Re: "extract" command enhancement (subfiles and BIFs)

Jim Langston wrote:

> Incidentally, this "halving" technique is one I learned years ago in school 
>from a
> math teacher.  By using the halving technique, you can pick any number from 1
> to 100 within 7 "guesses",

<<snip>>

Jim,

I cut my teeth on this back in the ol' days of the S/3.  We had an application 
generator
that worked off an ordered sequential file.  The program generator would use 
the halving
technique for each and every reference it encountered.  The results were 
printed as it was
created and wouldn't even drive a 200lpm printer.

I added a startup routine that built an array of 8 elements, the first, last, 
and points
between.  This reduced the number of "halvings" in half and was printer bound.  
When I
took it to the IBM data center and ran it on a mod 15 it spewed code at about 
800LPM!

Now when you have 20 programmers lined up for compile time it rocked!

The good part is that you can double (exponentially) the file and only add one 
"halving"
per exponent.  If 7 tries works within 100 records, 8 tries works for 200, 9 
tries for
400, 10 tries for 800, 11 for 1600, 12 for 3200, etc.  The bigger the file, the 
greater
the gain.

BTW, this also can work for ordered arrays and one or two halvings to place a 
start index
will reduce LOKUP time.

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