From: Configuration Control Board

Table of Contents

  1. CCB Meeting 3 September 2008
    1. Attendees
    2. Proposals Discussed
    3. Meeting
      1. Open Source License
      2. Pixel Coordinate System
      3. Pure Image API
      4. Image Metadata
    4. From-the-Floor Items
      1. Approved Boost Libraries
    5. Status of Past Action Items
    6. New Action Items

CCB Meeting 3 September 2008

Attendees

Robyn Allsman
Roc Cutri
Robert Lupton
Russell Owen
Kian-Tat Lim
Jeff Kantor
Ray Plante (at start)

Proposals Discussed

Meeting

Open Source License

Ray reviewed the Open Source Licenses (or lack thereof) under consideration: GPL, Apache2, modified BSD, dual licenses, and public domain.

Since we currently use FFTW (GPL v?), the linked LSST codebase would devolve to GPL. Supporting GPL implies that commercial vendors will be inhibited from using LSST software until they de-couple all GPL library access.

  • should we alter our initial Open Source License search goals to remove direct commercialization of LSST software?
    • Jeff said commercialization was neither mandated nor a primary requirement; as a nicety, it can be set aside.
  • should we restrict the use of 'best' libraries because they use a GPL 2 license?
    • resolution: use best library for the job. If commercialization is inhibited, the vendor can remove the dependency.

Python READLINE has an alternate library, which is not GPL, to get around this licensing issue.

Robert sent email to fftw asking about their license particulars.

Options discussed:

  • Straight GPL license - not good for commercialization however LSST wouldn't take on a licensing enforcement role.
  • dual license - choose non-GPL for source (either BSD or APACH2); default to GPL for binaries.
  • public domain - no licensing at all for source; default to GPL for binaries.

Ray will prepare a proposal which outlines the best options, circulate to CCB members (ED: and others) for approval, and finally forward to the Board our considered opinion on the best selection. Jeff Kantor will have the options reviewed by a lawyer, if he feels its necessary.

Pixel Coordinate System

Deferred until Tim can join the discussion.

Pure Image API

Robert lead the discussion. The proposal is limited to an API to a pure Image (without metadata or WCS); explicitly does not include an interface to a Decorated Image (with metadata). In the past, software made direct calls to VW. The initial proposal was to move the use of VW behind a wrapper interface. This effectively converted VW to be an implementation detail once the wrapper was implemented.

Robert used the GIL image access library as a model for the pure Image API. GIL is a well respected and peer reviewed library interface. In fact, Robert has written the pure Image interface using GIL as the back-end. Robert's review of the iterators indicated that all required iterators were handled.

In light of the fact that he has already implemented the interface using the GIL back-end, he respectfully requested the CCB additionally approve:

  • the removal of VW from the approved software set;
  • the addition of boost:gil and boost:lambda.

Present CCB members were in agreement; Chair will poll the missing members (Tim and Ray) before approving proposal and adendums.

Image Metadata

KT presented the thrice revised Image Metadata Proposal which had a secondary review amongst the developers the previous week. Tim's issue concerning the difficulty of elevating the status of a metadata attribute from second tier to first tier were reviewed and addressed. It is true that elevating an attribute will necessitate a new formatter, a new DB field, and a recompile of any code accessing the new entity. KT suggested a workaround which would hide the change from most developers but would result in an overall slow-down for all attribute retrieval.

Tim's questions and issues are discussed in the Proposal.

All CCB members present were in agreement; Chair will poll the missing members (Tim and Ray) before approving proposal.

From-the-Floor Items

Robert suggests that Chair review all the past action items to determine if they have been completed. To that end, all past action items are listed below with their status. As items are completed, they will be removed from the list.

Robert pointed out that enforcement of past CCB approvals is not being done when it involves revising existing code.

After the meeting, Chair considered the issue and decided that agreements to alter coding style will be enforced more rigorously once the Coding Standards Checker is selected, installed, finally used during Release builds.

Approved Boost Libraries

Robert pointed out that the twiki page enumerating approved boost libraries is woefully out-of-date. He will update the page with comments about each library's use and whether it should be approved or removed from use.

Status of Past Action Items

Henceforth The CCB will track resolutions until they have been fulfilled. See: CCB Action Items.

New Action Items

  • Ray will update the Open Source License to present the CCB recommendation to the Board for Open Source Licensing; it will be reviewed by the CCB prior to referal to the LSST Board.
  • Robert will report on FFTW licensing status.:
  • Robert will complete the implementation of the pure Image API based on boost GIL and lambda (if Proposal approved).
  • Applications developers will design and implement the new Decorated Image (if Proposal approved).
  • Robyn will review the outstanding Past Action Items during each meeting to ensure progress.
  • Robyn will ensure that Ray and Tim agree to following proposals since they were unable to attand complete meeting.
    • Image Metadata proposal
    • Pure Image API proposal
  • Robert will update the list of LSST-approved boost libraries.