OGSA Teleconference - 2 November 2005
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* Participants

  Jay Unger (IBM)
  Jem Treadwell (HP)
  Ellen Stokes (IBM)
  Chris Smith (Platform)
  Andreas Savva (Fujitsu)
  Manuel Pereira (IBM)
  Steven Newhouse (OMII)
  Mark Morgan (UVa)
  Steve McGough (Imperial)
  Tom Maguire (EMC)
  Fred Maciel (Hitachi)
  Hiro Kishimoto (Fujitsu)
  Andrew Grimshaw (UVa)
  Dave Berry (NeSC)
  Michael Behrens (R2AD, LLC)

  Minutes: Andreas Savva

* October 26 minutes approved with no changes

* Information Model discussion

  - Postponed for next Wednesday
  - Action: Andrew to identify the attributes needed for BES container

* EMS Sequence review

  - Reviewed sequence diagram and text sent to the list
  http://www-unix.gridforum.org/mail_archive/ogsa-wg/2005/11/msg00003.html

    The diagram has not changed since the last review. There is
    additional text explaining the steps.

  - An open issue is the meaning of the 'abstract JSDL document'.
    - In the simplest case a document that does not specify a
      particular resource (host) for execution.
    - A more abstract case is that of specifyin only an application
      name and data (input, output) and leaving the rest to the
      system.
    - Taking the OS as an example, if the OS element is defined then
      only that specific OS can be used. If left undefined then any OS
      can be used. There is no in between choice with JSDL 1.0. The
      expectation is that JSDL should be combined with some other
      language to provide more flexible descriptions.
    - (WS-Agreement is one option but the assumption is that it is not
      used in this sequence. )

  - Other existing work on preferences or selection policy?
    - EGEE uses Condor classads (with EGEE extensions)
    - Globus (no, since no there is no scheduler)

  - Can the Policy document may be empty? Then would just get
    whichever resource the EPS considers good enough.

  - Job management is out of scope of this scenario
    - How about job termination? It was discussed last time and is out
      of scope at this stage.
    - But it is a good idea to add the simplest case of 'control'
      returning to JM at the end of the job.
    - Agreed that this should be a separate sequence diagram.

* Naming discussion

  - There was substantial confusion with the statements made at the
    last F2F.
  - Confirmed that the gist of the statement was: "In OGSA pointers
    are EPRs that may or may not be WS-Names."
  - The additional question is whether individuals WGs, because of the
    service specifications they are defining, can choose to require
    WS-Names (their reasons for doing so may vary).

  - Why does a service require EPR comparison? Does it fall in the
    category of "Nice but..."
    - One example is to distinguish EPRs for identity purposes.
    - And one common usage may be to enable additional functionality
      for monitoring, etc.

  - The expectation is that even if some OGSA services mint WS-Names
    and other OGSA services deal with them, those other OGSA services
    may also have to tolerate vanilla EPRs because there may be
    non-OGSA services in the system.

  - Does the requirement for WS-Names have to be part of the interface
    signature or is it more of a compliance statement that should be
    in a profile instead?

  - Is it an optimization? Can there be implemenations that
    functionally work without this feature, even if sub-optimally? So
    to make this feature mandatory becomes an overstatement.
    - It is also putting the onus on the client to manage the
      identities vs requiring the service to provide an operation.
    - Filesystem traversal as one(another) case where such an
      optimization (WS-Name) is useful.
    - The logging use case mentioned earlier is a commonly cited
      one. But in Jay's experience the identifiers have to be
      explicitly designed for the specific system and do not
      generalize.

  - Also the 'unique-in-space-and-time' statement is another point
    of disagreement.
    - To guarantee uniqueness there are two approaches: 1) arbitrator; or
      2) agreed upon algorithm (with some unique input) used by
         everyone.
    - Agreed that something closer to (2) is expected but it is more
      of a best-effort. So the space-time guarantee is not expected to
      hold literally.
  
  - Noone on the call doubts the usefulness of WS-Names in helping
    build quality implementations. The disagreement is whether they
    must be mandated in the interface signatures of basic specs.

  - The open issue is what is the statement OGSA should make to the
    fellow WGs. Is this issue something that can be left to each
    individual WG or should it be tackled by the Architecture (so
    within OGSA-WG).

  - Hiro proposed to write up a document defining the problem, what
    are the requirements and proposed approach; and circulate to
    interested parties. Continue discussion on the list and possibly
    re-review next week with Ian Foster and Frank Siebenlist.
    - Tom volunteered to start a draft

* UML Tool discussion - postponed