Message-Id: Comments: Authenticated sender is From: "Salvador Eduardo Tropea (SET)" Organization: INTI To: G DOT DegliEsposti AT ads DOT it, djgpp AT delorie DOT com Date: Mon, 23 Mar 1998 13:38:29 +0000 MIME-Version: 1.0 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Subject: Re: real random numbers In-reply-to: Precedence: bulk G DOT DegliEsposti AT ads DOT it wrote: > > >If anyone could tell me how to get REAL random generated numbers under > >djgpp ... and/or explain me how it works ! I wonder for a long time how > >a computer can generate random numbers > > I would like to know it too! ;-) > > Computers cannot generate real random numbers, what they can do is run some > program in a deterministic way. (at least PCs do :-) Hmmm... That isn't true, you can easilly create a random number generator using a diode and an A/D, or just sampling the enviroment sound ;-). There are a lot of cases like that, not all involves an A/D converter, some signals (not properlly grounded, etc) have random patterns. You can do it, but you need some hard. > Random numbers on PCs are actually pseudo-random numbers. They are > generated > using some functions with particular mathematical properties: > they return numbers very well distributed on a particular set of values and > IIRC they return the original sequence of values only after a number of > calls > greater then the cardinality of the given set of values. > > This makes the functions look like if they generate random numbers, but > they actually don't! And that's a feature because in this way you can test programs with random values more than ones and with the same values, or use an encripting methode using "random" numbers. SET ------------------------------------ 0 -------------------------------- Visit my home page: http://set-soft.home.ml.org/ or http://www.geocities.com/SiliconValley/Vista/6552/ Salvador Eduardo Tropea (SET). (Electronics Engineer) Alternative e-mail: set-soft AT usa DOT net set AT computer DOT org CQ: 2951574 Address: Curapaligue 2124, Caseros, 3 de Febrero Buenos Aires, (1678), ARGENTINA TE: +(541) 759 0013