Help a newb question: ASPI layer?

I’m using the Sega CD emulator Gens and in order to boot to the CD, I have to install an ASPI layer otherwise the drives aren’t detected by Gens.

What is that exactly? Installing randomish things on my computer always makes me nervous :)

Thanks for any help.

It’s safe. It’s just an interface for getting raw access to SCSI devices and pseudo-SCSI ATAPI devices like CD drives, so it can get at data not normally available through the filesystem (if it’s even a standard filesystem on the disc).

Windows has its own interface for raw SCSI access, and some programs will support both, but ASPI has a lot more history behind it so some people prefer to keep using it.

(It’s probably easier to use, too, as the Windows interface is very primitive, but I haven’t actually seen the spec yet.)