[TriLUG] why can't I dd an audio CD?

[Joseph Mack NA3T]

I just tried dd'ing some audio CDs. The audio CDs behave 
normally under Linux (can mount -t cdfs and see all the wav 
files, and can copy with cdda2wav), but dd=/dev/cdrom 
of=foo.out fails with a bad read on the first sector. dd on 
an iso9660 (data) cdrom works as expected.

Google isn't terribly helpful, apart from confirming that dd 
fails for everyone on audio CDs. I found postings which said

o audio CDs have a single spiral track (one posting) (but 
counter to this, cdda2wav sees the disks as sectors)

o dd doesn't read everything and in particular doesn't work 
for audio tracks

So dd fails, but I don't know why dd fails. I would have 
thought a CD just a pile of bits like a regular hard disk.

What am I missing?

Thanks Joe

-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!