Re: How to develop a random number generation device

On Sep 19, 3:38 am, MooseFET <kensm...@xxxxxxxxx> wrote:
On Sep 18, 7:05 am, Martin Brown <|||newspam...@xxxxxxxxxxxxxxxxxx>
wrote:

actually there. Walkthroughs and static analysis tools can find these
latent faults if budget permits.

Static analysis tools can only find some bugs. Some code has to be
stepped through to see if it ever gets stuck or goes into a loop. I'm
thinking of things like:

while (X > 1) do
if (X is even) X = X/2;
else X = 3 * X + 1;

It is really hard to see whether for some values of X this sticks in a
loop or not.

Halting problems are intrinsically hard. Nothing much you can do about
that.
So hard in fact that the hailstone numbers belong to the Collatz
conjecture and are expected to terminate eventually with the repeating
pattern 4 - 2 - 1 - 4 .... ad infinitum.

However no proof exists. And a brute force search out to around 2^58
failed to find any numbers that didn't.

business paradigm is ship it and be damned. You can always sell
upgrades later. Excel 2007 is a pretty good current example of a
product shipped way before it was ready. Even Excel MVPs won't defend
it.

I have always worked in an environment where bugs are not allowed. I
don't have a perfect record, but I'm sure that my rate of making bugs
is way lower than that of the average programmer in an environment
where bugs are allowed. Practice helps.

Depends what you are working on. If a failure can have mission
critical implications then people pay a lot more attention. If the
screen refresh gets garbled and a few icons go missing nobody really
cares.

Software programming hasn't really had the true transition to a hard
engineering discipline yet. There hasn't been enough standardisation
of reliable component software parts for sale off the shelf equivalent
in complexity to electronic ICs that really do what they say on the
tin and do it well.

... and further: In a lot of ways, we need better languages. Back in

Better languages already exist, but almost no-one uses them.

We needed a "get the next character from COM1 or any change in the
modem status in the order they happened please" function.

I like the idea of modules. Maybe we could have a programming system
that is more like designing analog hardware. You indicate where the
data goes, putting down the modules you need and wiring them up.

Already exists Nicklaus Wirth's minimalist language Modula-2 more or
less fits the bill. Small simple language with very tightly defined
module interface opaque types and low level generic IO primitives. It
never really caught on.
Logitech (now of mouse fame) sold commercial versions of the ETH
Zurich M2 compiler for PCs in the mid 80's.

http://www.modula2.org/
http://www.cfbsoftware.com/modula2/

Have some of the history. Ada tried to be everything to all men and
became bloated as a result.

Have you ever played with "artsbuilder". It is sort of what I'm
thinking of.

No. But I was once a fan of Nassi-Schniederman diagrams which
encapsulate program logic in a visual form. Sadly the graphical tools
of the day were not really up to it. Sceptics called them nasty
spiderman diagrams.

Regards,
Martin Brown

.

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