
Atari Centipede’s Hidden Code Trap - jasoneckert
https://arcadeblogger.com/2019/06/29/atari-centipedes-hidden-code-trap/
======
Amorymeltzer
>Simply stating that "this game copied our idea!" is all well and good; but in
a court of law, the case has to be proven beyond any reasonable doubt.

In common law systems such as the US and Canada, "beyond a reasonable doubt"
is generally the metric used for _criminal_ law. Civil cases, such as this,
generally use _preponderance of evidence_ ; it's a much weaker standard,
essentially meaning that whichever side is more than 50% supported by the
evidence will win.

Doesn't take away from the interest in this code trap, but Atari did have a
lower bar for success.

~~~
geofft
Wouldn't this have been criminal copyright infringement, since it was for
commercial gain and impacting the commercial prospects of Atari?

~~~
Amorymeltzer
IANAL (or an expert on Canadian IP law) but while it perhaps _could_ have been
as well, it's pretty clear from TFA that this was a civil lawsuit. Use of the
term "lawsuit" and "plaintiff" (the latter in the only actual document
provided[1]) are dead giveaways, as is the fact that the government (who
prosecutes criminal cases) does not appear to be involved.

1:
[https://missilecommand.files.wordpress.com/2018/12/ilovepdf_...](https://missilecommand.files.wordpress.com/2018/12/ilovepdf_merged.pdf)

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emptybits
The article tells us the non-Atari game retained a damning Morse message in
its ROM. From another source[1] (unverified), this _may_ be the ROM data the
article refers to:

    
    
        .BYTE 2, 0BB, 5A, 30 (where 0 is dot and 1 is dash and nothing for a space)
        .BYTE 5F, 0EE, 7D, 0A8 ; Morse code for "COPYRIGHT 1980 ATARI"
    

[1]
[https://www.binarni.net/2013/07/centipede/](https://www.binarni.net/2013/07/centipede/)

With all the ROM images floating around in the MAME/retro scene, someone can
probably verify this.

~~~
emptybits
Okay, replying to my own curiosity... The above byte sequence can be found in
a dump of Centipede's ROM.

    
    
        00001280  a2 13 a9 ab 5d 20 21 ca  10 fa 85 fe 60 02 bb 5a  |....] !.....`..Z|
        00001290  30 5f ee 7d a8 20 b3 21  85 ae b9 c0 21 85 b0 a9  |0_.}. .!....!...|
    

The entire arcade game is contained in 12 kilobytes of code, BTW. (!) The
amount of imagination and fun and replayability that this era of gaming
delivered under such constraints (by modern luxurious standards) is mind
boggling.

~~~
mypalmike
Spent a little time decoding this...

    
    
      02       BB       5A       30       5F       EE       7D       A8
      00000010 10111011 01011010 00110000 01011111 11101110 01111101 10101000
            C. ..O..P.. .Y...R.. I.G..H.. .T1....9 ....8... .0....A. TA.R..I.
    

*edit: formatting

~~~
stonic
Did you use the source code for this?

~~~
mypalmike
Nah, I just did a little manual pattern-matching on the bits looking for
"ATARI" (morse code : "0110101000") and working backwards from there.

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corysama
A similar technique was used to prove that the mobile game Heroes Charge was
built on stolen code
[https://www.facebook.com/allstarheroes.en/videos/15770877858...](https://www.facebook.com/allstarheroes.en/videos/1577087785877567/)
Except that code has become a lot more complicated since the Atari days. So,
you don't need a hex dump to show the evidence. Just a gesture sequence on a
certain screen and the UI pops up "Copyright: The Original Company".

Meanwhile, the original company was simultaneously being sued by Blizzard for
blatantly knocking off the character designs of World of Warcraft
[https://blizzardwatch.com/2015/03/24/blizzard-files-
lawsuit-...](https://blizzardwatch.com/2015/03/24/blizzard-files-lawsuit-
against-lilith-games-for-copyright-infringement/)

------
Someone
Similar to
[https://www.folklore.org/StoryView.py?story=Stolen_From_Appl...](https://www.folklore.org/StoryView.py?story=Stolen_From_Apple.txt):

 _”Steve decided that if a company copied the Mac ROM into their computer, he
would like to be able to do a demo during the trial, where he could type a few
keystokes into an unmodified infringing machine, and have a large "Stolen From
Apple" icon appear on its screen.”_

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Vivtek
Ha! This makes Rap Genius's apostrophe trap even more delightful, then.

[https://www.rollingstone.com/music/music-news/genius-
google-...](https://www.rollingstone.com/music/music-news/genius-google-stole-
lyrics-morse-code-848781/)

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mordechai9000
So how was the code trap implemented?

~~~
kabdib
I wrote a few game cartridges for the Atari 400/800 computers when I was there
in the early 80s. We were told to include a specific bit pattern, I think it
was 5 or 8 bytes long, somewhere in our code. The idea was that the presence
of a non-functional, unique bit pattern was going to be very difficult for a
defendant to explain in court, since pirates mostly just copied ROMs and made
minimal changes to obvious bitmaps and strings. Even if they found the
mysterious bit pattern and were clever enough to (say) zero it out, they'd
have to explain why most of a ROM was identical except for visible assets and
that one set of bytes with no function ("What are these bytes for? Oh, you
don't know? Let us show you...")

We weren't told what the pattern meant. I played with it for a couple of hours
once; I knew it wasn't executable 6502 code or simple logical bit operation
(NOT, reverse bits, etc.) of anything obvious. Morse code makes sense now.

Some coinop machines (Tempest, for sure) used character encodings so that the
visible copyright messages were also executable code; changing the message,
even slightly, would crash or have unpredictable behavior. In the case of
Tempest, when the "final" ROMs were released to manufacturing, the dev team
went on vacation while production ramped up. Some lawyer decided that the
copyright message had to change, so they patched the ROM on the factory floor.
Unfortunately this modification didn't lead to an immediate crash, but opened
up a hole where the contents of the score line could do things like give you
100 extra lives (e.g., die with the low digits of your score being "50" and
you'd be able to play for free for _hours_ ).

~~~
i_am_nomad
Side note here, the Atari 800 was my first computer, and I absolutely loved
every minute of it. Thanks for all your work and ingenuity, they gave me a
good start on a career in technology.

One question: why didn’t the Atari 800 ever take advantage of the double
cartridge ports?

~~~
kabdib
My understanding was that the second cartridge slot was not a very well
thought out thing. I think there was one cartridge made for it (some debugging
tool?)

That port cost a lot of money per unit; Atari's early efforts were not very
well cost reduced. If they'd been more aggressive about cost reductions (and
improving I/O speeds) they might have done much better in the market against
Commodore. Instead we got more unclear hardware directions (the 1200XL's
"Help" key was a prime example of the hardware group just not caring about or
talking to the software folks), even more expensive machines, and a bunch of
work being done by outside contractors instead of inside staff because it was
easier to build empires that way. The 7200 game machine (developed by General
Computer Corporation in Cambridge, IIRC) was a surprise to most of us, for
instance, and not a good one.

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vessenes
It would have been really rad to tie this embedded message to an input
sequence. I guess in centipede that’s extra hard, but it would make for a
great moment in court when the devs roll in defendants machine and moments
later copyright Atari shows up..

~~~
joezydeco
Jarvis and DeMar did exactly this on Robotron:2084, in the hopes it would be
useful in court one day:

[https://youtu.be/3zr4CdUdt0w](https://youtu.be/3zr4CdUdt0w)

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yitchelle
This reminds of the story why Van Halen had a M&M clause in their contract for
rock concerts.

It is a trap to ensure that the contract was fully read and complied with.

[https://www.snopes.com/fact-check/brown-out/](https://www.snopes.com/fact-
check/brown-out/)

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praptak
>Simply stating that "this game copied our idea!" is all well and good; but in
a court of law, the case has to be proven beyond any reasonable doubt.

This sounds like patents or copyrights can grant monopoly on an _idea_. As far
as I know, this is not the case. (Well, at least not in principle.)

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jeffrallen
Xor ftw!

