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Copy protection scheme that was used for Dungeon Master on Atari ST and Amiga (dmweb.free.fr)
163 points by bigbugbag on Dec 29, 2014 | hide | past | favorite | 109 comments



I wrote some copy protection code for a couple of game cartridges (the idea was to prevent people from trivially copying them into RAM).

One cart protected itself with checksums, computed over time from interrupt code, that were the key to decrypt a piece of code that did the "am I running from RAM instead of ROM?" check. Took me two weeks to write (I had two weeks of hanging around waiting for play testing to finish).

The software pirate who lived in my apartment complex knew I worked at Atari, and we were chatting one day when I mentioned that I'd written that particular cartridge. He lit up. "Yeah, that was a hard one. Took us three days to crack."

Copy-protection can be useful, but it's definitely an asymmetric game.


> it's definitely an asymmetric game.

This. The crackers have to deal with whatever measures were taken by the authors. On the other hand, the authors have to deal with all of the measures available to everyone interested in cracking it.


I am curious, do you feel the time spent on copy protection was worth it given the result?


Oh yes, definitely.

1. The game got great reviews, so quality did not suffer.

2. In the 1980s, distribution of cracked titles was mostly by modem (BBS) or warez disks, and thus a LOT slower than today. Cracks would take weeks or months to get wide distribution.

3. Atari was paying me $30K/year. Let's double that for total employee load. It took me two weeks to write the copy protection, so that's roughly $2500 cost to Atari.

4. I think Atari's profit on carts was about $25. So to break even we had to deter 100 people from pirating the game and just buy it instead. You can wiggle the profit numbers around if you like, but it doesn't change them appreciably -- it's just not that many buyers that we have to swing in order to pay for development.

It's impossible to get numbers, but the fact that the game wasn't trivially copyable by the kid down the street (it took an expert cracker 3 days), that cracks were hard to obtain (little inter-pirate communication, bad distribution systems), and that the title sold maybe a million copies makes it almost certain that the protection not only paid for itself, but did so many times over.


I'm sceptical that the person hacking your console lived in the same apartment complex.


175 Calvert Drive in Cupertino. Kind of a dump in the early 80s, probably all condos now [checks . . . nope, still there. Yuck].

I think one of us noticed the other carrying some Atari equipment in the parking lot, and we started chatting. Sure, a bit unlikely, but this was Silly Valley. I think the guy worked for Lockheed and cracking software was a hobby.

I kind of had this fellow in mind when I wrote the protection code. I figured it wouldn't stand up very long, and in fact, three days was a moral victory as far as I was concerned. I think he had as much fun with the code as I did :-)


> Silly Valley

Fair enough. I suppose that term will stay in my head now.


Games was a much smaller world back then, and pretty much everyone with a 8-bit system had tried their hand at both writing games and hacking other peoples. When you write assembly language yourself, and own a debugger, then everything is "open source".


Well, not for me :-)

I cracked a few games, looked at someone else's code but I can assure you that at the ASM level, it's very hard to understand that phong-shading routine to the point you can actually re-code it yourself...

(yes, I've tried :-))

stF


Depends on the game. Some games had so few comments that they looked pretty much like a disassembly (Pac-Man for the Atari 800 had exactly two comments in it -- one was a copyright statement, the other was "Ha!", on the critical write-to-ROM for its rather pathetic implementation of copy protection).


This brings back memories... I worked at a company that used special duplication devices. We assisted with duplication of the game Rogue, and secured it with the main trick of making one of the sectors on the 5 1/4 floppy (might have been sector 8 or maybe 2, I don't remember which track) only half sized, while keeping the sector's recorded stats set to normal sizing (in the FAT? Not sure).

During game load, the executable would get the PC drive to do some kind of absolute positioning to read the "hidden" half sector, which would exist on these specially created discs.

Any subsequent copies made on normal PCs and copying equipment would copy the half sector as a normal full sector, missing the hidden part.

I remember talk about "fuzzy bits" at the time, but I cannot recall if we used them, and whom for...


Another copy-protection classic was Spyro: Year of the Dragon: http://www.gamasutra.com/view/feature/131439/keeping_the_pir...

This used a multi-layered copy protection scheme. The first layers would show a dialog and quit. Later layers got progressively more vicious:

1. They'd remove 1 out of 10 gems needed to complete a certain level.

2. They'd randomly corrupt data.

3. They'd change the UI language at runtime.

Read the post-mortem I linked above; it's really fun. The basic idea was to require crackers to play the entire game very carefully, looking for subtle side effects that broke game play.

Ultimately, the protection was a success: It took almost 2 months to crack the game, resulting in a full Christmas season's worth of sales IIRC.


> a success: It took almost 2 months

This is all based on the idea that people who pirate games (or movies, etc) are also very impatient. I'm sure that's true for a certain percentage, but I don't know if it's that significant.

A current example is Dragon Age: Inquisition, which took a few extra weeks but still got cracked. But the game still has a ton of issues on PC (even for legitimate owners), so it's probably worth waiting another month or so for patches anyway.


From the linked article:

> Two months may not seem like a long time, but between 30 and 50 percent of most games' total sales occur in that time. Approximately 50 percent of the total sales of Spyro 2, up to December 2000, were in the first two months. Even games released in the middle of the year rather than the holiday season, such as Eidetic's Syphon Filter, make 30 percent of their total sales in the first two months.


First week/month sales are critical to most media, as I understand it. Being a "best seller" can become a self-fulfilling prophecy.

Stymieing the impatient pirates is all you can hope to accomplish anyway.


I think the 'success' was being able to delay the crack long enough for Christmas sales. Although whether the crack would have affected those sales considerably might be debatable.


I remember back in the day I used to crack Commodore 64 software, and some of the best protection I remember was when code was written and executed to the RAM in the disk drive, using the intelligent 1541 drive to verify the original disk was in the drive. It was brilliant, and took me longer than any other program to crack. It required the used of a disk memory disassembler, really obscure stuff.

Sierra software used to use multiple encryptions of the original disk-verification code, if I remember correctly. I feel some residual guilt about it now, but I was 14, and honestly, I learned more 6502 assembler cracking code than I ever did writing it. It was like a puzzle. Sorry, Oil's Well developers.


Reminds me of my run-in with Starforce 5 in my youth (when I couldn't afford games).

It measures how many sectors there are in the rings on the disk. This number was validated against a portion of your CD key. At the time only a specific line of Plextor drives were able to create physical replications (this still might be the case). The Starforce driver prevented use of drive emulation. Removing the protection from the game (cracking it) wasn't simple, they advertise C++ obfuscation and thus likely inlined the protection routine in multiple places.

Two years after its launch the specific game I wanted (Track Mania Sunrise) could still only be pirated if you owned a Plextor.


Nice. If I were writing an emulator, I would naively write a virtual disk drive that always worked. It would never occur to me that some programs would depend on certain reads being inconsistent.

I do wonder, though, if anybody has studied the ROI of antipiracy schemes like this. The only time I bothered to pirate software like this was when I was a penniless kid. And it's clear from this that the crackers were willing to put in absurd amounts of effort to break encryption; if one's opponents aren't rational economic actors, I'd think it would be easy to spend far more on copy protection than would ever get paid back in additional sales.


I suspect (but cannot prove) that it was greater back then.

This was before the Internet was really a thing, so even after the copy protection was cracked pirating software was still a hassle. Pirate BBSes took some effort to discover, and often had download quota systems you'd have to play along with. Even after that, you couldn't download a file without tying up the phone line and if a local BBS didn't exist you'd need to pay long distance charges, both of which risked the wrath of your parents.

So the "dedicated attackers" needed to be somewhat more dedicated, and were therefore rather less common. You could get a lot further by just preventing casual floppy copying, which was sometimes sufficient to discourage friends copying a game instead of buying a copy for each of themselves.

By contrast, warez present essentially zero hassle nowadays. That dramatically alters the equation.


How to say that in english ...

I was very young at this area , but we exchanged a lot of pirated game in school when we was 10 :)

We even find way to copy password manual protection by copying the disk or tunning the photocopier for the password manual in red.

During the school recreationnal time we talked a lot about games and we exchanged games, there was always someones who had a cousin or an uncle.

Great time, i owe a lot to this time and games.

I buy it now as much as i can (gog , re edition etc ...)

I get the atari at this time , and a lot of my friends too. I remember that i may have buy only one game or two with my pocket money because the package and manual were awsome. At this time the box and manuals was what makes me buy games more than pirate then :)


> By contrast, warez present essentially zero hassle nowadays.

And they come with free malware to top!


To paraphrase Tanenbaum

Never discount the bandwidth of an envelope full of floppy disks in the post.


"By contrast, warez present essentially zero hassle nowadays."

It was always easy, it has only recently become harder as online only and F2P has come online. Diablo 3 is a case in point.


on the other hand sometimes protections are (were) lame. I remember probably 16-18 years ago "cracking" a CAD software worth thousands of dollars by just modifying the script used for the installer: the software was using a protection scheme based on some hard drive serial number, so that the activation code cannot be reused on a different system. The problem (for them) is that they implemented this in the installer too and the installer was using some kind of simil-VB scripting for doing the check. I modified it to print the activation code instead of just verifying it and pronto the installer became a keygenerator :D

It had been a great satifaction..


This was a fascinating read. Somewhere in the late 80s/early 90s I picked up a floppy with a guide to cracking at a local computer store. I was then able to crack a few games with help of turbo debugger and Norton disk editor (file editor?) -- I mostly remember looking for int 16 (ah 02?) and then replacing the next few lines with nop's or changing jni to jmp -- I knew little of what I was doing but it was a blast. I was aware of certain protection that read bad sectors on a disk but if you did an exact floppy copy you could usually copy bad sectors-- different than this article. I do remember spending a few days on my cousins copy of altered beast and being very confused by it. I think it decrypted the game from disk or u compressed from disk into me,Roy so I could see the code I wanted to change in the debugger but not on the disk. This may have led to a failed attempt at a TSR to alter the code during runtime. I thi I i e eventually gave up. I also remember finding bible verses in the caveman ugh-lympics dump I think. Fond memories.


I think this or part of this is what was on that shareware disk I got at the computer fair http://www.textfiles.com/piracy/CRACKING/act-13.txt the Buckaroo Bonzai Cracking the IBM PC sounds real familiar.


you may want to read "Technical Documentation - Detailed analysis of the Dungeon Master and Chaos Strikes Back for Atari ST Floppy Disks" too then http://dmweb.free.fr/?q=node/1429

note the PDF at the bottom of the page.


> while most copy protections are defeated in a matter of hours or days by experimented hackers

I'm very amazed by this. How can this even be possible? Is there a standard formula that breaks every copy protection out there?


Quite often these checks are just so simple and half-hearted that once you have even a little experience they're obvious.

A most basic protection, for example, might make the user enter a serial number to register a piece of software. If you enter the correct number then all is OK, if you enter the wrong number a message-box might appear saying "Sorry registration number is invalid".

Displaying that message-box almost immediately makes the cracking job 80% simpler. Disassemble the program, look for the reference to the text-string. Then look for a "compare + jump" that goes to that area of the code. 99% of the time the comparison will be "Is the serial number OK?" and if you remove the jump, or invert it ("jmpz -> jumpnz"), you're done.

If you want to read more you can find mirrors of +fravias documentation and demonstration site online which were live back in the day and introduce this stuff, and lots more:

http://71.6.196.237/fravia/academy.htm


Almost all (?) protection ultimately requires some kind of feedback that you can work backwards from, so it was always a losing battle for developers. In a similar vein, I remember having the Grand Theft Auto 1 demo. Because it was an open world, it had a time limit on how long you could play the game.

The countdown was displayed in red digits in the corner of the screen. I used SoftICE to set a memory write breakpoint on the video framebuffer at the location where the timer was displayed. That allowed me to locate the code printing out the timer. That in turn gave me the address of the timer variable, against which I set another memory breakpoint, which brought me to the routine that was counting down the timer. A 1 byte patch effectively disabled the timer and allowed me to play for hours.


An early favorite of mine was the disk check in Ultima II. Origin used a bad sector to verify original disk scheme.

Consumer drives could not make a bad sector, only firmware modified drives could, and I didn't have one at the time.

Based on some successful cracks I did on the Apple ][, I started working through the code, only to find out they didn't check for a specific error, just an error.

Upon seeing that, I restarted my Atari with the copied disk in the drive. Ataris made a beep for each sector loaded, which was very handy. About 19, or maybe it was 23 beeps later, I opened the drive door waited for the error, closed it, and the game worked just fine.

No need for a HEX patch.


That was how I cracked WinRAR back in the days.

Or better, I got rid of the annoying popup.


Wow. I made dinner for Fravia and crew once. Basically they just showed up at my place, and I was so honored that I raided the pantry.


I got into hacking/coding by virtual of wanting infinite lives for the games I played on my ZX Spectrum. That taught me all about reverse engineering, the R-register, copy protections and similar.

Most of Fravias work was easily understandable, and pretty obvious, from that background. But he really was an interesting character and I was genuinely saddened to learn of his death.

I wish I could have met him.


Somehow I had missed hearing of Fravia. For the curious, Wikipedia has a good article on him: http://en.wikipedia.org/wiki/Fravia


I remember cracking Teenage Mutant Turtles and IBM Writing assistant just with the "debug" tool provided in the standard MS-DOS. It definitely took half an hour or so. The tests were very dumb, that's for sure. Just replacing a "JE" by "JNE" or something like that would do the trick.

I also cracked Ultima 6. That took me 3 days of intense work. The protection was hidden in the dialog engine. So you were not seeing the actual code, but the interpreter of dialogs actually interpreting the protection in the dialog engine (that was a super simple interpreter, more like a state machine). In the end, it was just a matter of understanding the dialog data and extracting the answer to the protection question ("on page 34, what is the third word ?").

I also cracked some football game by writing a program that would intercept disk access and the replay the disk-errors to cheat it. An emulation layer if you like.

The games that I've never cracked were Elite 2 frontier (the damn thing had checks all over the place and that was too hard); "le manoir de mortevielle" had super nasty decryption stuff. IIRC they were running decrypting code inside the interrupt table (so if you had to use the keyboard or timer to trace the code, then woosh :-)). I also went mad on Leisure Suit Larry were the protection was written in an interpreted language. At that time I was 16 or 17 and had no idea of what an interpreter was = >I've never understood the scheme :-(

You had also games with special messages in it such as "we worked very hard on this so don't crack us).

But the best thing I've seen is when I've tried to look into a already cracked game .the previous hacker Mr. Detergent I think, send a message along the line of "you're weaker than me". I Was sooooo upset :-)

I guess I cracked 20 or 30 games on PC. Most of them were very simple. But in the end things were getting harder. I had to use the Soft-ICE debugger (massive thing :-)) and then, well some had these hardware debugger and came the protected mode and, well, I got lost and started working on more creative stuff (Imphobia if one remembers :-))

stF


Having code run in interrupt routines reminds me of some of the hardest stuff I ever had to touch in the 8-bit days.

In the Z80 processor there is a magic register, the R-register, which has a value which increments magically after each instruction has executed. It is possible to calculate how much it goes up by, for example "XOR A" increments R by one, but "LD IX,23000" increments R by two.

If R is given a predetermined value at the start of the protection system, its value is known after every instruction until the loading system starts.

This was used in many of the protection routines on Spectrums, usually as part of code that would decrypt routines, and it was a pain for the same reason that the interrupt would have been - if you're in a debugger you mess up the global state of that register.


This was on occasional occurrence on Acorn's BBC Micro, which was 6502-based and had a 16-bit free-running timer. There were a number of then-little-known details of the 6502's operation and the interaction between the 1MHz timer clock and the 2MHz CPU clock that made it difficult to predict what the hell was going on (on top of the usual code obfuscation tricks).

Interesting thread - well, for former BBC Micro programmers perhaps! - on the topic: http://stardot.org.uk/forums/viewtopic.php?f=1&t=696


That is an interesting copy protection scheme, partly because it'd probably be a criminal offence to write anything like it these days. It contains code intended to silently reformat whatever's in the floppy drive if any of the checksums fail - something that could easily happen if the tape or hardware's even slightly flaky - and because genuine copies are loaded from tape that's going to be an unrelated floppy, quite possibly one with important data on it.


I just can imagine :-) I also learned after that some protections used undocumented processor instructions or edge cases of some... But back in the days, you had no internet, access to documentation was not easy esp. if you were young... So although I regret the lack of friends-like-me by that time, I also appreciate the various tricks of the trades that I've learnt then... Now I write python... That's much easier but it makes programming so much more mundane. Bah, another time, another story :-)

stF


It always ends up as a boolean somewhere.

    /* complicated auth check */
    ...
    /* more complicated auth check */
    ...
    /* etc */

    if(!isValid) {
       /* do nasty things */
       ...
    }
You just need to find isValid and flip its value. Easy cheese in a good debugger.

I used to keep Soft-ICE installed on all my boxes. There were a few copy protected apps I didn't bother writing out the cracked file since I used them infrequently. Instead I'd set a breakpoint right before the e.g. isValid flag. Whenever I'd run those apps, Soft-ICE would pop up and I'd know I need to flip the bit for the full version.


I'm very amazed by this. How can this even be possible? Is there a standard formula that breaks every copy protection out there?

For the most basic protection, find out where the copy protection check takes place, and patch the executable to skip over that check.

Obviously this would only work for the most trivial of copy protection. The basic principle remains the same, though.


In order to prevent disk copy, the games make use of "fuzzy bits", also known as "weak bits" or "flakey bits"

Reminds me of the "weak sector" protection used on CDs, of which there was much technical information written on a few years ago; sadly a lot of that has somehow disappeared, but I managed to find one explanation of that scheme:

http://web.archive.org/web/20090603002402/http://sirdavidguy...

(The explanation there is not completely correct - the problem with more 0s than 1s or vice-versa is DC bias, since the signal from the read head is AC-coupled; here is another article that might help to explain that better: http://ixbtlabs.com/articles2/magia-chisel/ )


I have never heard of fuzzy bits. I have found this if someone else is interested in it. http://www.atari-forum.com/viewtopic.php?t=9012


What do people use for drop-in debugging nowadays? SoftICE's original company went away a long time ago, and last I checked, the company that bought the code (and rebranded it something like Driver Studio) is also no more.


I wonder: which software is the hardest to crack nowadays? As a hobby musician, I know that Ableton Live and Cubase seem to have excellent protection mechanisms, as this topic turns up regularly in forums. Especially Ableton seems to be nasty, as it is often usable for many hours before the protection kicks in. I think this is pretty clever, since it not only makes it harder for the cracker, but the user might be more inclined to buy the software after he has invested many hours in some music he cannot load anymore (Disclaimer: I own Ableton Live, and it is worth every penny.)


bitwig is better imho, on the single point that it doesn't lock user to a specific OS.


Some of the most painful games I've had to crack were those that used obfuscated assembly (usually by xor'ing entire sections of code). This had the annoying effect of making it impossible to put breakpoints too far ahead of the code because assembly debuggers put breakpoints by modifying the opcodes (usually calling an interrupt) so by the time the unrolling routine comes along, it will decode the wrong bytes and you'll get garbage (and usually, a nice lock up or reboot).

The only way around that was to painfully go stage by stage, which was very time consuming.


Remember that from when I was a teen, the first crack took months after the initial release and came on like 20 disks, while the retail game was on 10 disks. Kevin R. Kachikian is the name on the patent, currently he is CTO at Amuse Inc. according to his LinkedIn page - must be a very smart guy.


Mm, it didn't take all that long to crack, when I did it for fun. My patched version of Mon had a reference search, and the code in the graphics.dat stuck out because I was single-stepping from interesting places. That trick makes deadlisting harder, but live debugging there's no real difference.

Side note: it kept the XBIOS/GEMDOS keyboard/mouse drivers in place, tried to unlink a debugger and wipe the RAM - but it forgot to patch out the good old Alt-Help "screen print" vector! So if you hide a routine in low memory, just above the vector tables, but below where it wiped, around $200-$400 ish from memory… <g> (Oh, and a Syncro Express would just duplicate the thing cold, even on Express mode, but that's no fun~!)

Chaos Strikes Back was bloody difficult as a game! Wonderful work, all around, it's a masterpiece. I bought more than one copy (and actually played Dungeon Master after CSB). I never did finish CSB!

On a similar thematic note, the later, futuristic first-person dungeon crawler Captive has much more interesting copy protection; the author (ratt) wrote his own disk routines (internally called RATTDOS). That was a tough one. It's very Amiga-ified inside, so I wouldn't be surprised if the Atari version shared most of the code. It has procedurally-generated levels, although I think it may be impossible to complete after a certain point.

The Atari ST version of Sid Meier's Civilization is also well worth checking out as a historian; it was written in C, and they left all the debugging symbols in! Fascinating; you can see the original "nuke-happy Gandhi" bug underflow first-hand, and the world maps were really just planar bitmaps, so when you'd figured out how they were stored, it wasn't hard to knock up an editor.

I also have fond memories of Wayne Smithson's Anarchy and its disk's Rob Northen exotic copy-protection's space-filling rant, although I suppose there are only a few people who even know what I mean about that. If you can find an original copy intact anywhere, break out a sector editor, and start reading. The format gets harder the further on in the disk you go. :)

To the person below who had trouble with Elite II: Frontier - um, perhaps your platform was harder? The executable we all seemed to have on the Atari was standalone, was one $4E75 RTS away from skipping the manual protection, and had absolutely no checksums in it at all (to my immense glee - I had lots of fun modding it)! I'm having some fun downtime playing its recently-released sequel Elite: Dangerous, too - but that's online, so of course I'm playing clean! (I did test a couple of cheats during the alpha, and reported to help the devs patch some of the most obvious gamebreakers.)

Other than online stuff, I honestly don't think they've discovered any particularly new tricks since those days. There's a lot of lost gems that get reinvented. The very best, newest, "anti-tamper" techniques are essentially, just bits of obfuscated code interleaved with checksums. Underwhelming, really. It boggles my mind that people still do that stuff - just make it easier to buy games, and it's hard to get easier than Steam! (My opinion of the "strong" obfuscation technique that bloats simple 32-condition IF statements to multi-gigabyte sizes is also pretty poor, as it stands at the moment, although the state-of-the-art could always improve.)


Hey! thanks for this instructive comment.

I too had not managed to finish CSB at the time, but when it got ported to PC[1] with a feature to record your games, it spawned a speed run competition and I was shocked to learn that it can be defeated in less than 30 minutes, actually best time is 00h10m37s[2].

I gave it another try and manage to beat it after a few attempts, there's much trickery in how the dungeon is designed with falling traps on top of others and teleporters, but once you get your head your head around it and understand the diabolical demon director, it gets better.

Then there's the custom dungeons, and conflux is the real challenge, CSB is walk in the park in comparison.

[1]: http://dmweb.free.fr/?q=node/851

[2]: http://dmweb.free.fr/?q=node/856


Agreed, it has a number of very interesting features in how it gets around limitations in its own engine!

And 10 minutes? Heavens above. Tell me that's tool-assisted.


Yes but in a limited way, the rules says you are allowed to load your savegame in dmute to find the location of the necessary items that are random.

So you can start a number of games and check the location of those items until you get one that suits you and play that game, which usually leads to finishing the games in a few hours.


Just an observations -- nice to see other Atari ST users in this thread -- it was a unique machine at a time where very little did what it could do at it's price point between gaming/computing/animation/music/desktop publishing/software development. It was quite a capable foe to the Mac at the time.


God how I lived, breathed, loved and adored Captive! I think it's the only game I've ever truly fallen in love with.

I still can't face trying it in an emulator and having the spell potentially broken.


I don't think that ruins it, really. It's also quite a loved game, although it hasn't been recreated like DM has. The lack of instructions was just criminal - there was a lot of the game that you had to learn by trial and error and you weren't given a lot of guidance!

The multi-way switches were a bit cheap, but the atmosphere and the little details were wonderful. The engine was very technically strong, too.

You should definitely check out Legend of Grimrock (and its Ishar-inspired sequel?) if you haven't already. I think they're on sale at the moment.

Speaking of Ishar, its copy-protection on the Atari deserved mention. Absolutely loaded with checksums, and it jams the reset vector, and it skews a protection track between two tracks and repeatedly changes tracks and reads at the same time to try to pick it up (which is what that strangled sound from the drive is!). I doubt that does your drive a lot of good, and it failed sometimes, which was… irritating.


Haha, I could never make my mind up about the lack of instructions. As a framing device - "I've just woken up on a space station and know nothing" - it did the trick. Still damned painful though!

The atmosphere really was very special, the small effects of hearing space-station doors opening somewhere, and waiting for the new horror to be found after you've just wasted oodles of cash on a new weapon you can't operate and don't know what ammunition to buy for... special times.

Thanks for the recommendation, Legend of Grimrock looks great :-)


Some programs had embedded graphic subroutines executed when under debugger. It would set CRT frequencies too high and blow up the display.


Sounds like a myth. No crt producer would allow such a case and even if it is true, I would expect lots of law suits.


I'm not sure, but I never saw it as a trap payload.

Rather, it's something that could go wrong when overclocking, since the Xtals were often locked to the video sync rate (my Falcon's "Nemesis" was a real bugger for it); maybe it'd try to change into a mode that actually didn't have the clock it was expecting!

I don't know about "blowing up", but yes, if you put a bad signal into them, some of them might break. I had (probably still have, actually, somewhere, albeit modified for SCART with an LM1881 and my crappy soldering!) an Atari SC1224 RGB monitor in which you fed the horizontal and vertical sync frequencies separately (rather than composite - hence the LM1881 being needed to split the sync). And at one point I had a Falcon, with Nemesis, and Videlity. The monitor did NOT like it if you fed it a horizontal sync outside the 15.6-15.8KHz range (like, say, VGA's 31468.5Hz; oops!).

The result was the big transformer in the back (line output transformer?) heating up and whining and the caps building up voltage, the screen's black level warming to an alarming dull green… I don't think I'd have wanted to keep the power on another few seconds! Although it'd probably only have burnt something out, I didn't want to break anything.

Point is, some CRTs are a bit more… direct than others. I hear the vector monitors (as used in Tempest) are particularly hairy beasts.


While this case might be a myth, there are plenty of documented "killer pokes": http://en.wikipedia.org/wiki/Killer_poke


There were failure modes they didn't always think about.

I once killed off an 80's era TV I was using for a display on a microcontroller. At the time, I was writing low level NTSC driver code, and was abusing the standard a little for some color advantages.

A combination of bright screens, overly dark ones ( sync in the visible raster), and misplaced vertical blank pulses popped that TV. It never displayed the same again.

Still worked, but was just crappy.

As monitors age, they can become vulnerable to this kind of thing. Not so much a single value, or poke, but ugly code intended to stress a display could take a few of the edge case ones out.


It was a fairly common thing, I think? Modern CRTs can detect out of range inputs but at one point you just had to be careful not to supply out of range frequencies. No more onerous than putting the right fuel in your car...


I blow up 14 inch VGA display in Linux by setting wrong horizontal and vertical frequencies.


If all that time, effort and brainpower had rather gone into making it a better game, they likely would have done a whole lot better in terms of reach and ultimately, profit. However copy protection was the standard method in those days, so one can only speculate on what might have been.


It's rated as one of the top (if not the top) games of its era. It was the all-time top seller on the Atari ST platform in question.

They did great with the resource allocations they chose to make.


What was great about wasting any resources on copy protection instead of using them for something actually useful for users?


"Waste" means "use" with a negative connotation. The good thing about spending resources on copy protection may be that the developers were able to make more money on sales. I don't know if it's true.


That's the point. Copy protection doesn't help making any money on sales. It only reduces them. It's a common fallacy of DRM proponents which they like to repeat (that DRM helps them increasing sales).


This is detailed in the article. If it were easier to go out and purchase the game than to copy it, then you'd be more willing to do so.

The problem these days is that it's ridiculously easy to crack DRM, so it's often useless. Back in those days, you needed specialized equipment to get a perfect copy, so you had no choice but to buy the legit game. Therefore, it did, in fact, increase sales.


> Back in those days, you needed specialized equipment to get a perfect copy, so you had no choice but to buy the legit game. Therefore, it did, in fact, increase sales.

There was almost never a point in time where you needed more than perseverance. A debugger was usually enough, given enough time and determination, to strip any copy restrictions - and while the time constants have changed, it is mostly the same today.

And whether or not it increased or decreased sales (even back then) is not so easy to decide. A penniless 10 year old would pirate everything but buy nothing even if it was successfully copy restricted -- due to lack of applicable resources.

A gainfully employed person with something to lose would rather pay a reasonable amount than face the hassle and potential lawsuits -- although that is often predicated on getting a "taste", which an unrestricted copy (whether DRM broken or demo from download or a magazine cover) provides.

Personally, I buy all music I have copies of. If I wouldn't pay money for it, I don't waste space on my hard drive.


> Back in those days, you needed specialized equipment to get a perfect copy, so you had no choice but to buy the legit game.

Yet it was cracked and cracked copies were floating around all the same. DRM was stupid then, DRM is still stupid today and will always remain so.

I.e. this claim:

> That partially explains why they sold lots of copies!

is simply false. Copies were sold not because of copy protection, but despite it. I.e. users are always annoyed by DRM, by inability to back up their games and etc. So they are less likely to buy it to begin with.


Happy to contradict but I can witness as a pirate kid with no money that I saved over months to buy both dungeon master and its sequel, the only two games I ever bought for my atari st. I bought them because they were incredibly good games and due to them being unavailable in fully cracked version at the time.

Also when you bought the game, it included a way to get a backup disk as a mail-in offer:

[Al] A.HORTON I hope my question is not redundant. Three people in my home play CSB. I would love to back it up, but can't. Is there a way that key disks, doc copy protection, or code wheels could be used as copy protection?

FTL Actually, we think our current protection is less hassle than a code wheel or manual based protection. Also, we do offer a backup disk as a mail-in offer. (see the front of the Manual.) http://dmweb.free.fr/?q=node/94


> So they are less likely to buy it to begin with.

You and I, perhaps, but the majority of users? I doubt it.


There were studies which showed that DRM is likely to reduce sales. But it's rather self obvious. DRM cripples usability in some way. Worse product means less potential interest from the user. Not to mention that DRM is simply insulting, and insulting your own users sounds like a bad idea to increase sales.


I'm aware of those studies and an anti-DRM proponent, but this has all to do about how it's done nowadays and whom it profits.

It's not done with the user experience in mind, which is quite different with the dungeon master protection which allowed to play the game for a while (it was even possible to finish it with well timed saves but not see the end scene). Video games now are an industry and most come from major corporations in it for profit which means DRM are badly done, slapped on a game as an afterthought (see below why it's bad)

Besides DRM are a joke for crackers while on the other hand the dungeon master protection caused much respect from the crackers of the time:

What's the best job of a game crack (ST) you have ever seen?

Dungeon Master. It seemed to be written in some kind of interpreted language which made it very difficult to fathom. It also had protection embedded throughout the game. Good protection is like good encryption, it can never be an afterthought, you can't buy it off the shelf, it has to be part of the fabric of the game. Apparently it had a protection check after the final boss, just so you couldn't see the end sequence. Hats off to them. Hats off to Was (Not Was) for cracking it.

http://web.archive.org/web/20081121032254/http://www.dbug-au...


>some kind of interpreted language which made it very difficult to fathom

Oh, Andy… It was compiled C. :-) I thought the structure was nice, actually.


Except this doesn't apply for Dungeon Master, first because it is a great game as in a genre defining kind of game and secondly because at the time teenager me had dozens of games for my atari st all but two were copied: dungeon master and chaos strikes back (sequel to dungeon master).

Why ? because when I got my hands on the copied versions of the game it was badly cracked but still allowed me to play long enough to really get into the game until the party unexpectedly died.

Which means increasing sales is made through making really good games and that piracy channels can be leveraged to increase sales.


Copy protection doesn't help making any money on sales. It only reduces them.

Are you aware that commercial piracy used to be a big thing? You could walk about your local market and see pirated copies of games on sale for a quarter of the price.

These pirate sales absolutely had an impact on "real" sales, e.g. it was pretty common for parents who didn't know any better to buy a game in passing.


> Are you aware that commercial piracy used to be a big thing? You could walk about your local market and see pirated copies of games on sale for a quarter of the price.

Did it change much? Except now all that is available through torrents and so on and even for 0% of the price. While DRM didn't prevent it then and doesn't prevent it now. All it does is annoying legitimate users who buy the product, and as well gives some control freaks tools to shape the industry and the law (with DMCA-1201 like methods).


>While DRM didn't prevent it then and doesn't prevent it now.

Current generation console games are pretty well protected with their DRM and sell much better than their PC ports. Care to explain how it works with the theory that the DRM kills sales and gets cracked immediately?


Console games aren't "protected" by DRM, they are "protected" with reducing their portability. And those companies (like Nintendo) try to attack those who produce emulators. I.e. they want to control how you use the product. It's not about piracy, it's about their desire for control.

When Geohot tried to distribute tools to strip DRM from PlayStation, Sony was all rage and sued him. As I said, DRM is about control freaks trying to shape the industry with corrupted laws, not about any piracy or the like.


Sorry, I understand you rage, but I don't see an answer to my question. On the other hand, an angry outburst is a kind of answer too. I assume your theory failed here.


The answer to your question is, that DRM doesn't help console games in the least. It helps some companies like Sony to control the market with lock-in and restrict what users can do using corrupted laws. DRM itself can be broken and will be broken as the practice shows.


I never said it helps. I asked how you reconcile the believe that DRM hurts sales with the better sales on the system with uncracked DRM. If you consider much smaller installed base and much higher price the console sales are even more amazing.


I'm not sure what you mean by better sales. Some cross platform games which sell better on consoles than let's say on PCs? And why would you think that DRM is the reason for that?

A lot of such games have poor quality on PCs, and more focused on console UX, or there can be tons of other factors which affect it.

Also console manufacturers cultivate lock-in approach and push for exclusives rather than preferring cross platform games. So sales numbers aren't indicating normal competition.


As I said, I am not saying the DRM is the reason. Though I suspect it helps. When people cannot steal things they want - they do buy them. Not everyone, but there seem to be enough such people.

>A lot of such games have poor quality on PCs, and more focused on console UX, or there can be tons of other factors which affect it.

Sure. But games like COD are pretty well done on PC as well. Yet they sell a small fraction on PC even compared to a single platform. You seem to be very sure the DRM reduces sales so should not it be a slum dunk for you here? A system with a strong DRM vs a system where a "strong" DRM means a crack will come out in a month. Where sales will suffer? Where do they actually suffer? It's not some rocket science, the numbers get published every once in a while and everyone who ever shipped a multiplatform title knows them as well.

>Also console manufacturers cultivate lock-in approach and push for exclusives rather than preferring cross platform games.

Obviously I am not asking about exclusive games. Exclusive games do not get PC ports, do they?


> When people cannot steal things they want - they do buy them. Not everyone, but there seem to be enough such people

Or may be those people don't want to buy them, but if they get it for free from pirates, they infringe. And if they don't get it, they ignore it. So far I didn't see any studies which showed that DRM increases sales. But I saw studies to the opposite however.

> Yet they sell a small fraction on PC even compared to a single platform.

Because gaming platforms were unnaturally shifted to consoles by MS and the like? They tried to kill PC gaming market on purpose (consoles give them more monopolistic control). So disproportional amount of console gamers is not surprising. I suspect it has much bigger impact on sales numbers than any DRM can have in either direction.


>But I saw studies to the opposite however.

Well, we are running in circles in here, are not we? These studies do not seem to be able to explain why the console DRM is not reducing sales. So you come with some other explanations instead of DRM. Which is something I expected because the whole premise seems very unnatural to me. Some intrusive and complicated DRM schemes might be able to affect sales negatively but there are just not that many people who have emotional reaction to DRM. I would not buy a game that required me to enter code from manual myself. I would not buy a game that depends on some central server verification. Not because I am religiously opposed to DRM but because it's asking for too much of my attention. I am just fine with console games - they just work.

On the other hand, the PS2 modchips required 20+ wires soldering and expensive at the time DVD-R technology. A lot of people went for that. So, while there are some people who infringe just because it's free, there are also people who infringe just because it's somewhat cheaper. The later category is converted to paying customers with the DRM.


> These studies do not seem to be able to explain why the console DRM is not reducing sales.

How do you know it doesn't? I don't think you have any easy way to measure that. As I said before, console sales numbers relate to the way the market shifted. They can as well be even higher if not for DRM.

> Which is something I expected because the whole premise seems very unnatural to me.

The premise is very natural. Reduced usability means crippled product (in some way). Crippled product means some users will more likely to avoid it. Pretty straightforward and iron logic no DRM proponent can deny. But they don't function according to common sense, or as I already said they use DRM not for anything related to sales, but for completely different reasons.

> while there are some people who infringe just because it's free, there are also people who infringe just because it's somewhat cheaper.

And of course there are those who break DRM for sport just because they like breaking it. I.e. if not for DRM they wouldn't even have paid attention. A clear example when DRM boosts piracy directly.

> The later category is converted to paying customers with the DRM.

Not at all. The later category stays a non paying customer, since why should they buy the same thing with DRM when pirates offer them it without it? I.e. without crippled usability? The only thing that can convince them to become paying customers is the same product offered without DRM by legitimate source. That's because that DRM is always broken.


> How do you know it doesn't?

What you are engaging into (and in pretty much every single message I've seen you post on the subject of DRM) is shifting the burden of proof. This is the same kind of argument we get from creationists or people who want the world to conform to a mental model they have ("The Earth is 4.7 billion years" "How do you know, were you there?").

Strong correlations have been observed between the presence of DRM and strong sales (for games that are worth it). The most obvious examples of this phenomenon would be World of Warcraft, Sim City 5 and Diablo. These games are very close to being impossible to pirate, are extremely high quality and have sold millions of copies.

All you have against the claim that DRM for good games seems to help sales is requesting certainty, but you're the one making the claim that DRM hurts sales, so the burden of proof is on you. I know you really, really want it to be the case, but so far, you've offered very little convincing evidence (not even circumstantial).

I dislike DRM and as a regular buyer of games, it's often been more of a pain than anything else, but I'm also a software engineer and I can't help but acknowledge that it works with sales.


The burden of proof is on those who introduce the preemptive policing. It's their idea to accuse everyone in advance.

There was already proof that DRM decreases sales however. But I've seen none that it helps anyone except those who pursue lock-in and other corrupted practices. DRM has no place in any ethical business.

> Strong correlations have been observed between the presence of DRM and strong sales

Can you point to any studies on this subject please? There are published studies in the other direction. Sales numbers can't simply be attributed to DRM because DRM is broken. Even latest upstart Denuvo was broken not long ago. So the theory of sales coming from DRM is easily refuted by reality.

> All you have against the claim that DRM for good games seems to help sales is requesting certainty,

No, what I have is certainty that DRM serves nothing related to sales. If anyobe still thinks that DRM is used for sales they are simply delusional or are akin to Lysenkoists who thought that plants can be trained to grow in cold climate.

> I'm also a software engineer and I can't help but acknowledge that it works with sales.

And your acknowledgement is based on what exactly? All engineers I spoke about it clearly say that DRM is dumb and never serves any useful purpose (and if it serves any, that purpose is crooked).


> > Strong correlations have been observed between the presence of DRM and strong sales

> Can you point to any studies on this subject please?

I said "have been observed" and I gave three examples of games where DRM correlated with strong sales.

You are still repeating "There are studies proving the inverse" without ever referencing them.


Lot's of things can be observed. Conclusion of correlation or rather causation is purely speculative however.

What I'm repeating and will be repeating is that such unethical methods like DRM have no place in any decent business. And they don't help sales of course. All they help are some crooks who want more control over the market or technology (DCMA-1201 and similar laws is their leverage on top of DRM).


Well, we have the same game selling much more on "crippled" platforms than on PC despite higher install base and cheaper price. If you want to say that without DRM it would be selling even better you have to present some proof. For example, what would have happened if a console's DRM had been cracked in a way that everyone could download game ISOs and play without doing complicated modifications to the hardware like they can on PC? Why, this has actually happened to Dreamcast. Its title sales have not increased because of this, in fact, it has tanked so much that Sega has retired it soon after this happened. But, of course, Sega is run by some reality-ignoring cretins, their sales actually increased, right?

>Not at all. The later category stays a non paying customer, since why should they buy the same thing with DRM when pirates offer them it without it?

Pirates are not offering the PS4 and X1 games without DRM. Please, talk about something you know.


> Pirates are not offering the PS4 and X1 games without DRM. Please, talk about something you know.

Because their DRM is one of the most intrusive ones. It will be broken as well, don't worry. No DRM will ever be unbrekable, that's the nature of it. Of course the more intrusive garbage they pile into it, the longer it can take to crack it. PS4 and XB1 won't be an exception though.


The game selling well in part thanks to its copy protection is what allowed to finance sequels after that.

In that sense, the copy protection certainly benefited the users.


I'm not sure how they could conclude that it was selling because of copy protection and not because it was a good game.

The way I see it, games with DRM sell despite it, not because of it in any way.


Nah. Probably took them a week or two. Getting ahead of piracy was (maybe still is) a big deal.

Making the game better -- if the game is already good -- is unlikely to pay off as much as reducing the amount of piracy in the first few weeks of a title's lifetime.


I sincerely doubt it. Dungeon Master was the all time best-seller on atari and maybe also on amiga, It has spawned a whole genre of games and is still a reference and is played to this day 25+ years later. It gained a cult following among people who played it to the point that one published a fully reverse engineered code in early 2014: http://www.dungeon-master.com/forum/viewtopic.php?f=25&t=298...


Indeed. And some never learn, otherwise DRM would have been dead by now.


I've heard this before, but I disagree with it.

I used to run my own application company and sold windows apps. I could directly correlate piracy with sales. If my latest version had a key generator+crack on the various torrent sites, my sales would go down by as much as 30%. This was mostly because the torrent sites can easily get good keywords on Google and even get results above my own. I essentially had to complete with myself.

It would also waste my time with customer service. A user would have a cracked version installed, get malware, and then expect me to come to the rescue (and of course blame my software for their poor choices). The nerve of some people!!

Large companies like Adobe and Microsoft can take the hit, small shops can't.

But, these days are over now. I created a SaaS out of all of my apps and now have more sales than ever (and guaranteed monthly income). I can see more companies doing this to combat the environment that piracy has created. It's why Stallman is getting so ornery about it lately.


I can see more companies doing this to combat the environment that piracy has created. It's why Stallman is getting so ornery about it lately.

Just for clarity, I doubt very seriously that Mr. Stallman disagrees with SaaS because it combats piracy. It is my understanding that his disagreement comes from the lack of options that are available to the consumer of those services: the freedom to take your data elsewhere, the freedom to audit [and possibly modify] the source code and probably 50 others that I don't even know.

On a separate note, I cannot even fathom a user who would call customer support for a cracked version. The only plausible situation I can imagine is that their child installed the app, cracked it and the parent wasn't savvy or strict enough about knowing where the child got the program and just assumed it was legit and therefore subject to support.


I've seen casual piracy in business environments before. Some people simply don't care.


Open source software doesn't need protection from piracy.


Re your last paragraph, you're massively underestimating how stupid people can be/how much they don't care.


"On a separate note, I cannot even fathom a user who would call customer support for a cracked version. The only plausible situation I can imagine is that their child installed the app, cracked it and the parent wasn't savvy or strict enough about knowing where the child got the program and just assumed it was legit and therefore subject to support."

I sold B2B apps. These were small business owners emailing and calling us about cracked applications.

Some installed them unknowingly because they searched for our app on Google and thought that a site that offered a crack+download combined was our actual site. Others just didn't see a problem with it.

15 years ago, A friend of mine wrote an app for managing state forms for law firms. He eventually went out of business because lawyers not only would not pay for his software (they would just share it with all of their lawyer friends), but would laugh in his face when he tried to go after them for any kind of money.

My point is that with this sort of unethical behavior that seems like is getting more and more prevalent and accepted, businesses have no choice but to change their tactics to survive. Which means creating a service.




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