🚀 go-pugleaf

nevin@apple.com (Nevin ":-]" Liber) writes:

>In article <TMB.92Nov19002135@arolla.idiap.ch>, tmb@arolla.idiap.ch (Thomas
>M. Breuel) wrote:

>> C's
>> lack (in fact, intolerance) of runtime typing and array bounds
>> checking, on the other hand, mean that hardware designers these days
>> seem to make little effort to support such features,

>I don't see anything wrong with getting rid of features that people aren't
>using.  If those features were popular, C probably wouldn't be as popular
>as it is today.  We have lots of CISC archetectures with cool features that
>very few people ever find useful.  Why waste the silicon?

Firstly, I agree that we should have very regular instruction set computers
(RISC). However, building bounds checking into silicon while being
something that is not essential is highly desirable. I make this comment
against the background that silicon (gallium arsenide) if you like is
getting cheaper and more powerful, whereas software development is getting
more complex, and very expensive.

Unfortunately these days, not many people have had experience developing
software for machines that have such inbuilt semantics checks. However, I
can assure you that it makes tracking down errors much easier, as the
program is terminated straight away, with a specific error in a specific
line of the program. Thus most bugs are found during development before
software is shipped to customers. So better quality software is produced.

That is why you would waste silicon. To get a bit philosophical, why do
we have computers anyway? The answer is because people are important.
They are more important than computers. So it is better to waste a computers
time than a persons time. The whole argument of processor efficiency comes
from the misguided philosophy that computers are more important than people.
It is true that in the past they were very expensive. But now they are cheap,
so why do we persist with this old assumption.

Having hardware that does not have bounds checking is rather like having
a car that has no brakes.

>It's simply a feedback loop.  I much prefer it to having hardware and
>software people totally oblivious to each other.

Close. I would not say "totally oblivious", but "mutually independent". This
does not happen by accident though, but by careful design. Unfortunately,
this C/hardware combination is making hardware and software "mutually
dependent", and we will pay the price for this mistake in the long term.
-- 
Ian Joyner  ACUS (Australian Centre for Unisys Software)    ian@syacus.acus.oz
"Where is the man with all the great directions?...You can't imagine it,
 how hard it is to grow, Can you imagine the order of the universe?" ABWH
Disclaimer:Opinions and comments are personal.