2MASS Working Group Minutes, #53

IPAC 2MASS Working Group Meeting #53 Minutes, 1/31/95


C.Beichman, T.Conrow, R.Cutri, T.Evans, J.Fowler, L.Fullmer, T.Jarrett, D.Kirkpatrick, G.Kopan, B.Light, C.Lonsdale, H.McCallon, S.Wheelock, J.White


  1. EXEC and PCP Subsystem Design
  2. Results of the January 27-28 Review
  3. Action Item Templates
(Note: the working group met several times since the last minutes were distributed, but the purpose of those meetings was to prepare for the January 27-28 review, for which proceedings will be published separately; the meeting numbers will increment only for meetings for which the publishing of minutes is appropriate.)


  1. EXEC and PCP Subsystem Design -- The 2MAPPS design includes modularization of science/engineering functions. The purpose for this is to allow the various cognizant engineers to focus as sharply as possible (hence narrowly) on their relative tasks with minimal drain of their resources into areas outside of their subsystems. Any avoidable dilution of effort would seriously threaten the goal of staying on schedule with the already optimistic timetable that we wish to compress as much as possible.

    It was for this modularization purpose that the EXEC and PCP subsystems were created. To the extent possible, these subsystems are meant to orchestrate the other subsystems while shielding them from arcane considerations that arise in the design of distributed processing systems. Early investigations into methods for implementing the EXEC and PCP subsystems led (among other areas) to consideration of "perl", a scripting language with extensions that might facilitate subsystem communication over a multiple-machine configuration. The study of perl was undertaken by T. Conrow and J. White. The study involved familiarization and exploration.

    After several weeks of study, the rate of progress in mastering perl left room for concern about whether this approach would bear fruit on the time scale needed, and so some priority was given to discussing the work done so far, future plans, and possible alternatives. T. Conrow reported on the particular aspects of perl that could be useful for 2MAPPS and described experiments currently underway. The potentially useful aspects of perl involve the distributed-system communication capability (which could enhance the effectiveness of the MONITOR function of EXEC, as well as provide a mechanism for launching tasks on multiple machines) and a convenient way (once set up) for subsystem development to toggle between a subsystem test environment and a system test environment. On the other hand, it was found by both investigators that perl is something of an opaque and alien language, raising fears about its maintainability.

    Since J. White (the cognizant engineer of the EXEC and PCP subsystems) is currently scheduled to be working on the TAPELOAD subsystem, and since T. Conrow is available to 2MASS at a significant level for the next year or so (but not available to assume cognizant engineer responsibilities), it was decided that T. Conrow will attempt over the next two or three weeks to develop a perl demonstration script that performs the functions needed by 2MAPPS, and if this can be done, we will continue to base the EXEC and PCP design (primarily PCP) on perl. The design and implementation would be done primarily by T. Conrow and delivered to J. White, accompanied by a thorough tutorial. The demonstration script would launch and communicate with at least two dummy subsystems running on at least two different machines. The dummy subsystems would need to demonstrate that they had received their command-line parameters successfully. The demonstration activity will not preclude investigating other possible avenues to achieving the functional capabilities needed.

  2. Results of the January 27-28 Review -- C. Beichman reported on the results of the January 27-28 review. The committee members were unanimous in being pleased with the progress that has been made and expressed confidence in IPAC's capability to accomplish the tasks set forth. The action-item burden from this review is quite a bit less than that from the previous review. While not very different in number, the items are generally better focused and individually simpler. C. Lonsdale will coordinate the assignment and tracking of these items. There is great optimism regarding the quality of the plans for the April protocamera observations, whose results should provide a wealth of information to aid in finalizing certain aspects of the 2MAPPS design. The analysis of the April data is not expected to produce significant obstacles to the development schedules, and as much as possible will be done by team members without subsystem development responsibilities. Among other surprise announcements at the review was the expectation that survey hardware acquisition may be accelerated to an extent such that the beginning of the survey may occur ahead of schedule by something on the order of a year (hence the desire to compress the 2MAPPS schedule).

  3. Action Item Templates -- Action items closed by presentations at the January 27-28 review are to be written up within about a week and submitted for inclusion in material accessible via the World Wide Web. This involves using LATeX, which can be converted directly into HTML for Web usage, as well as nicely formatted hardcopy via standard postscript. T. Evans has provide LATeX templates for this purpose; they may be found in /proj/2mass/doc/latex. Postscript images may be included via directives in the templates, although there remains some lack of flexibility in sizing, orientation, and text embedding (so far, images are coming out on separate pages and not necessarily filling the page). These limitations may be overcome in the near future, but in the meantime, they are not serious enough to justify any significant expenditure of time to work around.