I have a couple questions about the px_d8 tool. First, is the source available somewhere?

Second, does anyone know what SCSI commands it uses to do subcode reading?

I'm doing some tests on an old Nakamichi drive. It seems to support 0xD8 reads (even on data discs), but px_d8 fails if I ask it to additionally read subchannel data. So, it'll do scrambled reads, but whatever command px_d8 issues for reading subcodes isn't supported.