Typically, in C programming at least if you use
the C library rand function, it will only
return 'pseudo' random data. Meaning if you
run it each time the resulsts are the same.
So you must 'seed' the random number generator
with a seed to generate unique random numbers.
How 'random' your seed is, determines how
random and predictable your data. Most applications
suffice with just using the current time.
However, when dealing with security related
algorithms and such some more hardcore methods
are needed.
For a very nifty approach to generate check out
http://lavarand.sgi.com
The basic idea is take a few (six) lavalamps and snap
a picture of them. The image should always be
very random :)
Some math folks who were seriosuly into math analyzed
the outputs and determined this is one of the most
'random' or best ways to seed random numbers or generate
random data.
The guys who designed this have some real high level math
degree's and worked at SGI and basically got
bored one night... anyhow that was rather off topic
but its cool :)
Jeremy Allen
[EMAIL PROTECTED]
-----Original Message-----
From: Mark Warrick [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, September 20, 2000 7:15 AM
To: [EMAIL PROTECTED]
Subject: RE: [CF-Talk] Random Images-Resources for Information?
Curious. What do you mean by seed?
--------------------------------------------------------------
Mark Warrick
Phone: (714) 547-5386
Efax.com Fax: (801) 730-7289
Personal Email: [EMAIL PROTECTED]
Personal URL: http://www.warrick.net
Business Email: [EMAIL PROTECTED]
Business URL: http://www.fusioneers.com
ICQ: 346566
--------------------------------------------------------------
> -----Original Message-----
> From: Jim McAtee [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, September 20, 2000 3:01 AM
> To: [EMAIL PROTECTED]
> Subject: Re: [CF-Talk] Random Images-Resources for Information?
>
>
> Depends what you're thinking when you say random. If you mean calling
> the function 7 times always pulls up 7 different numbers, then that is
> NOT a random sequence. By chance (err... 'randomness') you could
> conceivably pull up the same number 7 times in a row (or a hundred times
> in a row). You'd sit there and say "This isn't random", but it's just a
> 'streak' of good/bad/neither luck that this strange sequence ocurred.
>
> One other thing, mostly unrelated to the above. The way computers
> usually generate random numbers is by pulling numbers out of a large,
> stored table (containing, you guessed it, random numbers). You should
> always seed the random number generator before you use it the first
> time, so that the sequence doesn't always start in the same place within
> the table. If you don't do this, you may notice the same sequence of
> numbers every time the program runs.
>
> Jim
>
>
> -----Original Message-----
> From: Les Mizzell <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
> Date: Wednesday, September 20, 2000 3:35 AM
> Subject: RE: [CF-Talk] Random Images-Resources for Information?
>
>
> >Thanks - will try this and see what happens.
> >
> >What nobody has told me yet though...is WHY *DOESN'T* "<cfparam
> >name="imageswap" default="#randrange(1,7)#">" return 1 through 7
> randomly?
> >
> >Les Mizzell
> >***********
> >Some people say I'm too apathetic.
> >But why should I care?
>
>
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