So if I "dd if=/dev/cdrom", will the kernel stop accessing the device when the first read error appears?
Sometimes. And some other times, it will keep on reading, on each block producing huge timeouts and "hangs". And sometimes, it will read the last block fine (cat /dev/dvdrom), but of course to get EOF, you need one more read attempt - and instead of EOF, you get a kernel panic. Admittedly this was 1997 or 98 I tink, but it was a very definite reason why I made my ISO handling scripts.
I thought every block device has a readable block limit (determined by drive firmware).
Dunno, it might not work reliably for CDs. I don't think SCSI was made for CDs, so what happens if you demand info which isn't there? From the firmware of a couldn't-care-less commodity item? But turning off read-ahead makes it work, so I don't think that's the problem. Fact is Linux doesn't hack it, whatever the exact reason. Engage workaround(s). Volker -- Volker Kuhlmann is list0570 with the domain in header http://volker.dnsalias.net/ Please do not CC list postings to me.