🚀 go-pugleaf

In comp.sys.next.programmer, mike@media-lab.mit.edu (Michael Hawley) writes:
>Anyone have the driver code to read digital data
>from audio CD's using the CD-ROM drive?
>Digitizing through the DSP is adequate but silly.

I don't think it's possible with the NeXT CD-ROM drive (or with
most CD-ROM drives for that matter.)

The problem is that CDs have a strange blocking.  If I remember the
numbers correctly, CDs use 24 byte frames. 98 frames form one subcode
block - which contains 2352 bytes of music data and 98 bytes of subcode
data.  75 of these blocks makes up exactly 1 second of stereo 44.1K
music.  CD-ROMs store only 2048 data bytes in each of these 2352 music
blocks.  As I understand it, the standard chips that are used in CD-ROM
drives to read data don't give you access to the extra bytes in each
block, so at best, you would on be getting 87% of the music data.

I've read that the CD-ROM drive on some SGI systems can read all
the music data, so at least someone has made a CD-ROM drive that
can read the music data, but I think it requires more than just
the right software driver.  I could be wrong however.. the NeXT
CD-ROM might be able to do it.

On a related subject, I heard that some of the "newer" NeXT CD-ROM
drives could read multi-session Kodak Photo-CDs.  Does anyone know
if this is true?

Curt