Re: substr bif question

I'll throw my two cents in here...

Not only was the CPYFRMIMPF change documented in the v5r3 Memo to
Users, but if you followed IBM's recommendations in the first place
and had CCSID properly set on the file (and system), then you weren't
affected by the by the change anyway!

I know this is a pet peeve of Rob's, but I'd hardly care it evidence
that IBM doesn't put a lot of effort into upward compatibility.

-Charles

On Tue, Sep 22, 2009 at 7:06 PM, Bruce Vining <bvining@xxxxxxxxxxxxxxx> wrote:

Having worked for many years in the Rochester lab I can safely say that
upward compatibility is very important to the i development group. However
there is in every release a Memo to Users whose function is to describe the
changes made in the system that could affect your programs or system
operations. So upward compatibility is not 100%, but the goal is to get as
close as reasonably possible.

I don't know off hand about the CPYTOIMPF reference but I do know there was
quite a bit of "hurt" back in V5R3 with a change to CPYFRMIMPF. CPYFRMIMPF
basically had a defect and unfortunately that defect was actually being used
by quite a few users (without their knowing that it was a defect). The
change, and the impact of the change, was in the V5R3 Memo to Users though
that didn't reduce the "hurt" much.

Along the same lines I still recall way back in S/38 days when a company
(fortunately not one of my accounts) back in St. Louis, where I was a SE at
the time, ran into a lot of "hurt". They had inadvertently been coding to a
COBOL data management defect in a large number of their applications. It was
clearly documented in the manuals that it should work like 'A' but they had
found the actual behavior to be 'B'. They liked 'B' and used it extensively.
Then someone reported the defect and in the next release the COBOL compiler
was corrected so that documented behavior 'A' was across the board. As I
said, a lot of "hurt" was experienced.

So upward compatibility is not guaranteed. Defects need to be
corrected.  And sometimes initial designs are just plain wrong in
retrospect, sometimes again requiring incompatible change. But I would put
the i upward compatibility record up against any other system.


On Tue, Sep 22, 2009 at 5:20 PM, Dennis Lovelady <iseries@xxxxxxxxxxxx>wrote:

Too little information.  Can you (will you) provide a little
more detail, please?

Nah.  Because someone will pick nits as to why it's
not just applicable and I'll just let this die and
get back to the technical.

Either IBM changed the way something worked or they did not.  Lacking
evidence to the contrary, I'll assume that they've been true to the
concept.

Regards,
Dennis Lovelady
--
"God bless the Holy Trinity"
       -- placard in a Dublin parade



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Bruce
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www.powercl.com
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