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2answers
18k views

MS Excel: Unique random number generator within a range

I searched for a similar question but couldn't find one.. I want to generate 10 groups out of numbers ranging from 1-60 (including both), with each and every group containing random and non-repeating ...
7
votes
5answers
11k views

how do you make a letter password generator in batch?

I'm having a hard time figuring out how to make a password generator with random letters in it. For example, ASWED-ASDWAD-EFEST. So far I can only make random numbers by using the code @echo off ...
3
votes
3answers
545 views

Does 'urandom' share the same entropy of 'random'?

Does the entropy pool /dev/random used the same to /dev/urandom? I want to mknod /dev/random 1 9 to replace the slow random, I think the current entropy is randomly enough, if urandom is based on ...
0
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1answer
187 views

Not quite grasping /dev/random and /dev/urandom

I am not quite understanding the difference between /dev/random and /dev/urandom on Linux systems. What does it mean to run out of “entropy” and how does the system get more? What does it mean when ...
595
votes
18answers
69k views

How are pseudorandom and truly random numbers different and why does it matter?

I've never quite got this. Just say you write a small program in any language at all which rolls some dice (just using dice as an example). After 600,000 rolls, each number would have been rolled ...
23
votes
5answers
19k views

Why is my /dev/random so slow when using dd?

I am trying to semi-securely erase a bunch of hard drives. The following is working at 20-50Mb/s dd if=/dev/zero of=/dev/sda But dd if=/dev/random of=/dev/sda seems not to work. Also when I ...
1
vote
1answer
410 views

How do computers generate random numbers? [closed]

How does a computer generate 'random' numbers? How close to truly 'random' can a number generated by a computer actually be? Is there software / programming language out that that might generate a ...