Productivity and error rates for Ada projects

[Michael J Zehr]

In article <8221 at hubcap.clemson.edu> wtwolfe at hubcap.clemson.edu (Bill Wolfe) writes:
>   From the November 1988 issue of IEEE Software, page 89 ("Large 
>   Ada Projects Show Productivity Gains"): 
>   [ada productivity higher and error rate lower than for C]
>
>   Does anyone know of any empirical results regarding the level of
>   productivity and defect rate associated with C-language projects?
>
>   It would be interesting to compare them to the results cited above.
>
>   Bill Wolfe, wtwolfe at hubcap.clemson.edu

One of the projects i've worked on is a hybrid of C and a 4GL called
Stratagem (sold by Computer Associates).  We don't have hard numbers of
productivity or errors, but i have a few observations.

1. Beyond a shadow of a doubt, productivity (measured in debugged code
modules) is much higher for the 4GL part than the C part.  Errors are
less common, and tend to be easier to find (this might in part be due to
more people having better training in the 4GL language than in C,
though).

2. If we had done the entire project in Stratagem, it would have been
finished much earlier, and there would have been fewer bugs.  And it
would have been totally useless for our client!

There is simply no way we could get the kind of speed we needed from the
program without resorting to C (or some other low-level language. note
however that there was really no quesion about which language we had to
use to go with Stratgem, however).

Sometimes you need to use a low level language to do a job efficiently
at run-time.  Our company policy has always been to use the highest
level language that will yeild acceptable run-time performance.  We use
C only when we have to.

[On a related issue, i noticed a much greater correlation between the
errors and the original coder than i did between errors and the language
being used.  And for a while i was doing most of the error-finding and
debugging for theproject....]

Comparing Ada and C as programming languages is much like comparing
buses and cars as transportation.  They are each good for some things
and bad for some things.

-michael j zehr