Computer Dice

Forum Archive : Computer Dice

Does Jellyfish cheat?

From:   Fredrik Dahl
Date:   6 June 1997
Subject:   Re: Deleted Jellyfish

> While I do not consider myself an AUTHORITY on backgammon, I do know
> enough to finally have had enough with this program.
> I put up with some really strange and off the wall wins.  Sometimes only
> occuring after hitting some really very hard combinations.  Now, I now
> that it does happen in real life, but on a consistent basis!?
> I got really curious after somebody had mentioned on this newsgroup on
> how jellyfish behaves after doubling or being doubled, because I noticed
> the same thing.  Over a three day period I played probably over a hundred
> games on the hardest level and doubling every single time.  JF3 won every
> single one of them.
> Enough said.

I guess I'm repeating myself, but you can PROVE to yourself that it
doesn't cheat with the dice. The two numbers SEED and COUNTER (settings
menu) defines the state of the dice generator. If you like, you can
write down these number before starting the game. Before starting the
next game, do 'Swap sides' and reset SEED and COUNTER. You will then see
that you get the same sequence of rolls with you getting JFs dice and
vice versa. Swapping sides is done to make the other player win the
opening roll, otherwise you'll get the same sequence exactly. It does
not take a lot of work to see that the dice rolls are independant of who
is rolling, what the score is, what the position looks like etc.

When you start the program, it uses the system time of you pc to set the
seed, while the counter is zero.

Fredrik Dahl
(Author of Jellyfish)
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Computer Dice

Dice on backgammon servers  (Hank Youngerman, July 2001) 
Does Agushak Backgammon cheat?  (Mr Nabutovsky, June 2000) 
Does BG by George cheat?  (George Sutty, Nov 1995) 
Does Backgammon NJ cheat?  (Greg+, June 2010) 
Does Cybergammon cheat?  (Goto Informatique, Aug 1996) 
Does David's Backgammon cheat?  (Joseph B. Calderone, June 1998) 
Does GNU Backgammon cheat?  (Robert-Jan Veldhuizen, Nov 2002) 
Does Gammontool cheat?  (Jim Hurley, Sept 1991) 
Does Hyper-Gammon cheat?  (ZZyzx, June 1996) 
Does Jellyfish cheat?  (Fredrik Dahl, June 1997) 
Does MVP Backgammon cheat?  (Mark Betz, Oct 1996) 
Does MonteCarlo cheat?  (Matt Reklaitis, June 1998) 
Does Motif cheat?  (Rick Kiesau+, Mar 2004)  [Long message]
Does Motif cheat?  (Billie Patterson, Feb 2003) 
Does Motif cheat?  (Robert D. Johnson, Oct 1996) 
Does Snowie cheat?  (André Nicoulin, Sept 1998) 
Does TD-Gammon cheat?  (Gerry Tesauro, Feb 1997) 
Error rates with computer dice  (NoChinDeluxe+, Feb 2011) 
FIBS: Analysis of 10 million rolls  (Stephen Turner, Apr 1997)  [Recommended reading]
FIBS: Are the dice biased?  (Kit Woolsey, Oct 1996) 
FIBS: Entering from the bar  (Tom Keith+, Apr 1997) 
GamesGrid: Too many jokers?  (Gregg Cattanach, Sept 2001) 
GridGammon: Are the dice random?  (leobueno+, Sept 2011) 
Jellyfish: How to check the dice  (John Goodwin, May 1998)  [Recommended reading]
Jellyfish: Proof it doesn't cheat  (Gary Wong, July 1998) 
MSN Zone: Security flaw  (happyjuggler0, June 2004) 
Official complaint form  (Gary Wong, June 1998)  [Recommended reading]
Randomness testing  (Brett Meyer+, Dec 2010) 
Safe Harbor Games dice  (Michael Petch+, Aug 2011) 
Synopsis of "cheating" postings  (Ray Karmo, Feb 2002) 
Testing for bias  (Kit Woolsey, Jan 1995) 
The dice sure seem unfair!  (Michael Sullivan, Apr 2004) 
Too many repeated rolls?  (Stephen Turner, Mar 1994) 
Winning and losing streaks  (Daniel Murphy, Mar 1998) 

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