Path: utzoo!attcan!utgpu!radio.astro!helios.physics!sysruth
From: sysruth@helios.physics.utoronto.ca (Ruth Milner)
Newsgroups: comp.lang.fortran
Subject: Re: need advice porting program from VMS to Sun3
Keywords: fortran, Sun workstation
Message-ID: <1989Sep26.210148.7903@helios.physics.utoronto.ca>
Date: 26 Sep 89 21:01:48 GMT
References: <3542@sbcs.sunysb.edu> <2711@ccncsu.ColoState.EDU>
Reply-To: sysruth@helios.physics.utoronto.ca (Ruth Milner)
Organization: University of Toronto Physics/Astronomy/CITA
Lines: 39

In article <2711@ccncsu.ColoState.EDU> thorson@typhoon.typhoon.atmos.colostate.edu (Bill Thorson) writes:
>In article <3542@sbcs.sunysb.edu> cchen@sbcs.sunysb.edu (Chyouhwa Chen) writes:
>
>>I just ordered a 100K lines program written in VMS fortran for my
>>research.  I would like to port it to the Sun3 environment.
>
>I thought all Sun's had basically the same FORTRAN compilers.  Our Sun's
>FORTRAN came with a translator for VMS FORTRAN.  The translator is called
>f77cvt.  The way our compiler works is that if the file name ends with
>.vf or .for it is assumed to be VMS FORTRAN and if run throught the
>translator.

You should be aware that not all VMS extensions are supported. For example,
a lot of the OPEN options are not supported under UNIX because they relate
to record structure, which UNIX basically has no concept of. And, of course,
if your 100K-line package has any system calls in it, you will have to either
replace those calls with corresponding UNIX versions (if there are any) or
write your own routines.

Also, a number of simple VMS extensions were built right into f77 itself;
things like END DO and DO WHILE etc. If the Fortran is not heavily
VMS-dependent, you may be able to compile with just this. If you don't
need it, don't run f77cvt. Although it handles many of the other things
which were too big to write into f77, it has also been known to make some
unnecessary changes. I don't know about Fortran 1.2, but under 1.0 it
would, for example, do things like change quoted character strings in WRITE 
statements into Hollerith (ack). Neither necessary nor desirable. 

If your package was written for VMS, it is likely to be very difficult
to port. In my experience, vendors writing specifically for VMS Fortran
tend to make heavy use of its extensions, particularly in file formats.
If it is essentially mathematical in nature, though, you may be able to
get away with it since standard Fortran 77 covers what is generally
needed.
-- 
 Ruth Milner          UUCP - {uunet,pyramid}!utai!helios.physics!sysruth
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