> > That's against the our mantra: "do it right".
> 
> so some CD ROMs shouldn't be supported at all.
> 
> it's hardware problem in fact. not all devices has this.

bad/broken hardwares have been source of headache.  We have
quirk entries in device driver to save such devices.

> after poweron light is on as long as BIOS scans for CD-ROM's, then it's
> off, then it's back on after NetBSD resets IDE channel.
> 
> but there's some difference between how NetBSD and BIOS scans for devices!

Hmm, could you try booting the older release of NetBSD (boot
floppy is enough) to check if the symptom still arises?

--
SUNAGAWA Keiki <kei_sun@ba2.so-net.ne.jp>
May the peace be with us all.