according to acs-2 ยง7.19.6 p. 163, this is illegal, but i got a $20 dvd-rom that doesn't have a serial number. this doesn't sit well with 9load. here's a workaround for the broken hardware:
sdiahci.c:1711,1717 - /n/dump/2009/0224/sys/src/boot/pc/sdiahci.c:1711,1716 d->portno = i; d->driveno = -1; d->sectors = 0; - d->serial[0] = ' '; d->ctlr = c; if((c->hba->pi & (1<<i)) == 0) continue; acs-2 is the draft follow-on standard to ata-8. i put this and a similar fix the kernel on sources. /n/sources/contrib/quanstro/src/9loadaoe /n/sources/contrib/quanstro/src/9/pc/sdiahci.c (requires ../*/sd* and ../port/fis*, too) - erik