This is a static archive of the previous Open Grid Forum Redmine content management system saved from host redmine.ogf.org file /dmsf_files/8020?download= at Thu, 03 Nov 2022 23:16:30 GMT Basic WG charter info

Data Format Description Language (DFDL) Working Group

Global Grid Forum, Data Area

Chairs:

Martin Westhead, M.Westhead@epcc.ed.ac.uk

Guy Rixon, gtr@ast.cam.ac.uk

Alan Chappell, chappella@battelle.org

Secretary(s)

Martin Westhead, M.Westhead@epcc.ed.ac.uk

 

Email list:

dfdl-discuss@nesc.ac.uk

Web page:

www.epcc.ed.ac.uk/dfdl/

Charter:

Focus/Purpose

XML provides an essential mechanism for transferring data between services in an application and platform neutral format. However it is not well suited to large datasets with repetitive structures, such as large arrays or tables. Furthermore, many legacy systems and valuable data sets exist that do not use the XML format. The aim of this working group is to define an XML-based language, the Data Format Description Language (DFDL), for describing the structure of binary and character encoded (ASCII/Unicode) files and data streams so that their format, structure, and metadata can be exposed. This effort specifically does not aim to create a generic data representation language. Rather, DFDL endeavors to describe existing formats in an actionable manner that makes the data in its current format accessible through generic mechanisms.

 

The DFDL description would sit in a (logically) separate file from the data itself. The description would provide a hierarchical description that would structure and semantically label the underlying bits. It would capture:

Further, if the data file contains highly repetitive structures, such as large arrays or tables, such a description can be very concise.

 

The potential benefits to having such a standard include:

Goals/Milestones

The goals of the group are as follows:

  1. To develop a proposal for a standard Data Format Description Language (DFDL) which will consist of a general structure description language and then an extensible set of ontologies for which we will provide a base.
  2. To work with other groups within the GGF to ensure that the DFDL proposal conforms with other emerging Grid standards.
  3. To foster the development of reference implementations of libraries and tools that use the DFDL proposal.

The group aims to be very focused and to leverage existing implementation work (see references) in the development of reference implementations. As such our aim would be to complete the work in 18 months. We propose to produce the following documents:

  1. Formal language for DFDL structure description

  2. XML representation of this language (XML Schema, including standard APIs to reference it)

  3. Requirements for DFDL ontology - what features are required of a DFDL ontology

  4. Basic types ontology (floating point, integer, character etc.)

  5. Basic structures ontology (Strings, arrays, tables etc.).

 

Milestones:

 

References:


This is a static archive of the previous Open Grid Forum Redmine content management system saved from host redmine.ogf.org file /dmsf_files/8020?download= at Thu, 03 Nov 2022 23:16:30 GMT