Re: Expected bytes per sloc (semicolons) performance

["Marin David Condic" <dont.bother.mcondic.auntie.spam@[acm.org>]

I think my point was that in many cases, prototype code and/or prior
experience with similar systems is a luxury that many, if not most projects
don't have. I've been on projects where we did have prior experience with
very similar systems and could quickly cobble together something that would
roughly approximate the new system and use that to gain some reasonably good
estimates of timing and sizing. Great if you can do that. What about when
you can't?

In software, we generally don't build the same thing more than once. While
there are systems with incremental improvements or spiral development
enhancements, those aren't typically the kind of things where the hardware
is being built from bottom dead center and desparately needs some kind of
information on what the software is going to require. When it is all brand
new is when you most desparately need quality estimates and this is
paradoxically when its hardest to make them. In both military and commercial
developments, this sort of situation arises often enough and there are a
variety of pressures that make it difficult or impossible to build a
prototype before you have to commit to hardware decisions.

Software development is not quite like most other sorts of engineering
development & it has a very hard time with measurement & prediction as a
result. Ask a civil engineer to estimate the design and construction time
for a building based on some sketches & dimensions and he stands a pretty
good chance of doing that pretty well because any one building is
sufficiently similar to others that you can base costs on the number of
square feet, etc. Us software guys don't get the same luxury because the
instant it becomes sufficiently similar to something done before, it gets
turned into a subprogram/subsystem with some parameters and the duplication
cost is pretty close to zero.

MDC

--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"Stephen Leake" <stephen.a.leake.1@gsfc.nasa.gov> wrote in message
news:ug09a0ykj.fsf@gsfc.nasa.gov...
>
> I did just that; get a similar processor or simulator, write some
> prototype code.
>
> Or, agree that you will only make evolutionary changes from the
> previous release. That's really the same thing; the previous release
> is a good prototype.
>