Subject: Stephen Whitley (GECO-Prakla): comments on HPFF v0.1 document

From: [email-masked]
Date: Mon, 17 Aug 92 09:22:38 CDT

From: [email-masked] (Stephen Mark Whitley)
Subject: HPF I/O
Date: Fri, 14 Aug 92 11:21:13 CDT

Issues for

       High Performance Fortran
        Language Specification

Chapter 7  Input/Output

General...

    Having worked with a few machine specific formats before, I would
    recommend strongly against the inclusion of such a concept in a
    "portable language".  It is not enough to simply have the language
    portable to machines, the external representation data (at least
    layout) should also be portable.  

    The obvious exception would be in a situation where the cost of
    doing i/o is prohibitive. In such a situation, I would feel better
    with extensions (possibly vendor supplied) to the language to
    optimize the i/o at the cost of portability than to introduce the
    concept of non-portable external data representation within the scope
    of HPF.

Specifics...

7.1  

    >> the second proposal may affect the order the data items are
    >> stored within records.

     This sounds painful.  I want to share data between machines and
     between programs on the same machine that might operate with
     different alignments. 

    >> Both proposals require the following restriction on ...
    >> ... is legal Fortran HPF

     I understand the necessity of separating these operations,
     however, to maintain the greatest portability between F90 and HPF
     would it not be better to let the HPF compiler resolve the
     dependency internally?

7.2.4

    >> A new connection specifier of the form .....

     Is there any way a directive could be used to maintain the F90
     syntax.

7.2.6 

    >> new intrinsic of the form ...

     Not portable to F90.  (however, I must admit to liking this
     option)

7.3
 
   >> ...

    Sounds useful, however, it might be asking too much to force
    the use of external reformatters to produce a copy of the data
    that is usable by other applications.

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Stephen Whitley                             Houston, Tx 77077
GECO-PRAKLA                                 Office:  713-596-1511
[email-masked]                [email-masked]
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