[NCLUG] Python v.s. Ruby, and PRNGs

Sean Reifschneider jafo at tummy.com
Wed Apr 9 23:15:52 MDT 2008


Stephen Warren wrote:
 > So, I wrote a quick script that basically does:

So, I'm interested in how well the Linux /dev/random does.  Of course, it
depends on having a good source of entropy.  I'm running a small script to
pull out 100,000 dual dice rolls from a few different machines that I
suspect might have a reasonable source of randomness.  I'll post the
results somewhere when they complete, it looks like it's going to take a
while.

The script I'm using is:

    #!/bin/sh
    for (( i=0; i < $1; i++ )) do
       D1=`od --read-bytes=1 -t u1 /dev/random | head -1 | sed 's/.* //'`
       D1=$[(D1%6)+1]
       D2=`od --read-bytes=1 -t u1 /dev/random | head -1 | sed 's/.* //'`
       D2=$[(D2%6)+1]
       echo $D1 $D2 $[D1+D2]
    done

Probably would be worth trying with /dev/urandom as well.

If I hand some of this data off to you, Stephen, can you plug them into
your script?

Thanks,
Sean
-- 
Sean Reifschneider, Member of Technical Staff <jafo at tummy.com>
tummy.com, ltd. - Linux Consulting since 1995: Ask me about High Availability



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