Re: Order

[bmorris@xxxxxxxxxx]

>From: "Dare" <oludare@ix.netcom.com>
>Date: Wed, 16 Jan 2002 13:11:35 -0500
>
>Way back in '95, I learnt that it is efficient and good for performance to
>have the most processed files in ascending order.  That is, if you're
>reading a master file and branching off using CHAIN or READ to fetch other
>information you should have your master file first in the F-SPEC.  Is this
>your understanding too.  If so, how do first open file relate to this
>concept of better performance programming.  Better performance programming
>meaning less burden on the system.

Dare, I've never heard that it's more efficient to have the most
processed files opened first.  If that IS true, you have to code
the most processed files at the bottom of the F specs.

Maybe the person who gave that tip didn't know that RPG opens files
in reverse order, and they were right about the order of _coding_
the F specs, and that it's actually better to open the most used
file last.  Or maybe this was true for some system or language,
and the idea has been passed along without regard to whether it's
valid or not.  Or, maybe it's true!  I don't know.

It might be a good idea to avoid opening the other file until you
know it's needed.

As to why the RPG compilers open the files in reverse order, it's a
compatibility issue now.  Originally, I imagine it was a programming
accident, where a developer built a linked list the easy way (add
new elements at the beginning of the list).

Barbara Morris