Minutes of a meeting held on 5th June 1978 at the Polytechnic of Central London,

309 Regent Street, London.


M. R. Lewis (Chairman)               Cray Research Inc

R. J. Collins                        UMRCC

C. Graff                             RAE Farnborough

G. L. Harding                        ECMRWF

A. P. Hayes                          UMRCC

D. Hill                              CCA

D. J. Holmes                         Rolls Royce Ltd, Bristol

G. L. Horsnell                       Imperial College

P. Loftus                            Marconi-Avionics (GEC)

J. D. Murchland                      University College, London

T. L. van Raalte                     AWRE

T. R. H. Sizer                       RAE Farnborough

F. Smithin                           RAE Farnborough

A. W. Stewart                        Honeywell Information Systems NISD

J. D. Wilson                         University of Leicester

J. M. Roberts-Jones (Secretary)      Liverpool City Council

Apologies for Absence:

P. A. Clarke                         Rothamsted Experimental Station

D. T. Muxworthy                      Edinburgh RCC

1. Approval of Minutes

The minutes of the meeting of 10th April 1978 were approved.

1A Officers

Mostyn Lewis announced that he was resigning as Chairman because of pressure

of work.

Alan Clarke was nominated to succeed as Chairman, and it being reported that he

had given his consent, the nomination was seconded and approved unanimously. A

It was further reported that Dr A. Colin Day was resigning from the steering

committee because of pressure of work.

The Secretary was asked to circulate an up-to-date list of the Officers of the

Group (See Appendix D).

2. Matters Arising from the Minutes

There were no matters arising.

3. Activities of Other Fortran Groups

The ANSI Board of Standards Review approved Fortran 77 as an American National

Standard on 3rd April 1978. The name "Fortran 77" is retained as an informal

designation, although the standard is in fact X3.9-1978. Final copy editing by

ANSI is under way; it is expected that publication will be in July or August.

4. Working Party Reports

No reports were available.

5. Other Recent Fortran Events

The BSI working group (BSI/DPS13/WG6), convened by David Muxworthy, is soliciting

comments on the next round of Fortran revision in preparation for the November ISO

meeting. The working group has requested this Group's co-operation in distribut-

ing a questionnaire (See Appendix B).

6. Retirement of Frank Engel Jr from X3J3

The Group noted with regret that Frank Engel Jr, who was Chairman of X3J3 from

1970 to 1977, had been expelled from the committee because of failure to meet the

stringent attendance requirements. It was resolved to record the Group's appre-

ciation of his contribution to the development of Fortran. John Murchland agreed

to draft the text (See Appendix A).

7. BCS'79

The Secretary was asked to circulate details (See Appendix C).

8. Other BCS Business

It having been reported that Pauline Halters had now left BCS Headquarters, it was

resolved to record the Group's appreciation of her assistance with our administra-


9. Any Other Business

Mr A. W. Stewart noted with astonishment a comment in the April 1978 issue of

Forward that "no known complete Fortran 77 compilers are available to date"; he

felt that the Honeywell compiler was one such.

Dr J. D. Murchland described various aspects of "pretty-printing" and drew

attention to a number of relevant papers in Sigplan Notices.

Mr D. Hill summarised the progress of the DOD Revised Ironman project, which has

now been refined to two (red and green) of the four Pascal-based candidate

languages. The status of Pebbleman in providing a working environment for Ironman

was also described.

There was an inconclusive discussion of various proposals for statement separators.

Dr J. D. Murchland presented arguments in favour of the adoption of "Fortran

Substandards", referring to Captain Grace Hopper's reported position on Cobol.

Mr G. L. Harding drew attention to a CDC internal document giving guidance on the

transition from current compilers to Fortran 77 compilers.

It was mentioned that various bodies were developing supersets of Fortran 77. The

US Department of Defense is specifying a DO-WHILE construct and various bit-

manipulation facilities. The US Department of Energy is considering asynchronous

transput and NAMELIST. A discussion ensued as to the desirability of strict

enforcement of standards. In this context, it was reported that because of the

stack-oriented nature of the ICL 2900 series architecture, problems could arise in

transferring programs which used non-standard techniques such as reliance on

argument retention which were not detected as illegal by earlier compilers.

10. Next Meeting

The date of the next meeting was agreed as 4th September 1978. However, it has

since been discovered that this conflicts with the BSC/DBAWG conference, and the

date has been changed to Monday 21st August 1978.

11. Talk on the Cray-1 Fortran Compiler

        Irene Q. Mallgrave gave a talk describing progress with the Fortran compiler

being developed for the Cray-1 processor.

        She first gave an overview of the hardware, describing the use of vector

registers to achieve parallel manipulation of up to sixty-four array elements

and explaining the concept of chaining, whereby an array expression of the form

(A op1 B) op2 C,

where op1 and op2 are binary operators corresponding to distinct functional units,

could be evaluated with overlapping of the two operations as well as of the

elements. The compiler is being developed by a team of six, one of whom is res-

ponsible for debugging aids. The main difference from a compiler for a more

conventional architecture arises from the loop analysis needed to detect loops

that can be replaced by vector operations.

        The overall design aim is to maximise hardware efficiency in executing

standard-conforming Fortran programs. A number of immediate goals are achieving

Fortran 77 conformance, scheduling vector operators to exploit chaining, improving

debugging tools (a cross-reference analysis has been implemented and the next step

is provision of a symbol table to the run-time support for use in post-mortem

analysis), and improving detection of vectorisable operations.

        The compiler is essentially two passes. The first pass performs parsing and

syntax analysis. It also deletes statement function definitions and expands

references in-line in order to improve vectorisability. The second pass identifies

"blocks" (a "block" appears to be a maximal sequence of graphically contiguous

executable statements the last of which is either an unconditional transfer of

control or a labelled statement), performs a vector analysis of each block (which

appears to correspond to loop detection, motion of loop-invariant code and a

process similar to strength reduction replacing loops of scalar operations by

vector operations) and generates intermediate code which is transformed by

scheduling for chaining and by a register assignment analysis.

A description was given of the way in which source programs could be trans-

formed in order to improve detection of vectorisable loops.

[No appendices are available for digitization. Following on from Appendix A,
Frank Engel Jr was awarded honorary membership of the BCS in a ceremony in London
in December 1978. The questionnaire in Appendix B is part of the BSI submission
to the ISO Fortran Experts meeting which is appended to the February 1979 minutes.
Appendix D would have been similar to the contact details for officers for the
following year which are attached to the April 1979 minutes.]