Questions tagged [copy-protection]

For questions about copy protection techniques used on retro software.

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26 votes
2 answers
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Which software was the first to use copy protection?

While researching early magnetic storage around 1980, I've come to ponder if we know of the first piece of software on removable media that employed copy protection? The Wikipedia article mentions ...
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12 votes
3 answers
2k views

Disk copy protection schemes for Apple II

I have a vague recollection back in the late 70s of using a wonderful program called Locksmith (from memory, so I could be wrong). It apparently could handle all the different ways that disk-based ...
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2 votes
0 answers
300 views

Was the SNES really a "highly pirated" console? [closed]

I just watched the YouTube video How Nintendo Stopped Bootleg Games on the Nintendo 64. The presenter claims that the SNES had a massive pirate scene and you could "easily buy" one of ...
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6 votes
3 answers
548 views

Were commercial Amiga floppy disks shipped with write protection?

In this Amiga "quick kickstart guide" magazine thing that I have from when I bought an Amiga 1200 long ago (it seems to be printed in late 1995), they really go out of their way to point out ...
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7 votes
1 answer
640 views

What's the point of the CPS-2 suicide battery?

The CPS-2 arcade board contains a suicide battery that will force the board to kill itself when it runs below a certain power threshold. Supposedly this was created to mitigate piracy of the games, ...
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2 votes
2 answers
1k views

Why does changing a DOS/Windows EXE cause it to not run? [closed]

If I hex-edit an EXE for DOS or Windows, by adding or removing some text for example, it will no longer run. If I just change a single char around to a different one, it may run. Is this some anti-...
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3 votes
1 answer
198 views

Where can this "boot.B" file be coming from on this Spectrum TR-DOS disk image?

After working on some tools that parse the TR-DOS disk image format .TRD files for a while I just noticed that one of the game disk images I had downloaded "La Abadia Del Crimen", only has three files ...
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6 votes
1 answer
624 views

What is the Nintendo 64 IPL3 and how could it be created by Rust developers?

I was delighted to learn there is an integrated toolchain for Rust development that supports the Nintendo 64. According to the documentation: For copyright purposes, the IPL3 binary is not included ...
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3 votes
3 answers
479 views

Pirated spreadsheet software introducing intentional errors?

Was there ever a case of a spreadsheet application introducing intentional floating-point errors when it detected that it had been pirated? Particularly errors that were small enough to go unnoticed ...
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10 votes
6 answers
2k views

Copying tapes "back in the day"

Back when I had a ZX Spectrum 48K, I had a friend that had a 128K and we would swap games for the weekend from time to time. We did try and make duplicates of the tapes (yes, I know, but we were ten ...
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43 votes
3 answers
5k views

How did Apple II BASIC programs protect against listing?

I seem to recall from my high-school days that certain Apple II programs protected themselves from being listed and therefore modified. If you tried to do it, the machine would simply reboot. How did ...
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13 votes
2 answers
2k views

Weak bits on floppy for copy protection

How did the vendors using copy protection create weak bits on the floppies? This always fascinated me as a kid. I ended up finding a weak bit emulator that would intercept the floppy disk interrupt ...
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4 votes
3 answers
2k views

How can I view BASIC code hidden by SYS?

I ran a validation of an old disk, and it turns out this ruined a game (won't load) and deleted my old high score list on David's Midnight Magic. I would like to edit the code to get the high score ...
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5 votes
0 answers
430 views

Rainbow Technologies Ltd DRM system for DOS

A number of games from the early 1990s appear to be protected with a DRM system developed by Rainbow Technologies Ltd. The system allows content in the games to be unlocked by sending the manufacturer ...
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10 votes
4 answers
979 views

Was the Amstrad's file protection considered secure in 1985?

I just reverse engineered the file protection on the Amstrad CPC, which uses two sequences of rotating bytes taken straight out of the AMSDOS ROM to XOR each byte of the file. If you have SEQa of 13 ...
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12 votes
2 answers
1k views

How was Prince of Persia "better/faster" with RWTS18?

I was reading about Prince of Persia over at POP Code Review. In that article, the writer printed an interview with Roland Gustafsson, the inventor of RWTS18 copy protection for the Apple II series. ...
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8 votes
3 answers
871 views

Advantages to installing a parallel port in a C1541-family drive other than speed

Are there any advantages to installing a parallel port in a C1541-family drive and using a parallel cable to a PC to image disks, other than increased speed (i.e. since the standard IEC protocol is ...
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21 votes
3 answers
2k views

How did "full memory" Spectrum tape copiers work?

There are some tape copiers, such as LERM that claim to be able to copy tapes which contain software that takes the full 48kbyte of RAM. However, this seems impossible on a Spectrum, when the whole ...
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  • 1,203
31 votes
1 answer
2k views

How does "bit-slip" copy protection work?

Some Apple II 5.25" floppies used a special pattern of bytes that could not be automatically detected by disk copying software. How could the pattern be invisible to disk copiers but detectable by ...
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