Re: Expected bytes per sloc (semicolons) performance

[Stephen Leake <stephen.a.leake.1@gsfc.nasa.gov>]

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

> <snip>
> 
> It does raise an interesting problem. If you have to commit to certain
> parameters early on in the project (such as memory or processor speed) how
> do you estimate how much you'll need when you don't have the software yet?

Exactly. Pretending this problem doesn't exist is _not_ an acceptable
solution. 

> Even assuming you've got prior experience with similar systems, you
> really have no good basis in measurement to make estimates until
> there is some actual software available. Maybe this suggests that
> software development should start way in advance of hardware
> decisions. 

Exactly. That's what "phase A"/prototypes are for. You can't commit
significant resources to a project until you know what you are doing.

> But that has its own problems with respect to time-to-market and
> other considerations.

Well, building satellites for NASA is certainly different than getting
out the next cell phone. But I think the same principles apply; you
have to experiment and prototype before you commit the final design. 

> Everyone can criticize just about any attempt to make measurements
> and estimates for lots of good reasons. Who could suggest a better
> alternative for how to make these estimates early on in a project
> when critical decisions must be made?

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.

-- 
-- Stephe