ASPI is a communications interface that allows software applications to communicate efficiently with SCSI and IDE devices by providing direct access to the hardware. Unfortunately, although ASPI is supposed to be a standard, there are a number of different versions of the individual ASPI layers, and some of them can cause problems in some computer configurations.
On most systems it's best to use the standard Microsoft ASPI layer, which is equivalent to the Adaptec version. You should only select one of the alternative ASPI layers if you experience problems with AudioCD MP3 Studio 2000 -- for example if your computer crashes when you access your CD-ROM drive or CD recorder or if you are unable to finalize audio CDs when recording.
Currently AudioCD MP3 Studio 2000 supports the Microsoft and CeQuadrat ASPI layers, but you will be able to download other versions from our website (http://www.ashampoo.com) as and when they become available.