Our application has lots of legacy file writing code, including a third-party dBase-like library that we have no control over. We still want to write data and a viewer onto CDs and DVDs. These should be readable under a W2K or XP PC without any particular software installations.

Until now, we used Roxio's DirectCD, which makes the drive letter transparently "writeable", so we didn't have to change our legacy code. This works quite well, but what we don't like about this approach is that the user has to deal with both the DirectCD GUI and our application. We would like to be able to control the functionality needed with our application through an API. DirectCD doesn't offer such an API, and it doesn't support DVD. We also considered the XP's native Image Mastering API, but it again only supports CD, and it buffers all files on disk, which we don't like.

Is there a possible solution with the Nero SDK? I have examined the documentation but wasn't able to answer that question. Can you help me, either with the Nero API, or a different tool/approach? If you need more information, I'll be glad to give them. Your hints are greatly appreciated.

No, I don't think, NeroAPI serves your needs.
It is no problem, to write data to CD/DVD even on the fly. But accessing the disc as you can do with InCD, is not supported.

Too bad. But thanks for letting me know!