On Sat, 6 Oct 2012 09:07:31 -0400, John Gilmore wrote:
>Paul Gilmartin wrote:
>
><begin extract>
>And I still find it strange that RECFM=VB allows a logical record with
>data length of 0, but for RECFM=VBS, there is no way to construct a
>logical record with data length of 0.
><end extract>
>
>It is not that there is no way. I can think of one, and I suspect
>that you have thought of one, ...
>
Did I carelessly omit the word "valid" where I notionally
intended it. And let's skip any discussion of techniques.
The essence is I'm baffled. I can think of no valid
representation in a RECFM=VBS data set of a logical
record with zero data length. If I've missed something,
please enlighten me. I'd appreciate hex representations
if more understandable than English descriptions.
> ... It is that the tradition of FORTRAN
>green words for data-directed I/O---It dates back to tape I/O for
>Backus's first FORTRAN compiler for the IBM 704---is still strong and
>pervasive.
>
You flatter me. I had to look it up:
http://www.idinews.com/history/greenWords.html
Aftermath
The direct impact of resolving this conflict was that users all over
the world were able to pass files between programs written in
Fortran and programs written in other languages, without special
conversion utilities or messy interfaces.
Such unjustified optimism! So many utilities nowadays contain
the disclaimer that they don't support spanned records. If I had
been Emperor of the Universe, my second act would have been to
decree that all utilities shall support VBS[A]; support for additional
record formats would be optional. That could have spared many
cumbersome and divergent continuation conventions in Assembler,
JCL, TSO, IDCAMS, ...
For the ultimate irony, did the FORTRAN compiler source code
input with RECFM=VBS?
-- gil
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