[DFDL-WG] Latest draft of DFDL 1.0 specification

Wed Sep 11 10:08:41 EDT 2013

Alan

Thanks for your reply. I forgot to say that the next call is on Tues 17th 
September.

I think that the WG would probably go for your 2nd suggestion, ie, publish 
an updated P_REC that obsoletes GFD.174 but does not yet propose to 
promote the spec to full recommendation status, because we know there are 
a few more errata that will be discovered before the implementations are 
completed.

When you say 'new version' what does that imply about version numbers? The 
WG still considers what we are working on to be DFDL 1.0 plus errata. Are 
you suggesting that the new revision is 1.1 ?

Regards

Steve Hanson
Architect, IBM Data Format Description Language (DFDL)
Co-Chair, OGF DFDL Working Group
IBM SWG, Hursley, UK
smh at uk.ibm.com
tel:+44-1962-815848

From:   "Sill, Alan" <alan.sill at ttu.edu>
To:     Steve Hanson/UK/IBM at IBMGB, "David E. Martin" 
<martinde at northwestern.edu>, 
Cc:     "Sill, Alan" <alan.sill at ttu.edu>, "dfdl-wg at ogf.org" 
<dfdl-wg at ogf.org>, Greg Newby <gbnewby at alaska.edu>
Date:   11/09/2013 14:51
Subject:        Re: Latest draft of DFDL 1.0 specification

Steve,

Answers inline. Short summary: My recommendation would be to publish a new 
version that obsoletes the current GFD.174, and optionally to use this 
opportunity to migrate the specification from a P-REC to full REC status. 
This would be facilitated by documenting, in any form that is convenient 
including but not limited to an informational GFD, the experience gained 
from implementations to date. Another option is to publish an updated 
P_REC that obsoletes GFD.174 but does not yet propose to promote the spec 
to full recommendation status.

On Sep 11, 2013, at 6:47 AM, Steve Hanson <smh at uk.ibm.com>
 wrote:

> Alan 
> 
> Since the DFDL 1.0 specification was published in Feb 2011, the two 
implementation teams (IBM and the Daffodil project) have identified a 
number of errata in the specification. These have been recorded in an 
errata document held on Redmine. The number of errata is currently at 
around 190, and include both clarifications to the specification and 
changes that affect an implementation, both major and minor. Typically as 
errata have been raised, the implementation teams include any implied 
changes in the next release of their implementation. 

Is there any documentation as to the experience gained from 
implementations that has led to these updates? I as not as an OGF 
requirement, but just for information.

> Both implementation teams, and users of the two implementations, have 
requested that the DFDL 1.0 specification is revised to include all errata 
to date, so that the specification more closely reflects the 
implementations. Accordingly all errata to date have been incorporated 
into a new revision of the specification, which as a result has grown from 
168 pages to 234 pages. 
> 
> This new revision of the specification supersedes the original.

This statement is what leads to my suggestion to publish a new document. 
Note that our procedures do allow for replacement of a REC or P-REC for 
non-normative changes that do not substantially affect compatibility of 
implementations, but that just clarify or correct errors in the original 
publication. It is the statement that the new revision supersedes the 
original coupled with your earlier observation that major implementation 
issues are addressed in your new version that causes me to suggest that 
you pursue a new GFD that obsoletes the old one.

> There is no implementation that exactly reflects the original as 
published on the OGF web site, they both adhere more closely to the new 
revision. The DFDL WG would therefore like to publish the new revision. 
The DFDL WG also recognises that there may be comments against the new 
revision, and that there may still be some errata undetected by the 
implementation teams, so that a further revision may be necessary in the 
future. Nonetheless it is important that the new revision in its current 
form is externally visible, and not just kept as an internal working 
document, as there are now many dozens of DFDL users, and they need an 
up-to-date specification. In particular, IBM DFDL wants to ship the HTML 
version of the new revision to IBM customers in its next release. 
> 
> We are looking to the OGF for guidance on how next to proceed. 

My guidance would be to publish a new version that obsoletes the old one, 
and optionally to use this opportunity to advance the specification from 
P-REC to REC status.  Note that this is exactly the pattern that OGF 
documents are supposed to follow in the life cycle described in GFD.152 -- 
experience gained fro real-world implementation is fed back to produce a 
new version of the specification, which at some point can declare itself 
to be mature enough to request full REC status.

As for further revisions, they would be handled by the procedure I 
mentioned above: non-normative changes can be folded in as corrections 
through the errata process. THis is controlled by the OGF editor (Greg 
Newby) and whether to accept and publish an errata is decided essentially 
entirely by his recommendation to the GFSG (Standards Council) to do so. 
If the changes would affect the interoperability of implementations 
written to the earlier spec in a substantial way, they should be handled 
by the process of a new publication that obsoletes the old one, as we have 
just discussed.

The process of going from a P-REC to a REC is largely decoupled from 
errata revisions, but as I have tried to point out, you may be in a 
position do do this at thei point - especially if the group were to 
publish its experiences with the spec as one or more informational 
documents to provide a paper trail motivating the proposed changes.  (This 
part is your choice on how to produce the documentation, which does not 
have to be in the form of a GFD but can and often is done this way. The 
experiences of each group can be jointly or separately documented, at your 
group's choice.)

> Would it be possible for the OGF to join our next DFDL WG call to 
discuss further? The call is at 16:00 UK (11:00 Eastern). 

If today, I can do this if you provide connection details. I include David 
Martin in this reply in case he is available.

Alan

> Regards
> 
> Steve Hanson
> Architect, IBM Data Format Description Language (DFDL)
> Co-Chair, OGF DFDL Working Group
> IBM SWG, Hursley, UK
> smh at uk.ibm.com
> tel:+44-1962-815848
> Unless stated otherwise above:
> IBM United Kingdom Limited - Registered in England and Wales with number 
741598. 
> Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 
3AU

Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 
741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU
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