SimCity had a code sheet with black ink on red paper, where the game would show you a few symbols and you’d have to find the city name/population that went with those symbols on the code sheet. The red paper was supposed to keep you from photocopying it, but the helpful guy at Kinko’s could make a black-on-white duplicate using a color copier.
I’d say maybe 20% of my PC games had copy protection (that I knew of), but then I didn’t have very many games.
If a track is wavy, then it can’t be read by any regular CD drives. Speaking of which, I haven’t heard of it. Cite?
Copy protection on the ZX Spectrum. This was common place pretty much from the start. Like all technological advances there was a constant battle beween crackers and software developers. As soon as one method of protection is created, someone finds a way around it. As soon as the developers discovered a way of copying their software they’d stick in a way of stopping it.
Here’s some of the methods we used, that is the developers:
Use a custom written load routine that ran at a higher speed. This foiled most cracking programs, as the most of the load would all be at the wrong pitch. It also made straight analogue audio copies much more prone to failure.
Use both ends of memory right at the start. Crackers had to reside somewhere in memory. If you padded your program out to the full 48kb and made calls to the memory at both ends when the program first ran then it would immediately fail if the cracker got in the way.
Place code on your screen. Essentially screen memory was just memory like any other, so crackers sometimes hid themselves there. Remedy was to hide your own code on the screen during the load and call it. Again, if the cracker was over-writing it then the program would crash. The skill here was to disguise your code as part of a normal graphic so that no-one could tell where it was.
-Check sums. Add up the code in memory as digits and check the total. Not what it should be? Then you have foreign code someplace, probably a cracker. Time to crash the computer.
The problem I found was that it was possible to construct a copy protection that was so good that it locks the developer out as well! Consequently I have Spectrum games that I wrote but that I simply can’t convert onto an emulator because the copy protection won’t let me. I don’t have the time or inclination to rediscover all the tricks put in to protect it and remove them. 
I have to grin at the methods of copy protection, that often didn’t work due to the efforts of 14 years olds, by a poster of your name **F T ** 
I have to grin at the methods of copy protection, that often didn’t work due to the efforts of 14 years olds, by a poster of your name **F G **
DOH!!
The 80s/90s copy protection died out about the time that CD-ROM became the preferred medium to distribute games. Back in those days, CD burners and CD-Rs were pricey, so for a time, pirates had to spend money to pirate games.
Codewheels seemed to be the #1 copy protection item on the games that I had. Of course, gee, lets see, codewheels are so hard to take apart and copy.
That was something I was wondering XPav. So copy protection was realy prevalent up to the point that most games switched to CD, then lapsed for a few years until it became dirt cheap to burn CDs?
Thats what I think really.
Now, since CD-Rs are cheap, we’re seeing a resurgence of pirating and an equal resurgence of copy protection methods. The methods are completely different this time around. I’ve seen this copy protection for games, but with the exception of high priced software (more than a few hundred $$$), copy protection isn’t really used anywhere else.
CD-key validation with an online server. This works well for online games, with the sole exception being that key generators can generate keys that are possibly the same as valid ones, with the end result being that customers who bought the games get screwed and have to jump through hoops to convince the publisher that they didn’t pirate the game and could they please have another CD-key.
CD copy protection. Safedisc and the like. This has gotten better, but it still sucks, because they’re playing the old game of “make sectors on the disk unreadable”. This causes certain CD drives to go into error correcting mode, and read slower, and do bizarre stuff. Its also easy for dedicated hackers to get around, and mainly serves to deter casual piracy. (The “Hey, Bob, can you make me a copy of Bonestorm?” piracy.)
I just can’t t find the article I read that used the term ‘wavy’.
There is a message board that has a lot of discussions on this topic, but I don’t think I should link to it here. It seems there is a program out that will make useable backups of the new securom. If you would like a link to the site, email me.
For what it’s worth mrblackwell, Safedisk uses a scheme where certain tracks are burnt with alternating bitpatterns such as xyxyxyxyxy (not the real bit-patterns, just an example). Many brands of home CD burners can’t cope with such an alternating pattern. Perhaps this is what they meant by a ‘wavy’ track?