Re: J4 - presentation/discussion on "Future of the COBOL Standard"



On Mon, 10 Mar 2008 09:20:46 -0600, Howard Brazee wrote:

On Mon, 10 Mar 2008 07:16:52 -0000, tim <TimJ@xxxxxxxxxxxx> wrote:

COBOL is not a good candidate for running on JVMs and .NET due to
technical problems ie use of redefine and pointers (which are in effect
arbitrary redefines), also packed decimal which is not well supported off
the mainframe. You can make it work, but it will run slowly.

Why does being able to use packed decimal make CoBOL a poor candidate?
If it doesn't fit in your environment, there's no requirement that it
has to be used.

If the program you are compiling says packed-decimal the standard says it
must be stored in packed decimal format. Of course you can provide
optimization flags that allow this rule to be overridden in the name
of speed. But with redefines and pointers/linkage it gets very difficult to
maintain correctness in the generated code if you change the format from
packed decimal to binary for example.

Packed decimal is mostly about the same speed as binary on IBM mainframes,
but it's a lot slower than binary on most Unix/PC CPUs. Packed decimal is
a lot faster than display format on mainframes for arithmetic, due to lack
of microcode support for most arithmetic operations performed on display
format data.

Tim
.



Relevant Pages

  • Re: J4 - presentation/discussion on "Future of the COBOL Standard"
    ... must be stored in packed decimal format. ... But with redefines and pointers/linkage it gets very difficult to ... Packed decimal is mostly about the same speed as binary on IBM mainframes, ... of microcode support for most arithmetic operations performed on display ...
    (comp.lang.cobol)
  • Re: Bit and Byte etc.
    ... And went with the dup of coffee you got while waiting ... It was used where mainframes used 'packed decimal' format for business ...
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  • Re: Cobol problem (INPUT File Format)
    ... > Pertaining to my earlier posting, ... Just a format only below. ... > - REDEFINES within a REDEFINES ... > use in the input file. ...
    (comp.lang.cobol)