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Discussion document: some non-trivial uses of DFDL
by Robert E. McGrath 23 Sep '05

23 Sep '05

As I have been studying the DFDL and working on the primer, I have been thinking about how it might be used in Grid applications. A virtual walk around NCSA has produced quite a few non-trivial use cases. What I would like to do is put some of these out to the group, for discussion. Since I am relatively new to the DFDL game, I expect that some of my ideas are naive or flat wrong. I have typed up detailed notes on 4 cases. I have a couple of other cases I'm trying to document. I attach these notes here. Sorry, it's a bit long! -- --- Robert E. McGrath, Ph.D. National Center for Supercomputing Applications University of Illinois, Urbana-Champaign Urban, Illinois 61820 (217)-333-6549 mcgrath(a)ncsa.uiuc.edu

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[Fwd: BOUNCE dfdl-wg@ggf.org: Non-member submission from ["Dave Berry" <daveb@nesc.ac.uk>]]
by Martin Westhead 23 Sep '05

23 Sep '05

Forwarded from Dave Berry, advertising a BOF on Data streams at GGF.

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F2F logistics - IBM Copley Place offices
by Mike Beckerle 23 Sep '05

23 Sep '05

During the upcoming GGF15 we'll be having a concurrently scheduled F2F meeting. This meeting will be hosted by IBM at its Boston facility. I have booked Conference Room 101 for Monday, Tuesday, and Wednesday all day. This seats 10 and has a speakerphone, network connection, whiteboard. I have booked Conference Room 102 for Tuesday and Wednesday all day. This seats 4 and is for smaller side discussions breakouts. It also has a speakerphone, network connection, can't recall about whiteboard. I think so. I will bring a LCD projector for slide showing. Here's information on the physical location: This map shows both Copley place where IBM's office is, and the Park Plaza Hotel (where GGF15 is being held). http://maps.google.com/maps?q=Copley+Place.+Boston+MA&ll=42.348855,-71.0739… Here's a google earth image where I've put graffiti marking the Park Plaza Hotel where GGF15 is being held, and the Copley Place complex where IBM's offices are. It's 3.5 blocks walking. It is barely worth a cab ride unless it's raining. Don't bother with the subway either. The walks to/from the subway are the same distance as walking directly. Copley place has two buildings. We're in "2" Copley place, though I don't think your average person on the street knows which building is 1 and which is 2. Number one has a Westin hotel and some shopping. If you enter there you'll need to take the walkway across to the other building which has the larger bulk of the shopping, Neiman Marcus dept. store, and the Marriott hotel, oh...and the IBM offices. Here's another Google Earth picture showing the Copley Place Buildings, which the hotels are, and roughly where in the complex you'll find IBM's offices. Once you are in the correct building, go to the very center of Copley Place Mall and look for a 3-story Waterfall. Behind it are elevators. Take these to the 'Sky lobby' (which is up 2 levels) and at the reception desk ask for IBM. You may need a security pass from the building security which will take a few minutes as they scan your picture ID and make a picture temporary badge from it for you. Everyone - BE SURE TO BRING A PICTURE ID IBMers - BE SURE TO BRING YOUR BADGE AND A PICTURE ID Then go right and the IBM office is on the left all on the same level. Here's a very low quality floorplan of the Copley Place Mall. Not sure it's helpful, but it's all I could find online. http://www.simon.com/mall/images/floorplans/784Copley_PlaceMall.gif

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Telcon notes 2005-9-21
by Martin Westhead 21 Sep '05

21 Sep '05

Present ======= Martin Westhead Tara Talbot Bob McGrath Geoff Judd Suman Kalia Items ===== Agenda for sessions/F2F at GGF ------------------------------ Is registration to GGF necessary? Probably not if you are only interested in DFDL then group members can probably skip the GGF altogether. 3 day meeting Monday, Tuesday, Wednesday: GGF meetings o Monday 1100 DFDL intro session (Park Plaza) o Monday 1400 DFDL discussion session (Park Plaza) Topics (Mike will arrange them) o Summary of approach (Mike) o Summary of issues on major topics (Topic holders) o Arrays (Bob) o Scoping (Mike) o Layers (Tara) o Null and Default (Geoff) o Properties discussion (Suman) o Process (documents and timescales) (Martin) o Conclusions and priorities o Issues List (remaining time) Note: This is a reasonable list of topics based primarily on the list of trackers at the start of the meeting (of which there were 4). During the meeting we added 6 new trackers. In light of this we may want to revisit this list of topics next week and consider the priority of the new items against the old. - Martin Tracking document modifications ------------------------------- "Edit required" status added to issues list to denote items that have been discussed but for which document edits are still outstanding. Issues list (starting from item 16) ----------------------------------- Resolved 16-27 (list has been updated). Start next week on item 28. New trackers: - Properties discussion (Mike, Suman) - Open content and wild cards (Geoff, Steve) - Choice and guards (Geoff) - Use statements (Mike) - Extensibility (Martin, Tara, Jim, Mike, Bob) - Expression language (Mike, Suman, Martin) N.B. we did not discuss priorities on the call. All these tracker items have been set to medium.

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Wednesday's telcon
by Martin Westhead 21 Sep '05

21 Sep '05

9am PDT Wednesday 21st September 2005 Preliminary Agenda ------------------ - Agenda for sessions/F2F at GGF - Tracking document modifications - Issues list (starting from item 16) Conference call instructions: Number: 1-800-664-0771 At the automated answering system, press 0 for the operator. Ask for the "Daffodil working group" call.

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minutes of call 2005-09-14
by Mike Beckerle 20 Sep '05

20 Sep '05

Who: Jim Myers, Mike Beckerle, Tara Talbott, Steve Hanson, Geoff Judd, Bob McGrath Agenda: GGF plans - we will have F2F at GGF15. The schedule of our WG sessions at the GGF15 are not yet set, but we'll have F2F meetings during the non-scheduled times. We're counting on the fact that most of our DFDL WG members are focused on DFDL and won't mind the conflict with the rest of GGF15 much. People should make travel plans for all 3 days M, T, W. GridForge Forums - these seem to be working now. Will try them when one of our subcommittees reports back to the broader WG. E.g., scoping or arrays. Issues list - we made it through items 5 to 15 Issue 5 - resolution. No built-in set of defaults. If you need a property and your configuration doesn't have one specified then it is an error. There is a small set of named configurations provided with DFDL each of which is a self-consistent set of properties. This is probably the set that we find useful in the primer and other WG docs. Issue 6 - resolution. change attribute name from 'base' to 'extends' Issue 7 - belongs on same tracker as 8, 9, 10 Issue 11 - resolution: add an attribute 'byteOrderMarkPolicy' values are: required, notAllowed, optionalButGenerateOnOutput, optionalButOmitOnOutput (the generate on output control aspect was not discussed on the call. I thought of that just now while typing.) Issue 12 - fix diagram - omission of these types was unintentional. Better diagram next draft Issue 13 and 14 - new tracker item - Steve Hanson, Geoff Judd and someone from MikeB's team at IBM to address Issue 15 - resolution: each delimiter will grow an extra rep-property for its regexp variant. E.g., separator will have corresponding separatorRegexp property. Only one of the two may be specified. We discussed that separator (or any delimiter) can be a text string, and we had previously decided that the separatorEncoding attribute would go away to be replaced by a syntax for expressing hex bytes (not hex character codes, real non-charset transformed hex bytes) as part of delimiter strng literals. This same way of putting hex bytes would also be supported as part of the regexp language so that the regexp language remains able to include any non-regular expression for a delimiter into a regular expression. (Editor's Note: this is a bit tricky. We now have in string literals 3 different escape mechanisms that are different. 1) XML character code specifiers e.g., 'abc,def' which is the normal XML way of specifying the unicode #x2C character code. (This is an XML standard escape convention.) Used inside a delimiter string this means take the unicode #x2c code point, figure out what character it corresponds to in the charset of the data element and use that character. Note that this is the same thing that 'a' means. Take the 'a' unicode code point, figure out what character corresponds to 'a' in the charset of the data element, and look for that. 2) nonXML character code specifiers e.g., 'abc\#x00;def' which is the way we allow you to put XML-disallowed unicode character codes like #x00 into a string literal. (This is a DFDL convention). The interpretation here is exactly like the above. I.e., '\#x2c;' is exactly equivalent to ',' and the charset mapping applies as above. This rule is only needed because of the XML restriction disallowing certain unicode character codes from the XML infoset. 3) non-character byte specifiers. E.g., 'abc\%01;\%02;def' which is a proposed escape syntax that means put the bytes #x01 and #x02 into the string literal bypassing any considerations of charset, i.e., without considering them to be character codes in any character set. That is, these byte values have nothing to do with unicode codepoint values. (This is a DFDL convention.) The other characters of the string would be treated as per (1) and/or (2) above. )

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Fw: [dfdl-wg] minutes of call 2005-09-14
by Steve Hanson 15 Sep '05

15 Sep '05

Hi Mike Re the three escape mechanisms. It is unfortunate that we need a separate mechanism for the second case (as discussed in the draft spec section 26). Re the third mechanism for escaping hex literals. An alternative syntax could be \#0x2C; using 0x to indicate hex. &#0x2C; would be even better - but does it cause XML problems? Regards, Steve ----- Forwarded by Steve Hanson/UK/IBM on 15/09/2005 09:33 ----- Mike Beckerle <beckerle(a)us.ibm. com> To Sent by: dfdl-wg(a)gridforum.org owner-dfdl-wg@ggf cc .org Subject [dfdl-wg] minutes of call 14/09/2005 22:18 2005-09-14 Who: Jim Myers, Mike Beckerle, Tara Talbott, Steve Hanson, Geoff Judd, Bob McGrath Agenda: GGF plans - we will have F2F at GGF15. The schedule of our WG sessions at the GGF15 are not yet set, but we'll have F2F meetings during the non-scheduled times. We're counting on the fact that most of our DFDL WG members are focused on DFDL and won't mind the conflict with the rest of GGF15 much. People should make travel plans for all 3 days M, T, W. GridForge Forums - these seem to be working now. Will try them when one of our subcommittees reports back to the broader WG. E.g., scoping or arrays. Issues list - we made it through items 5 to 15 Issue 5 - resolution. No built-in set of defaults. If you need a property and your configuration doesn't have one specified then it is an error. There is a small set of named configurations provided with DFDL each of which is a self-consistent set of properties. This is probably the set that we find useful in the primer and other WG docs. Issue 6 - resolution. change attribute name from 'base' to 'extends' Issue 7 - belongs on same tracker as 8, 9, 10 Issue 11 - resolution: add an attribute 'byteOrderMarkPolicy' values are: required, notAllowed, optionalButGenerateOnOutput, optionalButOmitOnOutput (the generate on output control aspect was not discussed on the call. I thought of that just now while typing.) Issue 12 - fix diagram - omission of these types was unintentional. Better diagram next draft Issue 13 and 14 - new tracker item - Steve Hanson, Geoff Judd and someone from MikeB's team at IBM to address Issue 15 - resolution: each delimiter will grow an extra rep-property for its regexp variant. E.g., separator will have corresponding separatorRegexp property. Only one of the two may be specified. We discussed that separator (or any delimiter) can be a text string, and we had previously decided that the separatorEncoding attribute would go away to be replaced by a syntax for expressing hex bytes (not hex character codes, real non-charset transformed hex bytes) as part of delimiter strng literals. This same way of putting hex bytes would also be supported as part of the regexp language so that the regexp language remains able to include any non-regular expression for a delimiter into a regular expression. (Editor's Note: this is a bit tricky. We now have in string literals 3 different escape mechanisms that are different. 1) XML character code specifiers e.g., 'abc,def' which is the normal XML way of specifying the unicode #x2C character code. (This is an XML standard escape convention.) Used inside a delimiter string this means take the unicode #x2c code point, figure out what character it corresponds to in the charset of the data element and use that character. Note that this is the same thing that 'a' means. Take the 'a' unicode code point, figure out what character corresponds to 'a' in the charset of the data element, and look for that. 2) nonXML character code specifiers e.g., 'abc\#x00;def' which is the way we allow you to put XML-disallowed unicode character codes like #x00 into a string literal. (This is a DFDL convention). The interpretation here is exactly like the above. I.e., '\#x2c;' is exactly equivalent to ',' and the charset mapping applies as above. This rule is only needed because of the XML restriction disallowing certain unicode character codes from the XML infoset. 3) non-character byte specifiers. E.g., 'abc\%01;\%02;def' which is a proposed escape syntax that means put the bytes #x01 and #x02 into the string literal bypassing any considerations of charset, i.e., without considering them to be character codes in any character set. That is, these byte values have nothing to do with unicode codepoint values. (This is a DFDL convention.) The other characters of the string would be treated as per (1) and/or (2) above. )

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Re: [dfdl-wg] Telcon Summary 2005-09-07
by Martin Westhead 08 Sep '05

08 Sep '05

> who are members of DFDL. To get membership you have to go to the DFDL > page and click on "Request membership" in the top right. Can Tara and > Bob, and anyone else who might lead a team do this please? I just double checked this. It turns out that tracker artifacts can only be assigned to site administrators. So, we could make everyone administrators, but for now, I have added a custom field "Team leader" which we can set the options for. Martin

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Issues list update
by Martin Westhead 07 Sep '05

07 Sep '05

Since the issues list seems to be useful. I have updated it after today's discussion. I have also tidied up a few formating glitches. Please let me know if there are any further problems (strange characters etc.) with the way it is displayed. I have added an Issues List Master document which is the Open Office version (.sxc) of this document. Unfortunately Gridforge adds a .unknown extension when you download it, this may need to be deleted to get open office to accept it. In future if you are constructing a list of comments for the group that you believe are likely to end up as issues it would be very helpful if you could arrange them in something close to this format. i.e. a table in some format (Excel, Word, HTML, Open Office, etc) with some of these columns. Then the relevant columns can be cut and pasted into place. Thanks, Martin

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Fw: [dfdl-wg] Opaque/BLOB/Uninterpreted/Raw - also hexBinary - (was Re: split into multiple topics - Re: [dfdl-wg] Issues: additional data types)
by Steve Hanson 07 Sep '05

07 Sep '05

I prefer the hexBinary approach. The disadvantage Mike observes with the array of bytes approach is not limited to conversion to XML. It would also apply to any in-memory tree (SDO etc) built by the DFDL parser. And the element unnecessarily becomes eligible to take the dfdl:occurs annotation. Regards, Steve Steve Hanson WebSphere Business Integration Brokers, IBM Hursley, England Internet: smh(a)uk.ibm.com Phone (+44)/(0) 1962-815848 ----- Forwarded by Steve Hanson/UK/IBM on 07/09/2005 11:23 ----- Mike Beckerle <beckerle(a)us.ibm. com> To Sent by: Mike Beckerle <beckerle(a)us.ibm.com> owner-dfdl-wg@ggf cc .org dfdl-wg(a)gridforum.org, "Robert E. McGrath" <mcgrath(a)ncsa.uiuc.edu>, owner-dfdl-wg(a)ggf.org 06/09/2005 21:21 Subject [dfdl-wg] Opaque/BLOB/Uninterpreted/Raw - also hexBinary - (was Re: split into multiple topics - Re: [dfdl-wg] Issues: additional data types) re: Opaque or uninterpreted or raw fields. These are sometimes called Blobs, though database people reserve that term for the acronym "BLOB" which stands for Binary Large Object, which has to do with size being too large for the smaller binary SQL type objects. I.e., there's no such thing as a small BLOB in databases. I think in our mailing list we've used blob to mean "opaque bytes" of any size at all. I believe use of the 'hexBinary' type is also probably this same topic. I.e., how to deal with data where you don't know its proper interpretation, though you can express how big it is so that we can at least copy it from place to place. I think there are two choices here. One is just use "occuring" bytes. E.g., here's uniterpreted data of length 1234 bytes: <element name="ignoreMe" type="byte" minOccurs="1234" maxOccurs="1234" dfdl:repType="binary"/> This is a basic binary byte array. I think this works fine as a blob/opaque type. I believe we do not need any other kind of raw/opaque type. If we had one, we'd have to have a way to express its length, and be specific about the units of that length, and the above accomplishes that with pretty much minimum baggage. You name it what you want, i.e, "unused" or "dummy" or "ignore" or whatever you want. We might want an annotation to indicate that this data should not be accessed, to distinguish this case from an actually array of bytes that you DO want to access, but I'm not sure that's worth it. Note that the OMG CAM model does have an access control attribute. Perhaps we can use that. However, I doubt it allows distinguishing copy from access. The alternative is to use the "hexBinary" type for this. In that case we need to express the size in the DFDL annotation: <element name="ignoreMe" type="hexBinary" dfdl:repLength="1234" dfdl:repType="binary"/> I can think of one advantage of hexBinary over the occuring bytes approach, which is suppose you do want to use DFDL in the obvious way to convert data into XML format. Never mind that DFDL is supposed to enable avoiding this, suppose it's what you want to do. Then my above byte array for the "ignoreMe" element ends up as: <ignoreMe>0</ignoreMe><ignoreMe>0</ignoreMe><ignoreMe>0</ignoreMe><ignoreMe>0</ignoreMe><ignoreMe>0</ignoreMe><ignoreMe>0</ignoreMe>....<ignoreMe>0</ignoreMe> Which is big compared to: <ignoreMe>000000000000...00</ignoreMe> which is what we'd get if we allow hexBinary as a type. Note that if we add the hexBinary type, you'll still be able to do it the other way, so the hexBinary notion is not strictly speaking necessary or minimalist. ...mikeb Mike Beckerle Architect, Scalable Computing IBM Software Group Information Integration Solutions Westborough, MA Mike Beckerle/Worcester/IBM@IBMUS Sent by: To owner-dfdl-wg(a)ggf.org "Robert E. McGrath" <mcgrath(a)ncsa.uiuc.edu> cc 09/02/2005 04:34 PM dfdl-wg(a)gridforum.org, owner-dfdl-wg(a)ggf.org Subject split into multiple topics - Re: [dfdl-wg] Issues: additional data types I'd like to split this topic into several distinct ones: Arrays - I have a placeholder for this in the doc. Opaque and "code" types are separate. This is related also to the concept of "open content". Enums Bitfields Pointers Mike Beckerle Architect, Scalable Computing IBM Software Group Information Integration Solutions Westborough, MA "Robert E. McGrath" <mcgrath(a)ncsa.uiuc.edu> Sent by: owner-dfdl-wg(a)ggf.org To dfdl-wg(a)gridforum.org 09/02/2005 03:13 PM cc Subject [dfdl-wg] Issues: additional data types Greetings, Here is an "issue" for the DFDL: additional data types that should be considered. Please see attached. --- Robert E. McGrath National Center for Supercomputing Applications University of Illinois, Urbana-Champaign Champaign, Illinois 61820 (217)-333-6549 mcgrath(a)ncsa.uiuc.edu (See attached file: DT.htm)

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