ISO/IEC JTC1/SC22/WG5 N853 S L A C M E M O R A N D U M November 25, 1992 ---------------------------- To: Interested FORTRAN users From: L. Moss Subject: Trip Report on X3J3 meeting, 9 - 13 Nov, 1992 ----------------------------------------------------------------- Note: This is a personal report of these meetings and in no sense does it constitute an official record. X3J3 met in New Haven, Connecticut from 9 through 13 November 1992. The US TAG (Technical Advisory Group) for Fortran (which consists of those US members of X3J3 who elect to pay the new "International Participation Fee") met on the afternoon of 11 November, and then again on 13 November. This report is confined to the X3J3 meeting; I will report on the US TAG meeting separately. FORTRAN 90 MAINTENANCE ---------------------- The principal goal for this meeting was to prepare responses to as many Fortran 90 defect reports as possible. Following the meeting, first X3J3 and then WG5 will conduct letter ballots to approve the responses for submission as official technical corrigenda to Fortran 90. The preliminary tally, based on partial results from the X3J3 letter ballot immediately preceding this meeting, was as follows: Responses ready for WG5 ballot -- 35 Responses ready for X3J3 ballot -- 44 Responses still in consideration -- 36 The request for interpretation in 92-202r raised an issue of strategy for improving the understandability of the standard. This paper pointed out a number of inconsistencies in the use of the terms "attributes", "properties", and "characteristics", and proposed a set of about 40, mostly minor, edits to fix the problem. A number of members felt that attacking such problems via the technical corrigenda process was not an efficient use of committee resources. Instead, they felt that the corrigenda should provide minimal fixes for specific problems, and more complete rewrites should be deferred to the 1995-96 revision. After some discussion, the full committee took a straw vote on this specific proposal; the result was not conclusive, but favored pursuing the approach outlined in 92-202r: SV (11-8*-5). Subsequently, members of the DATA subgroup worked on this proposal and came up with some suggested changes and additions but these have not yet been reviewed either by the subgroup or by the full committee (see 92-307 and 92-305; the latter also identifies the items in S20.122 -- 6 out of a total of 68 -- which would need edits to be brought into line with 92-202r). A couple of minor changes were made to our maintenance procedures. The committee voted unanimously that the item numbers in the maintenance document (formerly X3J3 Standing Document 20 or "S20", shortly to become 93-006) should never be reassigned. In addition, several members requested that we cease tracking open maintenance items via secondary "Unresolved Issue" numbers, and instead always use their "S20" (or "006", I suppose) numbers. The chair ruled in favor of this request. REVIEW OF HIGH PERFORMANCE FORTRAN ---------------------------------- A secondary goal of this meeting was to review the draft specification for High Performance Fortran (HPF) which is rapidly nearing completion. HPF is being developed by a group called the HPF Forum (HPFF) as an industry standard for massively parallel machines with distributed memory architectures. It is complementary to the parallel computing work being done by X3H5, which is independent of memory or data layout issues, and instead concentrates on block-structured parallel control structures. HPF is based on a subset of Fortran 90, with a number of directives to control the way data is laid out in memory. The directives are in the form of comments and can simply be ignored by a non-HPF compiler without changing the meaning of the program. However, the latest draft now includes one feature which goes beyond Fortran 90, namely, a FORALL statement. Despite this incompatibility, the sense of X3J3 was that FORALL was a useful extension for parallel machines. In a straw vote, the committee also reaffirmed its previous endorsement of the directives approach for data layout. HPF also includes a number of new functions, and there was some discussion of how the names of these functions should be managed. Normally, X3J3 would recommend putting all these functions into a MODULE in order to confine potential name clashes to those scoping units where the functions are actually needed. However, a few of these functions must be permitted in initialization and specification expressions, which implies that they need to be resolved like intrinsic, rather than module, procedures. The committee seemed to be generally agreed that HPFF should minimize the pollution of the intrinsic function name space, but was divided on how to do so. Some members felt that, since the module containing the new functions would be an "intrinsic" component of any HPF compiler (and because there was no expectation that the functions it contained would be written in Fortran), the USE for this module could act as a compiler switch to control the visibility of the new intrinsics. Others, however, felt that such selectively visible intrinsic functions were not included in Fortran's blanket permission to add implementation-specific intrinsics (p 2, ll 33-35), and so would constitute a second (along with FORALL) extension to Fortran 90. It was agreed that, following the meeting, the subgroup would draft a letter summarizing the views of X3J3, circulate the draft to the committee for a final round of comments, then send the letter to HPFF in time for their December meeting. COMMITTEE REORGANIZATION ------------------------ Following the last meeting, the chair proposed (in 92-181) reorganizing the committee into a new set of subgroups, so that about half the members would continue to concentrate on interpretation processing while the remainder would begin work on other tasks, including the 1995-96 minor revision and liaison with other standards bodies. Because of the large volume of new interpretation requests submitted between meetings, the committee agreed to continue for this meeting under its old subgroup structure. However, the reorganization plan was discussed by the committee and accepted with two modifications: one additional subgroup will be added to research object-orientation issues for Fortran (this subgroup will be named X3J3/OOF); and, for the next couple of meetings, subgroup time will be scheduled in such a way as to permit most members to serve on both the new X3J3/F90maint subgroup and on one of the other new subgroups. It is also expected that, for a time at least, X3J3/F90maint will continue to subdivide itself along the same lines as the old subgroups. Thus, at the next meeting, the committee will be organized something like this: Track 1 Track 2 ------- ------- X3J3/F90maint: X3J3/JOD General Concepts X3J3/OOF Data Concepts X3J3/parallel Control Constructs X3J3/posix and Input/Output Procedures and Program Units Track 3 ------- X3J3/editorial (The editorial subgroup will probably meet in parallel with both the other sets of subgroups.) The new subgroups did meet briefly one afternoon to get organized. Following the meeting (and the completion of some homework left over from the meeting) I resigned as chair of the old Data Concepts subgroup (or, if you prefer, the new /F90maint/Data Concepts subsubgroup ;-) in order to devote more time to chairing X3J3/JOD. X3J3/JOD is responsible for a new standing document (93-007) which is currently called the Journal Of Development. This document is also intended to be X3J3's "database of requirements" for future revisions of Fortran. ADMINISTRATIVE BUSINESS ----------------------- MEMBERSHIP At the beginning of this meeting X3J3 had 31 members, giving a quorum of 11 (=1+INT(Members/3)), and a majority of the membership of 16 (=1+INT(Members/2)). At the end of the meeting, no members had been lost but two were in jeopardy of being dropped for non-attendance. The poor (preliminary) response on the recent letter ballot prompted this reminder from the chair: X3 rules require that a member who fails to respond to three successive letter ballots must be dropped from the committee. FUTURE MEETINGS: 124th 8-12 February 1993, Fort Lauderdale, FL (host: Bill Leonard). 125th 10-14 May 1993, University of Illinois at Urbana/Champaign, IL (host: Kurt Hirchert). 1993 WG5 Meeting 5-9 July 1993, Berchtesgaden, Germany (host: Karl-Heinz Rotthauser). 126th 12-16 July 1993, Brussels, Belgium (host: Dick Hendrickson). 127th 8-12 November 1993, Albuquerque, NM. 128th February 1994, Sunnyvale, CA. NEXT DISTRIBUTION The closing date for the next pre-meeting distribution is 4 January 1993. To get an item into the distribution it should be received before this date by: Linda O'Gara Supercomputer Systems, Inc. 2021 Las Positas Ct. Livermore, CA 94550 Phone: 510-373-8040 FAX: 510-373-6270 Email: uunet!ssi!ljo