Using stock (but patched to -19.9) RH9, I have huge cpu-hogging going on, or an I/O bound 1.2GHz Athlon on an ALi 1535D+/M1647 system. From looking at kernel archives, it looks like there was a problem with the chatty, smart ATA DVD-rom reader sending lots of debug data with every packet, to say how sure it was read correctly, how much UDF error correction was necessary, blahblahblah.

Is this even on target? Do I need to tell the generic ide driver to get on with it and 'Just DMA it?'

This is from mere reading DVD-R on combo-drives (one of which is a burner, and indeed the UDF system is mounted under /mnt/cdrom. Sorry, I don't have another kind.

Should I be simply running a utility like hdparm or such before running cp and mplayer and other apps?

This happens under WinXP (different boxen) too, BTW...so it's a common situation in some ways. Still...what's wrong and do I need to pick a 2.5 or 2.6test to fix it?