What is the seed number in random number generation?

[superluminal]

I want to know more about random number generation and how the software packages, like MATLAB, generate noise and random numbers.

What is the seed number? How exactly is it used to generate random numbers? Why do I find it, by defualt, "-1" in those programs? Are there any limits for it? How it will affect the "quality" of randomness?

I don't search for a code or algorithm, just I want to understand how it works !

Thanks in advance.

 

[dainis]

**broken link removed**
**broken link removed**

 

[Antharax]

Allot of times it's like this:

The random function is more likely a pseudo random function generating outputs with a certain distribution (uniform, gaussian, ...).
This means that when you give the same seed, the function always gives the same outputs in the same order.

The seed is the thing which makes it "random". Time, ticks since startup, a sequence on the keyboard (with pauses between keystrokes), ... can generate a +- random seed. Another seed generates another random sequence.

Antharax