
highly distributed across the country or the world and highly 
hetrogenous in scale and platform.  The second is application.  Grid 
computing was originally targeted at scientific collaboration, but today 
integrates between businesses and customers and between businesses.  The 
rest of the paper presents OGSA.  OGSA defines a large-scale 
architecture providing many services from discovery to remote invokation 
to authentication, authorization and auditing.  OGSA does not define 
implementations, but instead identifies interfaces, composition of 
services and requires uniform semantics of similar services.  OGSA 
defines these semantics through a set of interfaces and conventions 
(such as lifetime management and service handle definitions) much as the 
Java specification and API does.  OGSA doesn't define a system or even a 
reference implementation (although Globus does).  Instead OGSA provides 
an open standard for businesses and other organizations to conform to in 
order to interoperate with one-another.  Because the scope of OGSA is so 
large, providing a distributed interaction protocol for very large-scale 
system integration, it's hard to tell it's strengths and weaknesses. 
Obviously there are issues that will arise, one of which is adoption. 
Time will tell if OGSA provides the needed standards.  Ultimately the 
contribution of OGSA is almost a political one, rather than technical, 
instead relying on existing technologies (web services, HTTP, etc.).

In "On Death, Taxes, and the Convergence..." Foster and Iamnitchi 
compare the work of the grid computing field and peer-to-peer systems. 
Specifically, grid is defined as being structured and reliable.  Systems 
are assumed to be well-known (at least relatively to peer-to-peer). 
These systems perform a wide variety of diverse services to clients and 
are long-lived.  Clients may aggregate arbitrary state within the grid 
over a long period of time.  And this state may be shared with other 
clients who might use it to aggregate different state elsewhere within 
the grid.  Peer-to-peer systems on the other hand are said to be 
application specific, providing specific short-lived services.  A single 
peer-to-peer system might be large, but each node provides a single 
service, and clients are said not to aggregete intermediate state in the 
network for use later or by other clients.  Instead peer-to-peer systems 
are resilient to failures, do not depend on administrative organization 
and nodes may be unknown to the vast majority of other nodes.  Foster 
and Iamnitchi hope that these fields will (and argue that they must) 
converge on systems and techniques that combine the benefits of both 
fields.  That is, systems which provide the rich and diverse services, 
aggregation of arbitrary intermediate state, and collaboration between 
clients of grids with the robust, resilient and self-organizing 
properties of peer-to-peer systems.  Just as OGSA makes a 
meta-contribution to the field, this paper too argues for adoption and 
identifies opportunites for integration of work already existing.

