I am trying to read from a Mitsumi CD ROM drive. The FAQ doesn't seem
too promising suggesting that there are an awful lot of variants. Still,
it seems a shame to admit defeat, and I may well have just forgotten
something simple.

In my kernel config (i386):

mcd0	at isa? port 0x170 irq 15	# Mitsumi CD-ROM drives
options MCDDEBUG


Output from dmesg:

NetBSD 1.2E (BASE) #18: Tue May 20 14:24:39 BST 1997
    prlw1@base.newn.cam.ac.uk:/usr/src/sys/arch/i386/compile/BASE
cpu0: family 5 model 2 step 5
cpu0: Intel Pentium (P54C) (586-class)
real mem  = 24768512
avail mem = 21663744
using 327 buffers containing 1339392 bytes of memory
mainbus0 (root)
pci0 at mainbus0 bus 0: configuration mode 1
pchb0 at pci0 dev 0 function 0
pchb0: Intel 82437FX (Triton) PCI, Cache, and DRAM Controller (rev. 0x02)
pcib0 at pci0 dev 7 function 0
pcib0: Intel 82471FB (Triton) PCI-ISA Bridge (rev. 0x02)
S3 Trio32/64 (VGA display) at pci0 dev 14 function 0 not configured
isa0 at pcib0
com0 at isa0 port 0x3f8-0x3ff irq 4: ns16550a, working fifo
com1 at isa0 port 0x2f8-0x2ff irq 3: ns16550a, working fifo
lpt0 at isa0 port 0x378-0x37b irq 7
wdc0 at isa0 port 0x1f0-0x1f7 irq 14
wd0 at wdc0 drive 0: <ST3660A>
wd0: 520MB, 1057 cyl, 16 head, 63 sec, 512 bytes/sec
wd0: using 16-sector 16-bit pio transfers, lba addressing
ed0 at isa0 port 0x300-0x31f irq 10
ed0: address 00:00:b4:32:e1:5e, type NE2000 (16-bit)
ed1 at isa0 port 0x340-0x35f irq 9
ed1: address 00:c0:df:49:5f:a1, type NE2000 (16-bit)
npx0 at isa0 port 0xf0-0xff: using exception 16
vt0 at isa0 port 0x60-0x6f irq 1: unknown s3, 80 col, color, 8 scr, mf2-kbd, [R3.32]
pms0 at vt0 irq 12
fdc0 at isa0 port 0x3f0-0x3f7 irq 6 drq 2
fd0 at fdc0 drive 0: 1.44MB 80 cyl, 2 head, 18 sec
apm0 at mainbus0: Power Management spec V1.1
apm0: A/C state: on
apm0: battery charge state: no battery
biomask 4040 netmask 4640 ttymask 56c2
boot device: wd0
root on wd0a swap on wd0b
root file system type: ffs

ie., no mention of mcd0 anywhere to be seen :( also, no mention of
anything else on irq 15. Has anyone got any clues for me?

Cheers,

 Patrick