I was just wondering, when I downloaded an old game that the publisher released meanwhile for free with an no CD crack, why such a file is required to play without a CD?

As I had to install the game with an ISO file by using a virtual disk drive, I was just curious, how it is prevented to not just fake a physical disk with a virtual diskdrive, instead of having to use a NO CD crack.

So how does this security concept work?

(I wasn't able to find a tag that might fit for this, so please feel free to add a more fitting tag for this. Thanks in advance)

1 Answer 1


Games that shipped on physical disks often checked to make sure the disk was in the CD-ROM Drive before allowing you to play. It was a simple and somewhat effective way to ensure the average consumer didn't pass the CD around to all their friends and still keep playing the game.

This was also done with Floppy Disks, and sometimes asking the user to enter the first word from a specific page in the accompanying player's manual.

The crack you mentioned was often done by someone looking to pirate the software. They'd modify the game's executable to jump over the code that made the CD check. If a studio later wanted to remove the check, but not redistribute the entire game with the art assets and everything, they could do the same.

  • 1
    My question was why the physical disk was required and why faking the physical disk with a virtual disk drive isnt working.
    – Zaibis
    Aug 24, 2018 at 14:53
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    For most of the early CD games, mounting a disk image would work. Some of the newer games would inspect the properties of the drive though, to see if it was a known virtualized disk system. If you want something more technical about what techniques were used for these checks, you'll need to wait for an answer from someone more familiar with that type of work.
    – nbering
    Aug 24, 2018 at 14:56
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    My experience with No CD cracks was that loading the ISO DID work, unless the software was too simple and only looked at the D:\ drive. Sometimes software would inspect device properties and see the virtual drive's driver or identifier and reject it. Aug 24, 2018 at 14:57
  • @Adonalsium raises a good point. The D:\ problem was annoying. I remember having to reconfigure my 2xCD-ROM machine so that my high-speed drive was at D:\ because games would only check that path.
    – nbering
    Aug 24, 2018 at 15:00
  • IMHO, virtual disk signature tend to be fixed , it is easy for the early day developer to detect it. But that part can be tweak by changing the virtual disk registry name slightly.
    – mootmoot
    Aug 24, 2018 at 16:45

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