I'm sure this used to work, but:

# /usr/pkg/bin/cdrecord -v -dev=/dev/rcd0a speed=8 -data 43-beta.img
Cdrecord 1.9 (alpha-unknown-netbsd1.5.1.) Copyright (C) 1995-2000 Jörg
Schilling
TOC Type: 1 = CD-ROM
scsidev: '/dev/rcd0a'
devname: '/dev/rcd0a'
scsibus: -2 target: -2 lun: -2
/usr/pkg/bin/cdrecord: Invalid argument. Cannot open SCSI driver.
/usr/pkg/bin/cdrecord: For possible targets try 'cdrecord -scanbus'. Make sure you are root.

So... what am I supposed to be specifying?

dmesg says:
cd0 at atapibus0 drive 1: <8X4X32, , 5.AX> type 5 cdrom removable
cd0: 32-bit data port
cd0: drive supports PIO mode 4, DMA mode 2
cd0(pciide0:1:1): using PIO mode 4, DMA mode 2 (using DMA data transfers)

but I can't translate this into "scsibus:target:lun".

-s