[Cdrdao-devel] SCSI Read TOC format

[Ingo v. L. <in...@gm...>]

Hi there,

I apologize if my mail is not perfectly on-topic, but the chance to get 
competent support appears to be best on this list:
I'm developing firmware for a device that's capable of emulating, among 
other things, a CD-ROM drive. It was brought to my attention that the 
device was not recognized when connected to a MAC OS X host, so I 
compared its SCSI responses with those of several other drives. The 
primary source of confusion appears to be this SCSI Read TOC request 
(0x43) issued by OS X:

    43 02 00 00 00 00 00 FF FE 80

The Format field is set to 0000b (TOC), and the MSF flag is set to one 
(use MSF instead of LBA). According to the MMC spec the device is 
supposed to respond with a 4-byte header and one or more 8-byte track 
descriptors. All devices I checked for reference seem to use the 11-byte 
Full TOC track descriptor format (0010b), though, and apparently this is 
also what OS X expects. The other drives are flawlessly accepted by the 
host while it just displayed a "Cannot read CD" error message for my device.
So, am I just misinterpreting the spec or is this an error that was 
spread so widely that it became a sort of "common law"? And is OS X 
behaving sensibly when it's requesting format 0 and expecting to get 
format 2?

Cheers,
Ingo