Re: Reserve Demobilization System Built Around Re

[rharwood@east.pima.edu]

In article <1991Jun15.010746.12768@netcom.COM>, jls@netcom.COM (Jim Showalter)
writes:

>>My Personal Opinion:  Calling a DBMS or GUI or math routine is NOT reuse. 
>>Libraries of complex mathematical subroutines have been available to FORTRAN
>>programmers since ENIAC, I suppose.
> 
> What is it, then? "use-again"? "repeated-use"? "use-more-than-once"? Sounds
> like reuse to me...

COTS (commercial off-the-shelf) software could indeed be defined as "software
reuse".  And if that's the case, then everyone who's ever purchased
WordPerfect (<=insert the name of whatever word processor you like) instead of
WRITING THEIR OWN word processor has indeed REUSED software.

I guess what I'm proposing is that software REUTILIZATION be broken into three
distinct categories, with words and definitions similar to the following:

(1) Commercial Off-the-shelf (COTS) software:  executable machine instructions
written, compiled, and distributed by an organization as a primary market item. 
Includes word processors, spreadsheets, desktop publishing, and run-time-only
DBMS licenses, and I suppose also includes operating systems.

(2) Library routines: object code provided by someone other than the
end-product programming organization, generally without source code,
incorporated into a distinctly separate software "entity" with a purpose
greater than that of any individual library routine.  Includes mathematical
function libraries, matrix manipulation, file handling (such as an indexed file
system for PCs which have no inherent indexed file capability), DBMSs with
callable interfaces, network interfaces (like APIs?), and specialized "glue
routines" in one language designed to interface to the underlying operating
system or other COTS software.

(3) Reused/reusable Source Code: 3rd or 4th generation source language
statements provided by anyone (including within and outside of the end-product
programming organization) which is compiler by the programming staff and used
with little or no modification.  If you've got to run it through your own
compiler to use it, and you didn't write it, it's reused.

Summary:  COTS = executable, Libraries = object, Reuse = source.

Again, these terms & definitions are just my impressions of what many people
seem to mean when they talk about "not writing it yourself."  I suppose this
discussion is a lot like "recycling", a lot depends on your definitions! 
Driving alone in your own car every day ISN'T recycling dinosaur energy...

> Over multiple project lifetimes, mechanisms that keep coming up (that "haven't
> we built this already?" feeling of deja vu) eventually get turned into highly
> reusable componentry--such as a DBMS, a GUI, or a set of math routines did at
> some point in the distant (or not so distant) past.

Without belaboring the origins of any one DBMS, I'd say "Yes, Oracle (<=insert
name of any DBMS) was AT SOME POINT IN ITS DEVELOPMENT composed of reuseable
source code, but once it was compiled into an executable module and sold "as
is", then it became COTS software; and the linkable calls are a part of your
library of routines; but it's NOTp
suit your particular needs."

Indeed, Oracle Corp REUSED it's own code when porting the SOURCE code to create
executables for other platforms... but YOU can't take your own "reusable" copy
of Oracle and modify it to run on a 2MB Nintendo (without losing a LOT in the
translation!).

Ray