Paul Rubin wrote:
> Steven D'Aprano <[EMAIL PROTECTED]> writes:
>
>>But there is a difference: writing assembly is *hard*, which is why we
>>prefer not to do it. Are you suggesting that functional programming is
>>significantly easier to do than declarative?
>
>
> I think you mean imperative. Yes, there is a community that believes
> that writing bug-free programs in functional style is easier than
> writing them in imperative style. Writing buggy programs might be
> easier in imperative style, but in some application areas, that's not
> good enough.
>
> Why don't you read the Hughes paper I cited instead of taking cheap
> shots at it without reading it, if you want to understand the issues
> better.
Just some comments from my own experiences concerning bugs and writing
dependable software. It pretty much depends on a number of things and
isn't just a matter of good design or what language is used.
* The dependability of the hardware
* The dependability of the OS
* The stability of the language used
* The programmers knowledge of the language used
* Program design
* How many programmers are working on the same project
* How many extensions are used and written by other people
* The stability of those extensions
* Rate of change of the program design, and all underlying parts.
A small program with no external modules and written by a single person
can be fairly dependable, or as dependable as the underlying language,
OS, and hardware.
But as soon as the softwares complexity increases and/or multiple
programmers are used, either directly or indirectly through third party
extensions, then the probability of bugs increases substantially.
Given *enough* time, effort, and testing, without changing the design,
even a large program can be nearly as dependable as the least dependable
part of the platform it is running on. ("enough" could be a long time
here.)
To increase reliability to nearly 100%, you need to run different
versions of a program on several different platforms simultaneously and
use only the results that have a majority agreement.
Or to put it another way; risk management by ... "keep it simple",
"don't have too many cooks", "get second opinions", and "don't put all
your eggs in one basket".
Cheers,
Ron
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