RE: Efficiency vs effectiveness (WAS: Force EOF in a Subfile)

I know this was kicked around but,

....I tested this issue a few years ago on a smaller machine with a small user 
base and I could not determine a measurable difference in performance with a 
subfile of 2500 records....

This I can believe, because when talking about subfiles, I believe the
real I/O processes are in the operations that execute on the subfile
control record, not the subfile. Meaning the Reads and the Readc to the
subfile record are all done in memory.

My preference has evolved into a preference for reserving a hidden field
in the subfile to contain original values, and sometimes the entire
original record, because it makes it easier to (1) check to see if the
record is changed without worrying about SFLNXTCHG, (2) no database read
is necessary to refresh the subfile (I use F5 for this), (3) it's easier
to make a change like adding F19 and F20 key presses (or other) to go
"left" and "right", even if it's necessary to implement using two or
three different subfile formats, (4) easier to add in other values, (5)
easier to link this subfile record (such as an invoice header) with
records to pull up from another file (such as invoice detail lines), and
so on.

Disclaimer: I still mix and match. :-) And a technique for subfiles I
picked up on from (Kevin Vandever?) involves SFLPAG=SFLSIZ and using
data queues, which may even cost time for possible extra disk I/O, but
as a user I like it better.

Efficiency versus effectiveness: Accuracy and precision within
user-acceptable parameters are number one of course, which relates to
"effectiveness".

But efficiency should always be a consideration, and like Joe Pluta
said, it's always a number one concern for a company that sells
software. Staring at a screen is no fun even for us programmers!

This is *especially* true for interactive applications that involve a
customer waiting at a counter or on the phone. And if it's an
application served over the Web, you have to add all that time that you
can't do anything about. And even internally, sometimes the company LAN
slows down.

And if you don't have to worry about any of that, it's still a very good
habit to have. When it becomes a habit, you hardly notice the extra effort.

Very rarely do we get requisition specs that make response time a
priority, but in part that's because users don't realize how slow we can
make their computers work! :-)  They notice how a program is faster if
you make a good change, but more often how slow it is!

Just my 2c too...

--Alan