Metacat

DataONE Member Node Support

===========================

DataONE_ is a federation of data repositories that aims to improve 

interoperability among data repository software systems and advance the

preservation of scientific data for future use.

Metacat deployments can be configured to participate in DataONE_. This 

chapter describes the DataONE_ data federation,  its architecture, and the 

way in which Metacat can be used to participate as a node in the DataONE system.

.. _DataONE: http://dataone.org/

What is DataONE?

----------------

The DataONE_ project is a collaboration among scientists, technologists, librarians,

and social scientists to build a robust, interoperable, and sustainable system for

preserving and accessing Earth observational data at national and global scales.  

Supported by the U.S. National Science Foundation, DataONE partners focus on

technological, finalncial, and organizational sustainability approaches to 

building a distributed network of data repositories that are fully interoperable,

even when those repositories use divergent underlying software and support different

data and metadata content standards. DataONE defines a common web-service service 

programming interface that allows the main software components of the DataONE system

to seamlessly communicate. The components of the DataONE system include:

* DataONE Service Interface

* Member Nodes

* Coordinating Nodes

* Investigator Toolkit

Metacat implements the services needed to operate as a DataONE Member Node, 

as described below.  The service interface then allows many different scientific 

software tools for data management, analysis, visualization and other parts of 

the scientific lifecycle to directly communicate with Metacat without being

further specialized beyond the support needed for DataONE.  This streamlines the

process of writing scientific software on both for servers and client tools.

The DataONE Service Interface

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

DataONE acheives interoperability

by defining a lightweight but powerful set of web services that can be

implemented by various data management software systems to allow those systems

to effectively communicate with one another, exchange data, metadata, and other

scientific objects.  This `DataONE Service Interface`_

is an open standard that defines the communication protocols and technical 

expectations for software components that wish to participate in the DataONE

federation. This service interface is divided into `four distinct tiers`_, with the 

intention that any given software system may implement only those tiers that are 

relevant to their repository; for example, a data aggregator might only implement

the Tier 1 interfaces that provide anonymous access to public data sets, while

a complete data management system like Metacat can implement all four tiers:

1. **Tier 1:** Read-only, anonymous data access

2. **Tier 2:** Read-only, with authentication and access control

3. **Tier 3:** Full Write access

4. **Tier 4:** Replication target services

.. _DataONE Service Interface: http://releases.dataone.org/online/d1-architecture-1.0.0

.. _four distinct tiers: http://releases.dataone.org/online/d1-architecture-1.0.0/apis/index.html

Member Nodes

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Coordinating Nodes

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Investigator Toolkit

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Metacat as a Member Node

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